Nearby Galaxy Evolution with Deep Surveys:

Transcription

Nearby Galaxy Evolution with Deep Surveys:
Studying galaxies at 1<D<100 Mpc
Eric Peng
Peking University
Monday, December 5, 2011
Why 1 < D < 100 Mpc?
• Need to leave the Local Group for a representative
sample of galaxies to study
• The Coma Cluster (100 Mpc) is the nearest truly
massive galaxy cluster
• Much of what we know about the detailed properties of
galaxies is from this distance range (internal stellar
populations, kinematics, star formation regions, etc).
D
5 kpc 10 pc
(Mpc)
TRGB+2 GCLF
(I)
mean(g)
milestone
0.8
22’
2.7”
22.4
17.3
M31, nearest MW analog
4
4.3’
0.5”
26.0
20.9
NGC 5128
nearest massive E (pec)
16.5
1.0’
0.13”
27.1
24.0
Virgo Cluster
100
10”
0.02”
31.0
27.9
Coma cluster
Galaxies that are “too far” and “too near”
• (Only) partially resolved into stars, HII regions, substructure
• Large, truly extended sources (many arcmin)
• Complicates observing strategy, standard data reduction
and analysis pipelines
• Targeted observations are okay, but become “special
cases” in large surveys.
D
5 kpc 10 pc
(Mpc)
TRGB+2 GCLF
(I)
mean(g)
milestone
0.8
22’
2.7”
22.4
17.3
4
4.3’
0.5”
26.0
20.9
NGC 5128
16.5
1.0’
0.13”
27.1
24.0
Virgo Cluster
100
10”
0.02”
31.0
27.9
Coma cluster
Virgo central galaxy, M87 (CFHT)
Globular Cluster Systems
Globular clusters and satellite galaxies
z=12
565
a few Gyr, creating the inner Galactic dark halo and its associated
old stellar population.
With an efficiency of turning baryons into stars and globular clusters of the order of f ∗ = 10 per cent, we successfully reproduce
the total luminosity of the old halo population and the old dwarf
spheroidal satellites. The fraction of baryons in dark matter haloes
above the atomic cooling mass at z = 12 exceeds f c = 1 per cent. A
normal stellar population with a Salpeter-type initial mass function
emits about 4000 hydrogen-ionizing photons per stellar baryon. A
star formation efficiency of 10 per cent therefore implies the emission of 4 000 × f ∗ × f c ∼ a few Lyman-continuum photons per
baryon in the Universe. This may be enough to photoionize and
drive to a higher adiabatic vast portion of the intergalactic medium,
thereby quenching gas accretion and star formation in nearby lowmass haloes.
• GCs form early in the evolution of galaxies
• Trace early, major epochs of star formation
• Simple stellar populations (mostly)
• Observable out to >100 Mpc, massive systems
3 CONNECTION TO GLOBULAR CLUSTERS
A N D H A L O S TA R S
z=0
The globular clusters that were once within the merging protogalaxies are so dense that they survive intact and will orbit freely within
the Galaxy. The surviving protogalaxies may be the precursors of
the old satellite galaxies, some of which host old globular clusters
such as Fornax, whose morphology and stellar populations are determined by ongoing gravitational and hydrodynamical interactions
with the Milky Way (e.g. Mayer et al. 2005).
Recent papers have attempted to address the origin of the spatial
distribution of globular clusters (e.g. Parmentier & Grebel 2005;
Parmentier & Gilmore 2005). Most compelling for this model and
one of the key results in this paper is that we naturally reproduce the
spatial clustering of each of these old components of the galaxy. The
radial distribution of material that formed from >2.5σ peaks at z >
12 now falls off as ρ(r ) ∝ r −3.5 within the Galactic halo – just as the
