P - Division of the Physical Sciences

Transcription

D e pa rt m e n t o f A s t ro n o m y
a n d A s t ro p h y s i c s
K av l i I n s t i t u t e f o r
C o s mo l o g i c a l P h ys i c s
Telescope Complementarity:
Optical is King
2015 Astro Immersion
March 27 – 29, 2015
Tucson, Arizona
Telescope Complementarity: Optical is King
Contents
I.Itinerary
II.
What is the Hubble Circle?
III.
Speaker & Participant Profiles
IV.
Reading Materials
A.
Articles for Professor Wendy L. Freedman and
Dean Edward “Rocky” Kolb:
Giant Magellan Telescope Project
B.
Articles for Professor Robert P. Kirshner:
The Accelerating Universe
C.
Articles for Professor Joshua Frieman:
The Dark Energy Survey and the Mystery of Cosmic Acceleration
D.
Articles for Assistant Professor Bradford Benson:
South Pole Telescope: Using Light from the Big Bang to
Backlight the Universe
E.
Articles for Professor Daniel P. Marrone:
The Event Horizon Telescope: A Detailed Look at Black Holes
F.
Articles for Jeffery J. Puschell:
Earth from Space: Weather Forecasting and Climate Monitoring
G.
Articles for Professor Angela V. Olinto:
Extreme Universe Space Observatory at the Japanese Module
V.Notes
I.
Itinerary
Astro Immersion 2015
Friday, March 27 | Arrival
6:00 pm
Cocktail Reception (Azul Restaurant, La Paloma Resort)
7:00 pm
Dinner
7:30 pm
Presented by Wendy L. Freedman and Edward “Rocky” Kolb
Saturday, March 28 | Mirror Lab and Discussions
8:30 am
Breakfast (La Paloma Resort)
9:30 am
Depart for UA Mirror Lab Tour
10:00 am
UA Mirror Lab Tour
12:00 pm
Lunch (Cottonwood Room, La Paloma Resort)
12:30 pm
The Accelerating Universe Presented by Robert P. Kirshner
The Dark Energy Survey and the Mystery of Cosmic Acceleration
1:30 pm
Presented by Joshua Frieman
2:30 pm
Break
2:45 pm
South Pole Telescope: Using Light from the Big Bang to Backlight the Universe
Presented by Bradford Benson
The Event Horizon Telescope: A Detailed Look at Black Holes 3:45 pm
Presented by Daniel P. Marrone
5:00 pm
End of session
7:30 pm
Depart for dinner
7:45 pm
Dinner (The Grill at Hacienda del Sol)
Sunday, March 29 | Brunch
9:30 am
Brunch (Cottonwood Room, La Paloma Resort)
10:00 am
Hubble Circle Update
Presented by Michael S. Turner and Angela V. Olinto
Earth from Space: Weather Forecasting and Climate Monitoring
11:00 am
Presented by Jeffery J. Puschell
Extreme Universe Space Observatory at the Japanese Module
12:00 pm
Presented by Angela V. Olinto
Immersion Concludes
1:00 pm
2015 Astro Immersion | April 27 – 29 7
II.
What is the Hubble Circle?
The Hubble Circle
The Hubble Circle is a group of philanthropic individuals who support the University’s goal to be a leader in
observational astronomy with gifts of $1 million or more.
Edwin Hubble (University of Chicago, AB in Physics 1910; PhD in Astronomy 1917) laid the foundation for
modern observational cosmology with his discovery that the universe extends beyond the Milky Way and that it
is expanding at a growing rate. It is in his spirit that the University of Chicago is advancing its stature as a leading
center of observational astronomy by joining the Magellan Consortium and becoming a founding partner for
the Giant Magellan Telescope (GMT).
Today’s cutting-edge research requires access to large, ground-based optical and infrared telescopes. The twin
6.5 meter Magellan Telescopes at Las Campanas Observatory in the Chilean Andes are widely acknowledged to
produce the best image quality currently available from a ground-based telescope. The GMT will be the world’s
largest telescope when it begins operations in 2021. By guaranteeing access to observatories that will stand at the
forefront of astronomical investigation in the 21st century, The University of Chicago will lead the next wave of
breakthrough discoveries that will change the way we think about the universe and our place in it.
To fully realize this vision, the University is recruiting members to the Hubble Circle. The support and involvement of these visionaries will prove integral to enabling Chicago’s world-renowned cosmologists to harness the
new generation of optical telescopes in their quest to find answers to fundamental questions about the early
universe as well as the nature of dark matter and dark energy.
Hubble Circle members will receive the following exclusive benefits:
- Sloan Digital Sky Survey Plate
- Invitation to annual Astro Immersion events
- Annual updates from the Astronomy & Astrophysics Chair and Kavli Director
- Invitations to travel to observational facilities in the United States, Chile and elsewhere
- Pre-publication notice of important discoveries
Hubble Circle Members
Donald E. Butterfield and Ken Ishiwata
AB ’53 (General Studies)
Alec Neill Litowitz
JD ’93 and MBA ’93 (Finance and Accounting)
Michael Thomas Long
AB ’75 (Physics)
John McGrain
Friend of the University
John A. “Mac” McQuown and Leslie W. McQuown
Friends of the University
Nicholas J. Pritzker and Susan S. Pritzker
JD ’75
Jeffery J. Puschell and Dana Puschell
AB ’75 (Physics)
Reuben Sandler
SM ’58 (Mathematics) and PhD ’61 (Mathematics)
Thomas and Sharon Zimmerman
Friends of the University
III.
Bradford Benson is an Associate Scientist at Fermi National Accelerator Laboratory and an Assistant
Professor of Astronomy & Astrophysics at the University of Chicago. Before becoming a professor, Dr. Benson
graduated from the University of Wisconsin-Madison in 1999, received his Ph.D. in physics from Stanford University in 2004, and was a postdoctoral researcher at the University of California-Berkeley and the University of
Chicago. Dr. Benson has published over 100 scientific papers. His scientific interests include clusters of galaxies,
radio and microwave wavelength detectors, and measurements of the cosmic microwave background, the 14
billion year old light from the Big Bang. Dr. Benson’s goal is to build instruments that can make observations
that answer some of the biggest questions in cosmology: What physics was responsible for the Big Bang? What
is the Universe made out of ? What is Dark Energy?
Gordon Freedman speaks and writes about change and technology in education and serves as an
advocate for advanced information systems, smart technologies, and big data analytics as agents in transforming
individual learning and institutional education. Mr. Freedman serves as president of the National Laboratory for
Education Transformation, a Silicon Valley non-profit devoted to the redesign of public education systems and
personal learning solutions, on par with corporate, consumer and governmental services. He is also the owner
and general manager of Knowledge Base, LLC, a higher education strategy consultancy established in 1998
to help education technology corporations, publishers, research institutes, museums and government agencies
manage their strategic transitions into technology and media-driven markets. From 2005 through the end of
2011, Mr. Freedman was Vice President of Global Education Strategy for Blackboard, Inc. and Executive Director of the Blackboard Institute. Prior his work in the education sector, he was a television and film executive
in Los Angles, where he was executive producer of the Sundance Film Festival award-winning documentary A
Brief History of Time about Cambridge University physics professor Stephen Hawking. Earlier, Mr. Freedman
was a network news producer and a national reporter based in Washington, D.C. He began his career as a Congressional staff member and investigator serving on committees in both the U.S. Senate and U.S. House of Representatives. Mr. Freedman is a graduate of Michigan State University and is a Fellow at SRI and was a Fellow at
University of California Berkeley’s Center for Studies in Higher Education.
Wendy L. Freedman joined The University of Chicago faculty as University Professor of Astronomy and Astrophysics in September 2014, following a distinguished, thirty-year career at the Observatories
of the Carnegie Institution for Science in Pasadena. Among her scientific achievements at Carnegie, Professor
Freedman was a principle investigator for a team of thirty astronomers who carried out the Hubble Key Project
to measure the current expansion rate of the Universe, an effort that began in the mid-1980s while she was a
post-doctoral scholar at Carnegie and completed in 2001. For eleven years (2003-2014) Professor Freedman
served as the Crawford H. Greenewalt Director of the Carnegie Observatories, and in 2003, was appointed
chair of the board of the Giant Magellan Telescope Project, a role she retains at Chicago. Her research interests
are directed at measuring both the current and past expansion rate of the universe, and in characterizing the
nature of dark energy, which is causing the expansion rate to accelerate. She is the Principal Investigator of a
program that uses the Spitzer Space Telescope to measure the Hubble constant to an accuracy of 3 percent.
Joshua Frieman is a senior staff member (Scientist III) in the Theoretical Astrophysics group at Fermilab and the Fermilab Center for Particle Astrophysics. He is also Professor of Astronomy and Astrophysics
at the University of Chicago, where he is a member of the Kavli Institute for Cosmological Physics. After a
postdoc in the SLAC Theory Group, he joined the scientific staff at Fermilab in 1988 and served as Head of
the Theoretical Astrophysics Group from 1994 to 1999. Dr. Frieman’s research centers on theoretical and observational cosmology, including studies of the nature of dark energy, the early Universe, gravitational lensing,
the large-scale structure of the Universe, and supernovae as cosmological distance indicators. The author of over
275 publications, he led the Sloan Digital Sky Survey (SDSS-II) Supernova Survey, served as chair of the SDSS
Collaboration Council, and as co-lead of the SDSS Large-scale Structure Working Group. He is a founder and
Director of the Dark Energy Survey, a collaboration of over 300 scientists from 25 institutions on 3 continents,
which built a 570-Megapixel camera to carry out a wide-field survey on the Blanco 4-meter telescope at Cerro
Tololo Inter-American Observatory in Chile to probe the origin of cosmic acceleration. He is an Honorary
Fellow of the Royal Astronomical Society, and a Fellow of the American Physical Society and of the American
Association for the Advancement of Science. He is Vice-President and former Trustee of the Aspen Center for
Physics. Dr. Frieman earned a B.Sc. degree from Stanford and a PhD in Physics from the University of Chicago.
18 2015 Astro Immersion | April 27 – 29
Laurence Hill is Senior Associate Provost at the University of Chicago. He is responsible for coordinating the planning and resourcing of a broad range of strategic programmatic and capital initiatives across campus.
He is also responsible in the Provost’s office for integrating the use of long-range financial models and other
analytic infrastructure critical to launching and sustaining academic initiatives. Previously, Mr. Hill was the Senior Associate Vice President for Program Development and National Laboratories, providing leadership for
science initiatives and joint research efforts with Argonne National Laboratory and Fermi National Accelerator
Laboratory. He also served as Assistant Dean for Research Operations in the Division of the Biological Sciences
(BSD) and the Pritzker School of Medicine, and before that, Assistant Dean for Planning in the BSD. Mr. Hill
received his MBA from the University of Chicago Booth School of Business, an M.A. in Religious Studies from
the University of Chicago Divinity School, and a B.A. from Indiana Wesleyan University.
Robert P. Kirshner is Clowes Professor of Science at Harvard University. Professor Kirshner is an
author of over 300 research papers dealing with supernovae and observational cosmology. His work with the
“High-Z Supernova Team” on the acceleration of the Universe lead to the 2011 Nobel Prize in Physics which
was awarded to his students. Professor Kirshner and the High-Z Team shared in the Gruber Prize for Cosmology in 2007 and the Fundamental Physics Breakthrough Prize in 2014. A member of the American Academy of
Arts and Sciences, he was elected to the National Academy of Sciences in 1998 and the American Philosophical
Society in 2004. Caltech named him the Distinguished Alumni Award in 2004 and he received an honorary
Doctor of Science from the University of Chicago in 2010. Professor Kirshner won the Dannie Heineman Prize
in Astrophysics in 2011, a Guggenheim Fellowship in 2012, and in 2015 was named Physics Laureate by the
Wolf Foundation. His popular-level book, The Extravagant Universe: Exploding Stars, Dark Energy, and the
Accelerating Cosmos, won the AAP Award for Best Professional/Scholarly Book in Physics and Astronomy.
Professor Kirshner graduated from Harvard College in 1970 and received a Ph.D. in Astronomy at Caltech.
Edward “Rocky” Kolb is Dean of the Division of the Physical Sciences and the Arthur Holly
Compton Distinguished Service Professor in the Department of Astronomy and Astrophysics at the University
of Chicago. Dr. Kolb’s research applies elementary-particle physics to the very early Universe, including cosmic
inflation models, gravitational production of particles, particle dark matter, ultra-high energy cosmic rays, and
high-energy neutrino astronomy. In 1983, he and Michael Turner created the Theoretical Astrophysics group
at Fermilab, now the Center for Particle Astrophysics. Together, they co-authored the influential monograph,
The Early Universe, and shared the AAS/AIP Heineman Prize for their role in establishing the field of particle
astrophysics and cosmology. In addition to over 200 scientific papers, he co-authored the popular history Blind
Watchers of the Sky, which received the 1996 Emme Award of the American Aeronautical Society. Dr. Kolb
currently serves on the boards of the Giant Magellan Telescope Organization and Adler Planetarium. He is a
Fellow of the American Academy of Arts and Sciences and the American Physical Society. Mr. Kolb earned his
BA from the University of New Orleans and his PhD in Physics from the University of Texas, Austin. He holds
an honorary degree, Doctor Honoris Causa, from the University of Lyon in France.
Michael Long is co-founder, CEO, and Chairman of Premier Wireless, Inc. Started in 1993, Premier
Wireless designs and manufacturers wireless video, audio, and data systems for use in the CCTV, Broadcast,
Military, and Law Enforcement markets. Prior to founding Premier Wireless, Mr. Long was the President of
Dynatech Spectrum, a subsidiary of Dynatech Corporation. While there, Mr. Long was responsible for the
conception and marketing of one of the earliest wireless video systems to be offered to the CCTV market. He
has published a number of articles and is co-inventor on two patents. In 2009, Mr. Long joined the University
of Chicago’s Physical Sciences Division Visiting Committee and became a member of the Board of Trustees of
the Mt. Wilson Institute and Observatory. In 2012, he joined the Board of Trustees of the Carnegie Institute
for Science. He served as Vice President of the Giant Magellan Telescope Corporation until 2014. He has a BS
in Physics from the University of Chicago with continued graduate studies at UCLA and Stanford University.
Daniel P. Marrone is an Assistant Professor of Astronomy at the University of Arizona. He was a
Hubble and Jansky fellow at the University of Chicago until joining the Arizona faculty in 2011. His research
addresses a variety of topics, including cosmology, the formation of galaxies in the early universe, and the physics
of black holes. In this work, Dr. Marrone makes use of cutting-edge astronomical facilities on the ground and
in space and often constructs new instruments to enable new types of observations. He is the author of more
than 100 refereed scientific publications and is a member of the American Astronomical Society. Dr. Marrone
received B.S. degrees in Physics and Astronomy from the University of Minnesota in 2001 and his PhD in Astronomy from Harvard University in 2006.
Lorel McMillan spent several decades writing about design and the arts for newspapers and magazines
in New York and in Chicago. Ms. McMillan has served as a trustee of Writers’ Theatre for fifteen years. In 2010,
she earned a MLA from the University of Chicago, informally concentrating on science in the early modern
period. She holds degrees from the Medill School of Journalism and Northwestern University.
Robert D. McMillan, M.D. is an orthopedic surgeon who has worked with Northshore University Health System throughout his career. With clinical teaching responsibilities first at Northwestern University and currently at the University of Chicago, Dr. McMillan also volunteers with medical education programs.
He received his medical training at Northwestern University and completed his residency at Cornell University’s Hospital for Special Surgery in New York City. His is an avid golfer and ardent fly-fisherman.
Rowan Miranda is Vice President for Operations and Chief Financial Officer at the University of
Chicago. Mr. Miranda joined the University of Chicago as the Senior Associate Vice President for Finance and
Administration and Treasurer, and became the Interim Chief Financial Officer in August 2014. He previously
worked as the Associate Vice President for Finance at University of Michigan and, prior to that, as an executive
partner at Accenture, leading its North American Finance and Performance Management Service Line offerings
for government and higher education. He has held a number of faculty appointments over the last 20 years at the
University of Illinois at Chicago, University of Pittsburgh, as adjunct professor at Carnegie Mellon University,
and visiting faculty at the University of Chicago Harris School of Public Policy. Most recently, he was an adjunct
professor at the University of Michigan’s Gerald R. Ford School of Public Policy. In addition to his B.S. in Accounting and M.A. in Political Science from the University of Illinois at Chicago, Mr. Miranda holds an M.A.
and a Ph.D. in public policy analysis from the University of Chicago Harris School of Public Policy.
Gary J. Morgenthaler is a partner at Morgenthaler Ventures, focusing on investments in the software and services industries. He was a past Director of Siri, Inc., which was acquired by Apple in April 2010
and BlueArc Corporation which was acquired by Hitachi Data Systems in September 2011. Gary is a current
Director of Nominum, NuoDB, OneChip Photonics and Overture Networks. Gary was also a co-founder and
past CEO of Illustra Information Technologies, Inc., where he served as a Chairman of Illustra’s Board until its
acquisition by Informix in 1996. He also served as Director of Catena Networks (acquired by Ciena (CIEN)),
Nuance Communications, and Premisys Communications and led the firm’s investments in Force10 Networks
and QuickLogic. From 1980 until 1989, Gary co-founded and served as CEO and Chairman of Ingres Corporation, a leading relational database software company. Previously he was with McKinsey & Co. as a management consultant, with Tymshare in software development and management, and with Stanford University in
software research and development. He received a BA from Harvard University.
Catherine “Cathy” Odelbo is the Executive Vice President of Global Corporate Strategy at
Morningstar, Inc. Ms. Odelbo joined Morningstar in 1988 as a mutual fund analyst and from 1995 to 2000
served as Senior Vice President of Content Development, as well as publisher and editor of stock and closedend fund research. In 2000, she was named President of Retail, overseeing all print and online products for individual investors. Ms. Odelbo was president of Morningstar’s global Equity and Credit Research division from
2009 until she assumed her current role in 2012. She holds a BA in American History and an MBA from the
University of Chicago Booth School of Business, where she graduated with honors. Ms. Odelbo is a member of
the Phi Beta Kappa Society and The Chicago Network.
Orjan Odelbo was born and raised in Sweden, but has been a Chicagoan for twenty years since he and
Cathy were married in 1995. He is a photographer by trade, and a full-time dad to their two teenaged children,
Signe (16) and Victor (14). His photography is now his art rather than a profession. Mr. Odelbo enjoys sports,
running, and Belgian beer.