observed old halo stars and metal-poor globular clusters (cf. Fig. 2).
6
10
dEs
stellar halo ~ r–3.5
globular clusters
dwarf galaxies
5
10
Figure 1. The high-redshift and present-day mass distribution in a region
that forms a single galaxy
in a hierarchical
CDM Universe. The upper panel
Moore
et al (2006)
shows
the
density
distribution
at
a
redshift
z
= 12 from a region that will form
4
10
all
3
10
gEs
The Properties of Globular Cluster Systems
Specific Frequency: number of
GCs normalized to MV=-15
SN = NGC 10 0.4(MV+15)
Puzzle:
Globular cluster formation
efficiency is not constant across
galaxy mass
Peng et al. (2008)
Globular Clusters in Virgo Cluster dEs:
The Role of Environment
• Dwarfs only: Mz > -19
• SN vs clustercentric distance
• dEs with high GC fractions are within
Dp < 1 Mpc
• dEs within 100 kpc, stripped of GCs
Peng et al. (2008)
The Evolution of Massive Galaxies
DeLucia & Blaizot (2007)
Observations show little mass
evolution in BCGs with
redshift
•
In massive clusters, N-body
simulations predict that
“intracluster” light dominates the
light of the BCG
• Prediction: Strong correlation
between ICL fraction and cluster
mass
• Intracluster Globular
Clusters (IGCs) should
accompany ICL, and can be
easier to see
Purcell, Bullock & Zetner (2007)
HST/ACS Coma Treasury Survey (Carter et al 2008)
Globular clusters easily detected!
HST/ACS Coma Treasury Survey (Carter et al 2008)
GC spatial distribution in cluster core
• NGC (R<520kpc) = 70,000
• “Intergalactic” GCs = 47,000
• Implied ICL: 27 mag/arcsec2
• ~2500 disrupted dEs at MV=-16
• BH-BH binaries from GCs ->
Detectable source of
gravitational waves? (Work in
progress with Jonathan
Downing)
Coma core GC distribution
Peng et al. (2011)
~70% of GCs in N4874+IGC system are IGCs, ~30-45%
of GCs in the core are IGCs
Consistent with ICL measurements (Gonzalez et al) and
simulations (Purcell et al)
• CFHT Large Program
(2009-2012)
• 104 sq. deg in ugriz
• u*g’~26, r’i’z’~25
• PI: L. Ferarrese
• Galaxies, globular
clusters, foreground
halo, background
clusters
• “Sandbox” for future
surveys
The Next Generation Virgo Survey
J.-C. Cuillandre
NGVS Status (2009-2011)
IGCs in the Virgo Cluster?
ICL observations
• LSB light (Mihos)
• Planetary nebulae (Arnaboldi,
Okamura, Feldmeier)
• Best galaxy cluster for GC
observations
Mihos et al (2006)
M86
M89
M60
M84
Virgo globular
cluster spatial
distribution
Can we estimate the
IGC fraction in Virgo?
MMT/Hectospec
• 6.5 nights (PI: E. Peng)
• ~1000 confirmed GC velocities
• confirmed IGCs
M49
Preliminary IGC fraction
ranges from ~0-40%
depending on chosen
background region.
Need careful treatment of
Galactic foreground.
Virgo and the Galactic Foreground
V. Belokurov
Virgo and the Galactic Foreground
Virgo
Overdensity
Virgo GCs
Sgr MSTO
Resolving Virgo GCs in the NGVS
With 0.6” image quality:
• Many bright GCs in Virgo are resolved
• Star-galaxy separation becomes difficult at i>24, ~2 mag
above photometric limit.
Star-GC-galaxy selection
Point sources
Background
galaxies
GCs
ugi selected point sources
Foreground stars
The inclusion of u-band is extremely helpful for MW studies
Overlap regions
rh in g band
rh in i band
Sizes of Stellar Systems
• Measuring sizes of stellar
systems is important for
understanding them
• Globular clusters are among the
smallest stellar systems
0.5” seeing
Coma
Virgo
• ELTs+AO may not significantly
improve survey speed for GCs in