Angela V. Olinto is the Homer J. Livingston Professor and Chair of the Department of Astronomy and
Astrophysics at the University of Chicago. She is the U.S. PI of the JEM-EUSO space mission and a member
of the international collaboration of the Pierre Auger Observatory, both designed to discover the origin of the
highest energy cosmic rays. She has made significant contributions to inflationary theory, the study of cosmic
magnetic fields, the nature of the dark matter, and the origin of the highest energy cosmic particles: cosmic rays,
gamma-rays, and neutrinos. She is a fellow of the American Physical Society and the Chair of their Division of
Astrophysics. She is a fellow of the American Association for the Advancement of Science, was a trustee of the
Aspen Center for Physics, and has served on many advisory committees for the National Academy of Sciences,
Department of Energy, National Science Foundation, and the National Aeronautics and Space Administration.
Professor Olinto received her B.S. in Physics from the Pontifícia Universidade Católica of Rio de Janeiro, Brazil,
and her Ph.D. in Physics from the Massachusetts Institute of Technology.
Jeffery J. Puschell is Principal Engineering Fellow at Raytheon Space and Airborne Systems in El Segundo, California. He is an internationally recognized expert in the system engineering of space-based imaging
and remote sensing systems. The author or co-author of more than 100 papers on a variety of topics in astrophysics, space-based imaging and remote sensing and optical communication, he holds several patents for innovative
passive and active remote sensors. He also chairs the Industrial Advisory Board for the Center for Metamaterials,
headquartered at City University of New York, and is a member of the US Department of Commerce Emerging
Technology and Research Advisory Committee. He is an Associate Editor of the Journal of Applied Remote
Sensing and Chair for the SPIE Remote Sensing System Engineering Conference. Dr. Puschell received his AB
in Physics from the University of Chicago and a PhD in Astrophysics from the University of Minnesota. In
addition to being a Raytheon Principal Fellow, he is a SPIE Fellow, and an Associate Fellow of the AIAA.
David Rousso is Founder and President of Pulse-ET. Founded in 2013, Pulse-ET designs and implements business analytics solutions for healthcare and public sector clients. Mr. Rousso is also an Executive Producer on Station: Science at the Frontier, a series dedicated to exploring the science taking place on the International Space Station. Prior to this, Mr. Rousso was Founded and President of EISCO Technology, an IT
consulting company that he sold to Logicalis in 2005. He stayed on as a Senior Account Executive at Logicalis
until the founding of Pulse-ET. Mr. Rousso also serves on the Board of Directors of the Art Center of Highland
Park and Kids Rank. He earned his B.A. from Northwestern University and his MBA from the University of
Michigan Ross School of Business.
Reuben Sandler has been Chairman and Chief Executive Officer of Intelligent Optical Systems, Inc.,
a research and development company that has been creating technologies in optical sensing and instrumentation since 1999. He retired as Chairman in 2006 and remains CEO today. Prior to that, he was Executive Vice
President for Makoff R&D Laboratories, Inc. before becoming President and Chief Information Officer for
MediVox, Inc., a medical software development company. Dr. Sandler currently serves on the Board of Directors
of Optech Ventures, LLC and the Board of Directors of IPCreate. Dr. Sandler is the author of four books on
the subject of mathematics and has held professorships at Victoria University of Wellington, the University of
Chicago, the University of Illinois, Chicago, the University of Hawaii, and Technion University of Haifa. Mr.
Sandler joined the Physical Sciences Visiting Committee in 2006. He earned his undergraduate and PhD in
Mathematics from the University of Chicago.
Michael S. Turner is the Rauner Distinguished Service Professor and Director of the Kavli Institute
for Cosmological Physics at The University of Chicago where he has been a faculty member since 1980. Trained
in general relativity and particle physics, Dr. Turner began to explore the connections between particle physics
and astrophysics and cosmology, and helped pioneer the interdisciplinary field of particle astrophysics and cosmology. In 1983, he and Edward W. “Rocky” Kolb created the Theoretical Astrophysics group at Fermilab, now
the Center for Particle Astrophysics. Together, they co-authored the influential monograph, The Early Universe,
and shared the AAS/AIP Heineman Prize for their role in establishing the field of particle astrophysics and
cosmology. Dr. Turner’s research has also been recognized with the APS’s Lilienfeld Prize, and the American
Astronomical Society’s Warner Prize; he is a Fellow of the American Physics Society, the American Association
for the Advancement of Science, and the American Academy for Arts and Sciences and a winner of the Klopsted
Prize of the American Association for Physics Teachers. He was elected to the National Academy of Sciences in
1997 and is the past Chair of its Physics Section. Dr. Turner received his BS in physics from Caltech, his M.S.
and PhD degrees from Stanford University, and an honorary D.Sc. from Michigan State University.
Joan Winstein has been active at the University of Chicago for many years. After a long corporate banking career, she formed Loan Strategies, Inc. to provide consulting to banks and creditors, specializing in restructuring, renegotiating, and resolving problem loan portfolios. She is Trustee for the Peter F. Drucker Literary
Works Trust, a docent for the Chicago Architecture Foundation, and has in the past served on the Governing Board of the Bulletin of the Atomic Scientists, as well as a number of educational organizations. Her late
husband, Bruce Winstein, was the Allison Distinguished Service Professor in the Physics Department at the
University of Chicago. Ms. Winstein holds a BA in Japanese from the University of Pennsylvania, an AM in Far
Eastern Civilizations from the University of Chicago, and an MBA from Golden Gate University.
IV.
Reading Materials
A. Articles for Professor Wendy L. Freedman
and Dean Edward “Rocky” Kolb:
IV.
Reading Materials
B. Articles for Professor Robert P. Kirshner:
The Accelerating Universe
IV.
Reading Materials
C. Articles for Professor Joshua Frieman:
The Dark Energy Survey
and the Mystery of Cosmic Acceleration
IV.
Reading Materials
D. Articles for Assistant Professor Bradford Benson:
South Pole Telescope:
Using Light from the Big Bang to Backlight the Universe
DANIEL LUONG-VAN/NATIONAL SCIENCE FOUNDATION
Pole position
The most inhospitable places on Earth are
the best spots to witness the birth of the
universe, finds Govert Schilling
36 | NewScientist | 25 May 2013
Braving the extremes is
all in a day’s work at the
South Pole Telescope
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25 May 2013 | NewScientist | 37
ASAD ABOOBAKER
GOVERT SCHILLING
AMIBA/ASIAA
AMiBA in Hawaii (left),
EBEX detector (bottom
left) and the Atacama
Cosmology Telescope
(right)
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38 | NewScientist | 25 May 2013
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The Polarbear
experiment in Chile is
almost 5200 metres up
POLARBEAR TELESCOPE
“While a wind chill of -40 °C
is considered balmy by
residents of the South Pole
station, my tears freeze”
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moldobpp)Ïp^vpPmbodbi+N
Govert Schilling is an astronomy writer based in
Amersfoort, the Netherlands. He spent a week in
Antarctica and the South Pole in December 2012 as
a selected media visitor of the US National Science
Foundation’s Antarctic Program
25 May 2013 | NewScientist | 39
IV.
Reading Materials
E. Articles for Professor Daniel P. Marrone:
The Event Horizon Telescope:
A Detailed Look at Black Holes
Imaging a Black Hole
Einstein’s
Shad w
WILLIAM GARNIER / ALMA (ESO / NAOJ / NRAO)
Illustration by Leah Tiscione
A planet-wide telescope sets its sights on
the well-kept secrets of black holes.
20 February 2012 sky & telescope
These days, black holes are
about as common as dust bunnies.
Millions of them dot the Milky Way’s disk in stellar
binary systems, gorging on material from their companion stars. Supermassive beasts lurk in the cores of most
large galaxies and may even influence their hosts’ formation and evolution.
But even though black holes appear to be just about
everywhere, we’ve never actually seen one. That might
seem a moot point, considering they swallow light. Nevertheless, as excellent as the circumstantial evidence is
for their existence, black holes may not look how we think
they do. Nor does current evidence prove the veracity of
general relativity (GR), Einstein’s theory of gravity that
predicts — much to its creator’s horror — the formation
of these compact massive objects. We don’t even know for
certain that relativity’s description of spacetime, and black
holes, is correct: GR has never been tested in strong gravitational fields like those created by gargantuan black holes.
All that may be about to change. Astronomers across
the world are joining forces to create the Event Horizon
Telescope (EHT), a network of radio observatories that
will stretch from the South Pole to Hawaii and southern
Europe. These antennas will work together like a single
planet-sized dish, peering into galactic hearts to study
what happens near the event horizon, the closest distance
light can approach before a black hole’s gravity drags it
so deep inside that we can no longer see it falling in. The
EHT should unmask black holes, revealing how they feed
and grow. More important, it will put everything we know
— or think we know — about gravity to the test.
CAPTURING THE BEAST Famously camera-shy, black
holes may finally reveal themselves to astronomers’ careful
gaze in the next decade. This simulated image shows what
our Milky Way’s central black hole might look like to the Event
Horizon Telescope, with the silhouette created by the extreme
bending of light from accreting matter around the object.
The Silhouette
So far GR has passed every test, from explaining delays in
satellite signals to predicting the orbits of neutron stars
(S&T: August 2010, page 28). But Newtonian mechanics also passed many tests in the two centuries between
its publication and Einstein’s theory of gravity. And
physicists are well aware that GR fails to describe the
microscopic realm, where they have to turn to quantum
mechanics. The question is, how far can GR be pushed?
To answer this question, astronomers must probe
where Newtonian mechanics breaks down: the innermost
stable circular orbit, or ISCO (S&T: May 2011, page 20).
The ISCO is the closest path material can follow around
a black hole without falling in. But even though material
inside the ISCO may still lie outside the event horizon,
AVERY BRODERICK (UNIV. OF WATERLOO & PERIMETER INST.) / ABRAHAM LOEB (HARVARD-SMITHSONIAN CFA)
Camille M. Carlisle
that material will eventually plunge into the black hole,
no matter how fast it’s going.
“Newton would look at that orbit and say ‘That’s
crazy,’” says EHT project leader Sheperd Doeleman (MIT
Haystack Observatory). There’s no ISCO in Newtonian
gravity: as long as material stays outside the object it’s
circling, it will continue to orbit, without spiraling in. But
in GR, a black hole’s gravitational potential is proportional
to 1/r3 (r is the distance between the black hole and an
orbiting particle) instead of the 1/r of Newtonian theory
— which means the well sinks a whole lot more near the
black hole in GR than Newtonian theory predicts. This
effect overwhelms even the centrifugal energy of orbital
motion. Circular paths become unstable, and like a penny
in a coin vortex, material plunges past the event horizon.
W H AT I S A B L AC K H O L E?
A black hole is an object that is so massive and compact
that it creates an inescapable, four-dimensional pit in
spacetime. But a black hole is not made of matter: it
doesn’t have a hard surface. From the inside, a black
hole is a cosmic whirlpool, an object made of warped
spacetime, whose outer “edge” is the event horizon.
From the outside, though, a black hole can be completely
described with just three numbers: its spin, mass, and
electric charge. Generally there’s no overall charge, so
charge can be ignored, reducing the variables to two.
Sk yandTelescope.com February 2012 21
VIEWING ANGLES Depending on how the accretion disk around our galaxy’s central black hole
is tilted to our line of sight, light from an orbiting
hot spot could be lensed in a variety of ways. This
sequence moves from looking down at the disk from
above to seeing it from its side, with the spot behind
the hole. The strength of the black hole’s gravity
determines how light bends near the event horizon.
Supernova Remnants
Sgr B2
Supernova Remnant
Sgr B1
Sgr A
Supernova Remnants
tic
lac
Ga
r
ato
equ
NAMIR KASSIM (NAVAL RESEARCH LABORATORY) ET AL.
Sgr C
A SINGULAR NEIGHBORHOOD Although gas and dust obscure the Milky
Way’s center in visible light, its innermost parts show clearly in this radio image
made using data from the NRAO’s Very Large Array. The diagonal orientation
results from the Milky Way’s disk (Earth’s orbit around the Sun is inclined to the
galactic plane). Inside the Sgr A region hides the black hole known as Sgr A*.
GR simulations make specific predictions about how
the near-ISCO environment should appear to EHT scopes.
If a disk of gas and dust surrounds a black hole, the event
horizon should look like a dark silhouette, surrounded by
the glow of accreting material and framed with streaks
of light. The silhouette effect happens for two reasons.
First, light is fighting to survive. The black hole sits in the
midst of glowing accreting material heated by friction and
gravitational acceleration. But toward the disk’s center,
light has to struggle to escape the indentation the black
hole makes in the fabric of spacetime. As a photon loses
energy, its wavelength becomes longer, until it’s stretched
to infinity and right out of existence.
The second and prevailing reason for the silhouette
effect is what happens to radiation emitted by material
on the event horizon’s far side. The black hole blocks this
light from our direct view, but it gravitationally lenses
this radiation to curve around the central object to where
we can see it, creating a darker center. The lensed light
should form long streaks around the silhouette, looking rather like the diamond ring of a total solar eclipse
— except in this image the light is emitted at radio
wavelengths, not optical. While this radiation is gravitationally redshifted by the time it reaches us, the effect is
insubstantial: a photon originating from the ISCO with a
wavelength of 1.06 mm arrives at Earth at 1.3 mm.
These processes create what looks like a shadow but
isn’t. And how streaks stretch around the silhouette
depends on how the black hole’s gravity lenses light
near the ISCO — which depends on what kind of gravity astronomers are dealing with. If observations reveal
unforeseen phenomena (such as bizarre silhouette
shapes), it could indicate that Einstein’s theory breaks
down in strong gravity.
Images also depend on how matter accretes onto black
holes. Material falling in radially (that is, without orbiting) onto a nonspinning black hole would create a symmetrical image with a central “shadow.” But if the accreting material is orbiting the black hole, the image will
appear asymmetrical because material moving toward us
looks brighter due to relativistic effects.
That’s all in theory. While theorists have constructed
excellent models over the past three decades of what goes
on around black holes, they need observations to confirm
A. BRODERICK (UNIV. OF WATERLOO & PERIMETER
INST.) / A. LOEB (HARVARD-SMITHSONIAN CFA)
them. As Abraham Loeb (Harvard-Smithsonian Center
for Astrophysics) explains, “It would be very instructive to
see, for the first time, how nature does it in reality.”
The EHT’s first target is Sagittarius A* (abbreviated Sgr
A* and pronounced “A-star”), the supermassive black
hole candidate at the center of our Milky Way. Measurements by UCLA and Max Planck Institute astronomers
have pegged our galaxy’s beast at roughly 4 million solar
masses by measuring the orbital motions of stars in the
galactic center. At 26,000 light-years’ distance, Sgr A*’s
event horizon will appear 53 microarcseconds wide.
That’s about the size of a poppy seed in Los Angeles
seen from New York City. Even so, Sgr A* has the largest
apparent event horizon of any black hole candidate.
Astronomers plan to zoom in on this minuscule target
with a technique called Very Long Baseline Interferometry.
VLBI combines observations from radio telescopes far away
from one another into a single enhanced image, just as
though astronomers had used one big dish that spanned
the distance between the scopes. Because a telescope’s
theoretical resolution improves as its diameter increases,
VLBI dramatically improves observing capabilities. The
diameter of a “virtual” radio telescope stretching from
Hawaii to Chile, for example, has the same resolution as
that of a single dish 9,450 kilometers (about 5,870 miles)
wide. Astronomers at different locations must observe
simultaneously, but they can combine their observations to
create a single, cohesive picture.
In 2007 EHT astronomers led by Doeleman observed
Sgr A* using a three-station VLBI array that combined
the Arizona Radio Observatory’s 10-meter Submillimeter
Telescope (ARO/SMT), a 10-meter element of the Combined Array for Research in Millimeter-wave Astronomy
(CARMA) in California, and the 15-meter James Clerk
Maxwell Telescope (JCMT) atop Mauna Kea. Observing
in the 1.3-mm (230-GHz) band, the astronomers detected
structure in the ionized gas right around Sgr A* at a distance of roughly four times the size of the event horizon
(S&T: March 2010, page 14).
But astronomers don’t yet know what that structure is.
“You can’t reconstruct the image from only three telescopes,” says Doeleman. “So I know there’s something com-
S&T: GREGG DINDERMAN
Acquiring Target
ALL OVER THE MAP Capturing a black hole takes a planet-sized
telescope — or a planet covered in telescopes working together.
Shown are the various international sites participating, or expected
to participate, in Event Horizon Telescope observations.
Planned
Already used
pact there, I know there’s something about the size of the
event horizon, but I can’t tell you exactly what it looks like.
To do that, we have to extend the VLBI to more telescopes.”
The observations constrained Sgr A*’s angular size to
37 microarcseconds, which translates to a physical diameter of about four-tenths of an astronomical unit (a.u.).
You’ll notice that that number is smaller than the event
horizon’s size: Doeleman and his colleagues think the Sgr
A* source may be a bright spot in an accretion disk or a
jet that is slightly offset from the unseen black hole.
In April 2009 the astronomers added a second CARMA
scope and spotted a flare in Sgr A* that appeared between
the second and third observing days. This variability
matches similar activity seen in other multiwavelength
campaigns, bolstering the claim of event-horizon-scale
structure. VLBI measurements also show that the Milky
Way’s central black hole probably doesn’t spin very fast
and that its accretion disk is more edge-on than face-on
from our vantage point.
Violence Unmasked: M87
EHT astronomers also want to tackle the center of M87.
This giant elliptical galaxy lies roughly 52 million lightSk yandTelescope.com February 2012 23
THE HEART OF
THE MATTER
STREAM Deep
inside the elliptical
galaxy M87, a supermassive black hole
creates a high-speed
jet that shoots from
the galaxy’s center.
Recent observations
suggest the jet indeed
begins at a fixed point;
everything shown here
hides in the jet’s bright
core (shown below).
Accretion disk
Jet’s base
S&T: LEAH TISCIONE
Black
hole
years away, 2,000 times farther than Sgr A*. Astronomers
think that a 6.4-billion-solar-mass black hole (more than
1,000 times more massive than Sgr A*) lurks in M87’s
core. A black hole of that extreme mass would have an
event horizon roughly 135 a.u. wide, just larger than the
Kuiper Belt. But at M87’s distance, the event horizon’s
angular size would be less than 8 microarcseconds —
amazingly small, and yet this tiny horizon is the second
largest candidate after the Milky Way’s black hole. Lensing effects may make the accretion disk’s inner edge
appear larger, too, between 34 and 54 microarcseconds.