nearby galaxy clusters for certain
applications
• HST and current ground-based
facilities can already do a lot
HST
30m ELT
Misgeld & Hilker (2011)
The Telescope Access Program (TAP)
CFHT
3.6m
Palomar
5m
Magellan
2x6.5m
MMT
6.5m
Eric Peng, Shude Mao, Suijian Xue, Xiaohui Fan, Xiaowei Liu, Junxian Wang, Zhongxiang Wang, Jiasheng
Huang, Lin Yan, Haojing Yan, Jiansheng Chen, Paul Ho, Fred Lo
Gang Zhao, Timothy Beers, Yu Gao, Qiusheng Gu, Raja Guhathakurta, Lei Hao, Lihwai Lin, Shengbang Qian,
Hongchi Wang, Weimin Yuan
The Goals for TAP
•
Promote excellent PI-led science. Do this in conjunction with other domestic
initiatives (e.g., Lijiang 2.4m).
•
Build a user community for current and future projects (Dome-A, TMT, etc).
•
Build our international competitiveness. We eventually need to be able to
compete on the “open market” in observational astronomy.
•
To increase our ability to build instrumentation, manage projects, and
contribute “in-kind” to future international facilities.
TAP Status
•
CFHT (3.6m, 15 nights/year), Palomar Hale (5m, P200, 20 nights/year)
•
MMT (6.5m, 10 nights/year), Magellan (6.5m x 2, 2-4 nights/year)
•
TAP will be for 3 years (2011-2014)
•
2011B: Oversubscription:1.5-3, 15 programs
•
2012A: Oversubscription: 1.5-3, 14 programs
•
Next deadline, late-March, 2012 for 2012B
TAP and the Community
The 1st TAP Workshop for Optical-IR Astronomy in China
PKU/KIAA, 16-17 Feb 2011
We held our first TAP workshop at
PKU/KIAA to introduce the program to
the community.
• ~100 participants from all over China
• International visitors from TAP
observatories
• Discussions on joint science programs
TAP Workshop, 16-17 Feb 2011
Next TAP Workshop being planned for Feb, 2012.
Call for new CFHT Large Programs (2013-2016), deadline Feb 28, 2012
The Next Generation CFHT
(from Pat Côté (HIA) and the ngCFHT Concept Study Team)
The Next Generation CFHT Proposal
• There is an exciting opportunity to capitalize on the need for extensive, wide field,
highly multiplexed, optical/infrared spectroscopy in the coming decade.
• The Next Generation CFHT concept aims to create a new and expanded CFHT
partnership to:
1. replace the present 3.6m primary mirror with a 10m-class (segmented) mirror,
mounted on the existing pier.
2. install a dedicated wide-field (1.5 deg2) multi-object spectrograph that can
simultaneously collect spectra for >3000 sources.
3. do this by ~2020 and immediately begin spectroscopic surveys.
• provide the spectroscopic complement to MegaCam, PS1, Skymapper,
HyperSuprimeCam, ODI, DES, GAIA, LSST, EUCLID and WFIRST.
• ngCFHT should enable focussed science for key targets and/or programs.
Summary
D
(Mpc 5 kpc
)
0.8
22’
10 pc
TRGB+2
(I)
GCLF
mean(g)
milestone
2.7”
22.4
17.3
4
4.3’
0.5”
26.0
20.9
NGC 5128
16.5
1.0’
0.13”
27.1
24.0
Virgo Cluster
100
10”
0.02”
31.0
27.9
Coma cluster
Intergalactic GCs in
Coma cluster
Nearby galaxies
NGVS
GCs in Virgo
Probing Galactic halo:
utility of u-band
Resolving stellar systems
Telescope Access Program

Nearby Galaxy Evolution with Deep Surveys:

Transcription

Similar documents

The Bangles Manic Monday

FC Stars Of MA Boys Junior Academy Northborough

Predation, Mutualism, Commensalism, or Parasitism

DCCC`s Lecture Capture Adventure

the complete writer

Internship Presentation

Newsletter 22 April 2015

Thickett Apartments - Ellipse Communications, Inc

Fall 2013 Activities for Babies to Teens

Download: PDF - biolifejournal