M87 is also fascinating because its core emits incredible
amounts of radiation. Such active galaxies can produce
1 trillion times the Sun’s energy, all in a region smaller
than our solar system. Many active galactic nuclei shoot
jets of plasma into intergalactic space (S&T: April 2010, page
20); M87’s single visible jet stretches 5,000 light-years long.
Last September Japanese scientists not involved with
the EHT reported VLBI measurements suggesting that
M87’s jet begins at a fixed point 14 to 23 times the event
horizon’s diameter from the black hole. That distance
is surprisingly small: previous studies of jets that point
straight at Earth had suggested separations thousands
of times larger. But M87’s jet is somewhat sideways from
Earth’s point of view, so the Japanese astronomers could
see how the stream’s bright, unresolved base changes
location with wavelength, appearing to narrow in on the
black hole’s location. The team observed at six wavelengths from 2 to 43 GHz using an array of 10 antennas
stretching from Hawaii to the Virgin Islands. With that
span they could resolve details 400 times finer than
Hubble can in optical light. Resolution at EHT wavelengths should be several times better and should allow
radio astronomers to directly image both the jet’s origin
and accretion flow around the black hole.
M87 is a particularly attractive target because its light
output varies on a much longer timescale than Sgr A*.
Why these sources vary isn’t definitively known. Fluctuations may be caused by “hot spots” in the accretion disk,
which appear to flare as they approach us.
These structural changes during observing runs will
smear images, reducing resolution and making it more
difficult to image a black hole’s silhouette. But high-frequency VLBI should be able to resolve changing structure
from orbiting hot spots by capturing snapshots over short
time intervals. Source signals can then be summed to
reflect how the structure changes with time. Watching
these changes will allow EHT astronomers to time hot-
JET SETTER Three shots of M87’s long jet, each in a different wavelength range (purple is X-ray, blue is radio, pink
is optical), all show the same bright core (lower left in each
image) coincident with the galaxy’s nucleus.
X-RAY: NASA / CXC / MIT / H. MARSHALL ET AL.; RADIO: F. ZHOU, F. OWEN (NRAO), J. BIRETTA (STSCI); OPTICAL: NASA / STSCI / UMBC / E. PERLMAN ET AL.
WILLIAM GARNIER / ALMA (ESO / NAOJ / NRAO)
MANY EYES MAKE LIGHT WORK The Atacama Large Millimeter/submillimeter Array (ALMA) is taking shape in the northern
Chilean desert. Only a fraction of the planned 66 antennas appear in this photo.
spot orbits, and because hot spots are close to the black
hole, their orbits move through relativistic anomalies not
described by Newtonian gravity. By clocking these orbits,
observers can test predictions of spacetime’s structure
near the ISCO.
“I honestly think that the real gold mine will be the
non-imaging observations in which we monitor the time
variability of Sgr A*,” says Doeleman. By timing “blob”
orbits near the ISCO, the team can also estimate the black
hole’s spin by comparing the measured orbital period
with the predicted one to see if the monster’s spin is
speeding up disk rotation. It is these orbits, even more
than the silhouette, that will determine how closely Einstein’s predictions match reality.
What’s Next
The EHT project has made great strides in the last few
years, but there’s still a long road ahead. With more than a
dozen contributing institutes in Asia, North America, and
Europe, the astronomers have many details to iron out.
One detail is the installation of masers — devices that
use stimulated microwave emission from atoms to keep
time. Because the EHT will combine observations conducted simultaneously around the world, accurate clocks
are essential: the masers lose only a second over 100 million years. But some facilities’ masers need maintenance,
and others don’t even have one yet.
Telescope modifications and various measurements also
have to be made. To properly reconstruct the observations
back at Haystack Observatory — Doeleman’s home base
and EHT headquarters — astronomers need to know each
observing site’s location to within a couple of feet. Such
exactitude can take hours to calibrate, and earthquakes and
spreading tectonic plates change site locations over time.
Achieving finer resolution will be the key to success.
EHT astronomers plan to improve resolution in part
by moving to shorter wavelengths. They’re particularly
focused on the 0.8-mm (345-GHz) band which, along with
1.3 mm (which Doeleman’s team used in 2007 and 2009),
is one of two main atmospheric windows in the millimeter/submillimeter range.
The challenge with 345 GHz is weather. Atmospheric
TH E E V E N T H O R I Z O N
You don’t have to be Einstein to calculate the radius of a black hole’s
event horizon. In 1783 British natural philosopher John Michell
predicted the existence of “dark stars” using Newtonian mechanics.
He described an object that was compact enough that light particles
leaving its surface would be slowed and then pulled back down
by the star’s gravity. Although photons don’t actually slow down
as Michell and others hypothesized, the formula for calculating a
star’s critical radius remains the same. For a nonspinning black
hole, the event horizon’s radius is R=2GM/c2 where G is Newton’s
gravitational constant and c is the speed of light.
Sk yandTelescope.com February 2012 25
SHEPERD DOELEMAN
TEAMWORK Members of the Event Horizon Telescope project (plus one eavesdropper: the author is in the back row) gathered at the
MIT Haystack Observatory in January 2010 to hash out their strategy. Sheperd Doeleman stands third from left in the back row.
water vapor can interfere with observations at this wavelength, making “high and dry” site conditions crucial.
Astronomers have had some success with monitoring
water-vapor fluctuations during observations and subtracting the effects from data later. EHT scientists also
plan to use the Atacama Large Millimeter/submillimeter
Array (ALMA), a network of 66 radio telescopes being
assembled in northern Chile. Although ALMA has only
about a third of its dishes in place it has already released
its first images and begun an observing program. Astronomers will soon use the array to look at how Sgr A*’s
behavior changes at different wavelengths, and the EHT
team has already received international funding to phase
ALMA with the global network.
ALMA is a “change in the firmament of VLBI,” says
Doeleman. Quite possibly the largest astronomy project
in history, when completed it will have a resolution of less
than 20 milliarcseconds at 345 GHz. If the EHT team can
combine ALMA with seven to ten other antennas, astronomers should achieve an angular resolution of 20 microarcseconds or better, clearly revealing Sgr A*’s silhouette.
EHT astronomers are hoping for a final list of stations
committed to the project by 2015. During that time more
facilities will come online, including the Large Millimeter
Telescope (LMT), a joint American-Mexican project east
of Mexico City that achieved first light last summer and
has already signed onto the endeavor.
Meanwhile, observations are coming closer to revealing the secrets of black holes. Many astronomers are
confident in the EHT, and the project received a thumb’s
up from the Astro2010 Decadal Survey. “We have the
necessary technology and it was demonstrated to work on
a smaller-scale project,” says Loeb. “I think it’s likely that
the project will be successful.”
Doeleman agrees. Advances in VLBI and our understanding of galactic centers make it almost certain that
astronomers will directly image black hole silhouettes
within the next decade, he says. And as new instruments
come online, radio astronomers will want to observe at
these wavelengths for a variety of projects, making observation time harder to come by in the future. Now is the time
for the EHT, says Doeleman. “We should be bold.” ✦
Camille M. Carlisle is a former S&T intern who recently
returned to the staff as assistant editor. This article is based
on work from her MIT master’s thesis, “Heart of Darkness.”
NEWS&ANALYSIS
Plateau de Bure
SMT
IRAM
LMT
ASTE
ALMA
APEX
ASTRONOMY
build up a high-resolution image of distant objects.
In a sense, EHT has begun observing already. For several years, Doeleman, Marrone, and colleagues have
been observing Sgr A* using dishes in
Hawaii, Arizona, and California. They
have seen features of the galactic center
on the same scale as the black hole, although
they don’t yet have the resolution to image its
surface, the event horizon. To improve resoSouth Pole
Telescope
lution they need to use shorter wavelengths,
a longer baseline, or both. The shorter wavelengths are on the way: The team hopes soon
to switch its observations from light with a
wavelength of 1.3 millimeters to 0.83 millimeters—fortuitously, a wavelength in which
the material of the galactic plane is relatively
transparent. But they are “pushing up to near
don’t see problems getting the resources,” the limit of the radio window in the atmosphere,” Marrone says.
Doeleman says.
To extend the baseline will require more
Black holes are extremely difficult to see
directly because they emit no light, except telescopes. About a dozen around the world
possibly the proposed very faint Hawking either are equipped to work at such short
radiation. Astronomers have inferred the wavelengths or can be adapted relatively
presence of black holes by observing nearby cheaply. In addition, EHT needs to incorpogas or orbiting stars. Being able to observe rate the Atacama Large Millimeter/Submilone directly would be a huge advance for limeter Array (ALMA) in Chile (Science, 30
astrophysicists. “Black holes may be part September 2011, p. 1820). ALMA’s 66 dishes
of our everyday lives, but they haven’t been high in the Andes will match the collecting
proven. No one has seen an event horizon,” power of a 90-meter-wide dish. “ALMA is
Falcke says. As well as obtaining proof, key because of its enormous collecting power
direct observation would allow astronomers and sensitivity,” says theorist Dimitrios Psaltis
to study how black holes swallow up nearby of the Steward Observatory. It is also far from
material, a process known as accretion, other observatories, creating a long baseline.
EHT researchers at Hayand how the jets of matestack have won $4 million
rial often seen coming out
from the U.S. National Sciof them form. They could
ence Foundation to equip
also conduct precise tests
ALMA for VLBI. ALMA,
of general relativity, somewhich is not yet complete,
thing never done in such a
should be ready to play a
strong gravitational field.
part in EHT by 2015. To get
Our galaxy’s central
an even longer baseline, the
black hole, known as Sagitproject would also like to
tarius A* (Sgr A*), is thought
to be 4 million times as masenlist the South Pole Telesive as the sun but only 30
scope (Science, 16 March
times as wide, smaller than Eye of the storm. Simulation of hot 2007, p. 1523), but it will
Mercury’s orbit. Proponents gas around a black hole.
require upgrading to make
of EHT believe they can
it suitable.
image it—or rather, see its “shadow” against
EHT’s enthusiastic reception at Tucson has
a bright background of hot gas—using a tech- set the ball rolling, and researchers have set
nique known as very long baseline interferom- up a committee to work out the details of an
etry (VLBI). It takes data from widely spaced international collaboration. “We’re aiming for
dishes and combines them as if they were two an MOU [memorandum of understanding]
small patches of a large dish. A VLBI array this summer, though tests and work will go on
lacks the light-collecting power of a full dish under the current, less formal, arrangements,”
–DANIEL CLERY
its size, but with enough small patches it can Marrone says.
Downloaded from www.sciencemag.org on January 26, 2012
CARMA
CSO
JCMT
SMA
Global coverage. Radio telescopes that could play
a role in the Event Horizon Telescope.
CREDIT: SCOTT NOBLE/RIT
Worldwide Telescope Aims to Look
Into Milky Way Galaxy’s Black Heart
The center of our galaxy—surrounded by a
maelstrom of stars, gas, and dust, and separated from us by 26,000 light-years of space
filled with all the detritus of the galactic
plane—is one of the most challenging things
for astronomers to observe. Last week, astronomers gathered in Tucson, Arizona, to work
out a plan to combine data from radio telescopes worldwide and create, in effect, a dish
the size of Earth. With such a virtual instrument, they say, they’ll be able to peer into our
galaxy’s heart and see the supermassive black
hole that resides there.
“It would be an amazing thing. It’s never
been done before, getting an image of a black
hole,” says one of the project’s organizers,
astronomer Daniel Marrone of the University of Arizona’s Steward Observatory. Heino
Falcke of Radboud University in Nijmegen,
the Netherlands, agrees. “This is a very, very
important thing to do,” he says. Despite such
enthusiasm, however, it’s not yet clear how a
worldwide collaboration would be organized
or funded. “Most of the relevant telescopes
had someone present [in Tucson], and all
wanted to make it work. But there was no real
consensus on how to do it,” says Falcke, who,
along with two colleagues, first suggested in
2000 that such observations might be possible
(Science, 7 January 2000, p. 65).
The organizational details are “still in
flux,” says Shep Doeleman, an astronomer
at the Massachusetts Institute of Technology’s Haystack Observatory in Westford and
principal investigator of the project, known
as the Event Horizon Telescope (EHT). But
with such a tantalizing scientific goal and
an estimated cost of a few million dollars to
upgrade instruments at some telescopes, “I
www.sciencemag.org
SCIENCE
VOL 335
27 JANUARY 2012
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Hunting Black Holes at the South Pole
By Seth Fletcher | February 26, 2015
Each of the telescopes that the astronomers of the Event Horizon
ADVERTISEMENT
Telescope (EHT) are currently working to bring into their blackhole-observing, planet-size array is a special case. Mexico’s Large Millimeter Telescope,
for example, is an enormous single dish on top of an exceptionally high mountain, not to
mention the biggest science project of any kind in its country. The Atacama Large
Millimeter Array (ALMA) is a billion-dollar class instrument, the world’s most powerful
radio telescope.
The South Pole Telescope is a special case in several ways. First, the obvious: it’s at the
South Pole. That makes it incredibly hard to get to even in good weather, and completely
inaccessible during the austral winter. But there are less obvious distinguishing
characteristics as well. For one, the South Pole Telescope was designed for the very specific task of studying the cosmic microwave
background—something completely different than what the astronomers of the EHT want it to do.
The South Pole Telescope. Credit: Daniel Luong-Van,
National Science Foundation
Which is why last December, University of Arizona-Tucson astronomer and EHT collaborator Dan Marrone flew, along with several
colleagues, to the South Pole. Their job was to install the gear the South Pole Telescope would need to join the EHT in observing black
holes.
Normally, the South Pole Telescope’s 10-meter dish funnels extremely faint radiation from the cosmic microwave background into a
camera called a bolometer. “That camera effectively just measures the heat from the sky in a given direction by sensing how much the
accumulated light heats each detector,” Marrone explains. To do Very Long Baseline Interferometry (VLBI), the technique used by the
Event Horizon Telescope, the SPT needs a different kind of camera—a single-pixel instrument that records the waveform of microwaves
(specifically those with a frequency of 230 GHz) hitting the telescope. With that single, highly sensitive pixel, Marrone explains, “we can
actually record a ‘movie’ of the electric field that the radiation from our targets is creating on the surface of the telescope.”
Eventually, during a full Event Horizon Telescope observing run, telescopes around the world will record such a “movie” on banks of
8-terabyte hard drives, then ship them back to MIT’s Haystack Observatory near Boston, where scientists will combine the data
collected at all sites using a supercomputer called a correlator.
By the time Marrone left Tucson on December 1, his team had already shipped 13 crates of equipment to the Pole. When Marrone
arrived on December 9, only two of those crates were waiting for him. “It turns out never to be easy to do anything at the South Pole,”
Marrone says.
For the first couple of weeks, as cargo trickled in, Marrone and his colleagues did what work they could. Space was tight, and the
building was under construction. “For the first month and a half we were there, every day there was someone soldering with an
acetylene torch in our ear, filling the air with weird acrid smoke,” Marrone says. When last of the straggling cargo arrived in late
December, “we could really fly, and so we did,” Marrone says. “They were very long days. We’d stagger out at 8 or 8:30 am, come back
for lunch or dinner and work until midnight. Christmas, New Year’s, it didn’t matter.”
In mid January, Marrone and crew finished their installation and pointed the modified telescope at the sky. They obtained first light
with the South Pole Telescope VLBI receiver early on January 16, local time, making images by scanning their single pixel across the sky
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and, in Marrone’s words, “making maps of the pixel value recorded for each sky position.”
The official first light image, signed by the South Pole installation crew, is a map of carbon monoxide near the center of the Milky Way.
A molecular cloud near the galactic center as seen
by the modified South Pole Telescope. Credit: Dan
Marrone
Another image depicts the moon at 230 gigahertz. “Instead of seeing reflected light, you see the heat escaping from the moon’s surface,”
Marrone says. “Notably the crescent is wider at 1mm than in the optical, because the parts of the moon that have just lost the sunlight
are still cooling. You can also see real signatures of the dark and light patches that you’re used to seeing with your eye.”
The moon at 230 GHz, captured by the South Pole
Telescope. Credit: Dan Marrone
These are just test images, but they prove that the equipment that will allow the South Pole Telescope to join the Event Horizon
Telescope works. The next step will be to link the South Pole Telescope up with another, faraway telescope. The SPT and the Atacama
Pathfinder Experiment (APEX) telescope in Chile observed together not long after the SPT recorded the images above, and the resulting
data is currently being analyzed at Haystack Observatory. If “fringes” emerge, it will be a big step toward getting the full EHT array
ready to take a picture of the black hole at the center of the Milky Way.
About the Author: Seth Fletcher is a senior editor. Follow on Twitter @seth_fletcher.
More »
The views expressed are those of the author and are not necessarily those of Scientific American.
Scientific American is a trademark of Scientific American, Inc., used with permission
© 2013 Scientific American, a Division of Nature America, Inc.
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IV.
Reading Materials
F. Articles for Jeffery J. Puschell:
Earth from Space:
Weather Forecasting and Climate Monitoring
10.1117/2.1201410.005608
An improved satellite imager
for year-round Arctic monitoring
Jeffery Puschell
Highly sensitive visible/near-IR imagers in elliptical orbits provide
frequently updated information on Arctic weather and sea ice conditions, even through the long polar night.
Routine satellite monitoring of the Arctic is critical to a host
of environmental applications. Surveillance enables weather
forecasting and studies of climate change, sea ice conditions,
and natural disasters such as volcanic eruptions that affect commercial activities and transportation. However, coverage of the
region by current space-based imaging systems is insufficient.
Imagers onboard traditional geosynchronous Earth orbit (GEO)
environmental satellites, such as the US’s Geostationary
Operational Environmental Satellite and the European Meteosat,
image the full Earth disk as seen from the satellites’ assigned
longitude every 15–30 minutes, but they provide poor coverage
of high latitudes, and cannot reach the center of the Arctic.
Imaging radiometers onboard the other major type of traditional
environmental satellite—those in sun-synchronous polar orbits
that revisit the Arctic approximately every 100 minutes—do not
always cover the entire region on every pass. These limitations
reduce the systems’ effectiveness for monitoring rapidly changing environmental conditions. We need satellites that provide
continuous coverage of the Arctic and that host instruments with
image refresh rates similar to, or better than, those of GEO
systems.
We can meet these requirements using compact, wide-field-ofview (18◦) imagers that operate onboard satellites in a highly
elliptical orbit (HEO). These collect continuous multispectral,
high-sensitivity visible and near-IR Arctic imagery both day and
night. We conceived such imagers based on the remarkable and
unprecedented success of an instrument known as the Visible IR
Imaging Radiometer Suite (VIIRS) operating onboard the Suomi
National Polar Partnership satellite. We are currently developing
a second VIIRS flight unit for the National Oceanic and Atmospheric Administration/NASA Joint Polar Satellite System.
VIIRS includes a high-sensitivity, day-night band (DNB)1 that is
panchromatic (sensitive to all visible colors) and collects highly
Figure 1. Images from the Visible IR Imaging Radiometer Suite
(VIIRS) Day-Night Band (DNB) system of Alaska and the Chukchi
and Beaufort Seas taken under moonlight. DNB provides high-contrast
imagery even under the low thermal contrast conditions prevalent in
the Arctic winter. (Image reproduced with permission from CIRA: the
National Oceanic and Atmospheric Administration Cooperative Institute for Research in the Atmosphere at Colorado State University.)
detailed imagery of the Arctic even under low light levels (see
Figure 1). VIIRS DNB imagery has vastly superior information
content compared with emissive or thermal IR imagery collected
at the same time under the very low thermal contrast conditions
that occur frequently in the Arctic during winter (see Figure 2).
The imagery is enabling significant improvements in forecasting
weather and sea ice changes.
Our HEO day-night imager (HDNI) concept would use this
technology to collect wide-dynamic-range imagery beyond the
Continued on next page
10.1117/2.1201410.005608 Page 2/3
Figure 2. VIIRS imagery in the MI5 spectral band (left) and the DNB (right) of the western Chukchi Sea. Note how the sea ice structure and other
surface detail so readily apparent in the DNB image is not visible at all in the thermal IR image. (Image reproduced with permission from CIRA.)
VIIRS DNB, with spectral coverage (three color, versus single
broad band), radiometric sensitivity, and spatial resolution that
are better than the DNB. Our approach offers a full Arctic
coverage time of 10s at apogee, and a refresh time of 5 minutes
instead of 100 or more for a sun-synchronous polar-orbiting
imager. HDNIs can produce multispectral visible/near-IR
imagery (RGB or true color) both day and night, with
higher-contrast, higher-resolution imagery (750m at apogee)
than existing and planned IR sensors. The dynamic range extends from the brightest clouds, ice, and snow to reflected moonlight from open water, thereby enabling surface discrimination
even under low light and very low thermal contrast conditions.
Therefore, the system can provide unique information about
the dynamic Arctic environment, improving weather forecasting and routine monitoring of ice conditions, human activity,
and natural disasters. Rapidly refreshed HDNI data would
result in frequent updates to key environmental products, such
as cloud and surface imagery, ice, and open water distribution,
including real-time maps of where leads are opening and new
ice is forming, vector ice motion, and vector polar winds from
cloud motion.
Furthermore, the HDNI’s compact sensor design makes it
ideal for deployment as a hosted payload or as the primary
payload on a small satellite. The design, described in more
detail elsewhere,2 offers several advantages over scanning sensors currently used or planned for use in geosynchronous and
polar orbit, including significantly smaller size, lighter weight,
better sensitivity, and more rapidly updated imagery. The largeformat 2D detector arrays used in HDNIs enable a wide-field-ofview imager that could cover the entire Arctic in one frame, plus
most of the Northern Hemisphere as seen from the satellite.
We could implement HDNIs in a wide variety of highly
elliptical orbits. For example, we could deploy the imagers in a
constellation of two satellites in identical 12-hour HEO orbits,
sharing the same orbital plane with a temporal offset of 6
hours, as described in Trishchenko and Garand.3 This twosatellite HEO constellation would provide continuous coverage
of the Arctic, because each satellite moves relatively slowly near
apogee (39,863km above Earth’s surface) enabling it to dwell
over the Arctic for hours.
Furthermore, the imager should be able to detect human activity in the Arctic and elsewhere, based on demonstrated VIIRS
DNB performance. For example, in Figure 1 it is easy to see city
lights along the North Slope of Alaska. Likewise, in other VIIRS
DNB frames, natural gas flares and lights from fishing boats
show up clearly. This application of HDNI imagery may become
increasingly important over time, as development of the Arctic
continues.
In summary, persistent satellite observations are essential
for monitoring and understanding Earth’s environmentally
Continued on next page
10.1117/2.1201410.005608 Page 3/3
sensitive and rapidly changing Arctic region. Compact
wide-field-of-view imagers aboard satellites in HEO could be
positioned over the Arctic and collect multispectral, widedynamic-range visible and near-IR imagery with sensitivity
similar to that of the VIIRS DNB in sun-synchronous polar
orbit. These imagers provide high-contrast visible-wavelength
imagery even through the long polar night. Rapidly refreshed
HDNI data would result in frequent updates, and the relatively
small size of HDNIs makes them easy to deploy. We look
forward, in the future, to the possibility of building and flying
HDNIs as part of commercial or government systems.
References
1. S. D. Miller, W. Straka, III, S. P. Mills, C. D. Elvidge, T. F. Lee, J. Solbrig, A. Walther, A. K. Heidinger, and S. C. Weiss, Illuminating the capabilities
of the Suomi NPP VIIRS Day/Night Band, Rem. Sens. 5, pp. 6717–6766, 2013.
doi:10.3390/rs5126717
2. J. J. Puschell, D. Johnson, and S. Miller, Persistent observations of the Arctic from
highly elliptical orbits using multispectral, wide field of view day-night imagers, Proc.
SPIE 9223, p. 922304, 2014. doi:10.1117/12.2064912
3. A. P. Trishchenko and L. Garand, Spatial and temporal sampling of polar regions
from two-satellite system on Molniya orbit, J. Atmos. Ocean. Technol. 28, pp. 977–992,
2011.
Author Information
Jeffery Puschell
Raytheon
El Segundo, CA
Jeffery Puschell is a principal engineering fellow and has
more than 30 years of experience developing IR and visiblewavelength systems for research and operational applications in
remote sensing and optical communication. He has authored or
coauthored more than 130 technical papers.
c 2014 SPIE
Environmental Monitoring
by Jeffery J Puschell
134 • ME TEOROLOGICAL TECHNOLOGY INTERNATIONAL AUGUST 2013
BETTER
WEATHER
AHEAD
A look at the future
of global weather and
climate forecasting
With Suomi NPP’s Visible Infrared Imager Radiometer
Suite, meteorologists are discovering a new tool for
improving the accuracy of their predictions
or more than 50 years, the Earth
has been observed from space using
instruments on board dedicated
environmental remote sensing satellites.
These satellites have changed the world by
providing continuous global observations
that make it possible to anticipate severe
weather events and provide more accurate
routine weather forecasts, which in turn
helps protect property, save lives and sustain
economic productivity.
Since the first weather satellite, TIROS-1
(Television InfraRed Observation Satellite-1),
launched in 1960, space-based sensing
technology has improved from television
cameras providing fuzzy images of cloud
formations to visible-infrared
spectroradiometers that provide highly
detailed information about the Earth’s
atmosphere and surface. Measurements
made possible by an emerging generation of
new technology instruments are vital to
understanding the complex connections
across the planet driving weather, biological
productivity and climate conditions.
The NOAA/NASA Suomi National
Polar-orbiting Partnership (Suomi NPP)
satellite, launched in 2011, is the latest
development in this 50 year-plus
progression of systems that has
revolutionized our perception and
understanding of the Earth. Suomi NPP,
named for Professor Verner Suomi of the
University of Wisconsin, who flew the first
space-based meteorological experiment in
1958, is the precursor to the Joint Polar
Satellite System (JPSS), the next-generation
operational polar-orbiting US system. JPSS
replaces NOAA’s Polar-orbiting Operational
F
An infrared false-color image taken on October
26, 2012 (below), emphasizes the high clouds
and upper-level outflow near Tropical Sandy’s
center, while the high spatial resolutions of the
VIIRS instrument permits the analysis of
gravity waves propagating out from the center,
as well as the overshooting tops of deep
convective towers that confirm the predicted
intensification of then Tropical Storm Sandy
into a hurricane. The second is a true color
image captured on October 28, 2012 as the eye
of the storm approaches landfall
(Photos: NOAA/NASA)
Environmental Satellite (POES) system,
which traces its legacy back to TIROS, and
the NASA Earth Observing System in orbit
since the late 1990s. JPSS will operate as
part of a constellation of polar-orbiting
environmental satellites that also includes
the current and next-generation EUMETSAT
operational polar orbiting satellites and
Defense Meteorological Satellite Program
(DMSP) satellites.
A single instrument built by Raytheon,
called the Visible Infrared Imager
Radiometer Suite (VIIRS), is the primary
source for 22 of the 38 environmental data
products to be delivered by JPSS, directly
contributing to weather and climate
forecasting and monitoring of sea surface
temperature, ocean color, land use, biomass
fires, aerosols and cloud-top properties.
This next-generation sensor provides
highly accurate and precise measurements
of light radiated by the Earth at visible
through thermal infrared wavelengths.
Incorporating a modular, flexible
design architecture, VIIRS capability
can be adapted to future mission
needs for the next 20 to 30 years,
implementing lessons learned and
responding to new requirements based
on the existing, proven design.
Improving upon legacy technology
Beginning with the first flight unit (F1)
aboard Suomi NPP, and continuing with
future JPSS spacecraft, VIIRS replaces and
improves on four sensors: the Moderateresolution Imaging Spectroradiometer
(MODIS), the Raytheon-built keystone of
NASA’s Earth Observing System, in flight
ME TEOROLOGICAL TECHNOLOGY INTERNATION AL AUGUST 2013 • 13 5
Monitoring the Arctic during ‘polar darkness’ with the VIIRS day-night band. (Photo: NASA)
since 1999; the Advanced Very High
Resolution Radiometer (AVHRR), operating
on board the NOAA Polar Operational
Environmental satellites since 1978 and on
the more recent EUMETSAT Meteorological
Operational (MetOp) satellites; the
operational line scanner (OLS), on board
DMSP satellites since 1976; and the
Sea-viewing Wide Field-of-view Sensor
(SeaWiFS), also built by Raytheon, which
provided ocean color measurements with
unprecedented fidelity for more than 13
years aboard the Orbview-2 satellite.
VIIRS offers major breakthroughs in
environmental remote sensing performance.
Its 22 spectral bands provide four times
better spectral coverage than AVHRR,
thereby enabling new agricultural, climate,
disaster monitoring, public health and
weather data products. VIIRS also offers at
least three times better spatial resolution
than AVHRR and MODIS at end-of-scan,
giving sharper imagery over a much greater
area. A wider imaging swath (3,000km)
eliminates coverage gaps at the equator
during a single day of observation. A fully
calibrated day/night band, with 100 times
more sensitivity than OLS, improves
night-time weather forecasting.
Innovative design
A key to the success of the VIIRS design is
a rotating telescope assembly that can
simultaneously meet a diverse set of
requirements for multispectral imaging,
spectroradiometry and low-light day/night
observations. Advantages of the rotating
telescope design relative to scan
mirror-based systems include better control
of stray light; smaller range in angle of
incidence of light on the fore optics, to
reduce image distortion; immunity to image
rotation as the scan moves out from nadir;
and better protection from contamination
and degradation over time because all
optical elements are deep inside the
instrument housing.
The rotating telescope assembly is
followed by a fixed telescope along with
other back-end optics that image the scene
and separate light onto three focal planes
with filters that define each spectral band.
13 6 • ME TEOROLOGICAL TECHNOLOGY INTERNATIONAL AUGUST 2013
A cryoradiator radiates heat from the
infrared detector arrays to deep space to
maintain a stable detector operating
temperature as low as 78K.
The focal plane interface electronics
carry signals from the detector arrays to the
externally mounted electronics module
(EM). The EM synchronizes the rotating
telescope assembly with a rotating flat
mirror to make it possible to image the
scene onto the detector arrays without
image rotation. The EM also provides
onboard processing of detector samples
to enable a nearly constant pixel size across
the entire scan, data compression,
processing of operational data, and
formatting of the data into the Consultative
Committee on Space Data Systems
(CCSDS) format. The EM communicates via
a databus with the spacecraft, to provide
VIIRS operational data and telemetry, and
to receive commands, spacecraft telemetry
and software uploads. A fault-tolerant
design enables long mission life.
VIIRS has an onboard calibration
subsystem consisting of a carefully
stabilized blackbody source to provide
a reference signal for the emissive infrared
bands, and a diffuser to provide a
reference for bands dominated by reflected
sunlight. VIIRS includes a monitor to
detect any changes in the optical
characteristics of the solar diffuser over
time. The VIIRS calibration subsystem has
a rich MODIS heritage – a key to
maintaining continuity with data from the
MODIS instruments onboard the NASA
Earth Observing System Terra and
Aqua satellites.
The two images on the opening page
show two views of Hurricane Sandy. The
first, on the left, is an infrared false-color
image taken on October 26, 2012,
emphasizes the high clouds and upper-level
outflow near the storm’s center. The high
spatial resolution of the VIIRS instrument
permits the analysis of gravity waves
propagating from the center, as well as the
overshooting tops of deep convective towers
that confirm the predicted intensification of
the then tropical storm into a hurricane. The
second figure (on the right) is a true-color
image captured on October 28, 2012 as the
eye of the storm approached landfall.
Results show the VIIRS sensor validates
its fundamental design architecture by
delivering environmental data products with
unprecedented completeness.
VIIRS architecture, from photon collection to data generation
Night vision
One advance that has received particular
attention is the VIIRS day-night band
(DNB), a wide dynamic range,
panchromatic spectral band that collects
useful visible wavelength imagery with
illumination ranging from full sunlight
down to air glow and aurorae. It is sensitive
enough to pick up light from single ships at
sea at night.
Meteorologists in Alaska are finding
VIIRS DNB imagery to be an important
new tool for operational weather
forecasting. The DNB is remarkably useful
for characterizing clouds, detecting snow,
ice and fog, and tracking hazardous
weather patterns during the long Alaskan
winter, when visible wavelength imagery
from other systems is severely limited.
Likewise, weather forecasters in the
contiguous USA and elsewhere are finding
that VIIRS DNB data enables clear views of
weather events throughout the night,
improving prediction accuracy.
As VIIRS F1 continues to perform well
on board Suomi NPP, providing high-quality
visible/infrared imaging spectroradiometry
with unprecedented clarity and completeness,
F2 is being built at Raytheon’s facility in El
Segundo, California. The sensor is on track
for delivery in 2014 and a scheduled launch
on board the first JPSS satellite in 2017.
As AVHRR and MODIS take their
place in the history of space-based
environmental remote sensing, VIIRS will
continue to expand the record of
environmental data that scientists use to
understand the Earth, enhance weather
forecasting and track climate conditions
for future generations. z
VIIRS F1 and F2 instrument characteristics with image of F1 integrated onto the Suomi NPP spacecraft
(Picture: Ball Aerospace)
Jeffery J Puschell is the principal engineering fellow at
Raytheon Space and Airborne Systems, based in the USA
ME TEOROLOGICAL TECHNOLOGY INTERNATION AL AUGUST 2013 • 137
IV.
Reading Materials
G. Articles for Professor Angela V. Olinto:
Extreme Universe Space Observatory
at the Japanese Module
ADVERTISEMENT
Permanent Address: http://www.scientificamerican.com/article/cosmic-ray-telescope-flies-high/
Space » Scientific American Volume 311, Issue 5 » Advances
Cosmic-Ray Telescope Flies High
The new detector passes tests involving a helicopter, balloon and lasers
Oct 14, 2014 | By Debra Weiner |
Cosmic rays, traveling nearly at the speed of light, bombard Earth from all
directions. The electrically charged particles are the most energetic component of
cosmic radiation—yet no one knows where they come from.
Astrophysicists speculate that high-energy cosmic rays may have emerged from
supermassive black holes in faraway galaxies or possibly from decaying particles
from the big bang.
Whatever their origin, these rays crash into Earth’s atmosphere about once per
square kilometer per century. The impact produces an air shower of tens of billions
of secondary, lower-energy particles that in turn excite nitrogen molecules in the
atmosphere. The interactions produce ultraviolet fluorescence that lights up the air
shower’s path. Scientists are trying to use such paths to measure the direction and
energy of cosmic rays and reconstruct their trajectories back millions of light-years
into space to pinpoint their source.
Seeing these extreme events is rare. Earth-based observatories can spot cosmic- ray
collisions only if they occur directly above the detectors. The Pierre Auger
Observatory in Argentina, which houses the world’s largest cosmic-ray detector and
covers an area roughly the size of Rhode Island, records about 20 extreme-energy
particle showers a year.
Hoping to improve the odds of observing the rays, a team of scientists from 15
nations came together more than a decade ago and designed a cosmic- ray telescope
for the International Space Station (ISS). On the Japanese Experimental Module, the
Extreme Universe Space Observatory (JEM- EUSO) will record ultraviolet emissions
with a wide-angle, high-speed video camera that points toward Earth. With such a
large observation area, the camera will see more air showers. The team originally
hoped to launch EUSO in 2006. But troubles on Earth—first the space shuttle
Columbia disaster in 2003, then the Fukushima nuclear meltdown in 2011 and now
the turmoil in Ukraine—have delayed its deployment until at least 2018.
This summer in Timmins, Ontario, scientists tested
the prototype of a new cosmic-ray telescope.
Stephen Rountree
The science, however, marches onward. In August the team launched a prototype of
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the telescope 38 kilometers into the stratosphere onboard a helium- filled balloon.
For two hours, researchers followed below in a helicopter, shooting a pulsed UV laser
and LED into the telescope’s field of view. The test was a success: the prototype detected the UV traces, which are similar to the
fluorescence generated by extreme energy cosmic-ray air showers. In 2016 astronauts will transport a shoebox-size prototype called
Mini-EUSO to the ISS and see how it fares at the altitude of the full mission.
This article was originally published with the title "Catching Some Rays."
Buy this digital issue or subscribe to access other articles from the November 2014 publication.
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