AGN jets population studies from high cadence multi

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Physics of extragalactic
plasma elements
through high cadence, multi-frequency linear and circular radio polarisation monitoring of blazars
Ioannis Myserlis & Emmanouil Angelakis
Collaborators
A. Kraus, L. Fuhrmann, V. Karamanavis, J. A. Zensus Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
Source: COSMOVISION
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the RadioPol program:
APEX
30 m IRAM
100 m Eﬀelsberg
part of the f-gamma program: ➡ almost
➡ 2.64
90 mostly Fermi sources
- 142 GHz at 10 frequency steps circularly polarized feeds ➡ LP
at 2.64, 4.85, 8.35, 10.45 and 14.6
➡ CP
at 2.64, 4.85, 8.35, 10.45, 14.6, 23.05
➡ mean
cadence 1.3 months
➡ uncertainty
0.1 (polarization degree units)
Angelakis et al. 2010, astro-ph.CO/1006.5610
Fuhrmann et al. 2007, 2007, AIP Conf. Series, Vol. 921, 249–251
I.Myserlis | Max-Planck-Institut für Radioastronomie | Strasbourg, May 11-12, 2015
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the RadioPol program:
2007.0
45
2008.0
2009.0
2010.0
2011.0
2012.0
2013.0
2015.0
2.64 GHz
4.85 GHz
8.35 GHz
10.45 GHz
14.60 GHz
23.05 GHz
32.00 GHz
42.00 GHz
86.00 GHz
142.33 GHz
228.93 GHz
J2253+1608, 3C454.3
40
35
Flux Density (Jy)
2014.0
30
25
20
15
10
5
0
54000.0
54500.0
55000.0
55500.0
56000.0
56500.0
57000.0
MJD
part of the f-gamma program: ➡ almost
➡ 2.64
90 mostly Fermi sources
- 142 GHz at 10 frequency steps circularly polarized feeds ➡ LP
at 2.64, 4.85, 8.35, 10.45 and 14.6
➡ CP
at 2.64, 4.85, 8.35, 10.45, 14.6, 23.05
➡ mean
cadence 1.3 months
➡ uncertainty
0.1 (polarization degree units)
Angelakis et al. 2010, astro-ph.CO/1006.5610
Fuhrmann et al. 2007, 2007, AIP Conf. Series, Vol. 921, 249–251
3
See also our poster
population studies of fermi AGN jets with
multi-frequency radio linear and circular, optical linear
polarisation monitoring
I. Myserlis1, E. Angelakis1, V. Pavlidou2, D. Blinov2, L. Fuhrmann1, J. A. Zensus1 and the F-GAMMA and RoboPol collaborations
1 Max
Planck Institute for Radio Astronomy, Bonn, Germany 2 University of Crete, Heraklion, Greece
Abstract
Radio polarisation properties
Radio polarisation of different classes
The radio and optical emission of AGN jets is attributed to
the incoherent synchrotron processes and hence intrinsically polarised. Here we present a population study that is
based on high cadence, radio multi-frequency linear and
circular polarimetric data and optical (R-band) linear polarisation.
Here is a summary of the radio linear polarisation:
here is how FRSQs differ from the BLLacs at 4.85 GHz
Optical polarisation properties of F-GAMMA
sources
For the subset of F-GAMMA sources included in the
RoboPol sample we are getting the following.
The ultimate goal is to study macroscopic characteristics
of the jet like (a) the jet magnetic field topology, (b) the
composition of the emitting plasma, (c) correlation with
physical properties of the central engine (black hole mass
and spin), acceleration rate and accretion disk luminosity
and (d) correlation with source class. Here we provide a
brief introduction to the project.
Dataset
radio bands:
the radio multi-frequency dataset is from the F-GAMMA
program (Angelakis et al. 2010, astro-ph.CO/1006.5610,
Fuhrmann et al. 2007, 2007, AIP Conf. Series, Vol. 921,
249–251) and includes:
‣
‣
‣
‣
‣
‣
‣
almost ~80 mostly Fermi blazars
total power at 10 frequencies in the range: 2.6 - 142 GHz
LP at 2.64, 4.85, 8.35, 10.45 and 14.6
CP at 2.64, 4.85, 8.35, 10.45, 14.6, 23.05
mean cadence ~1. months
uncertainty 0.1 (polarisation degree units)
dataset covers 8 years
frequency
(GHz)
fraction of
polarised
sources
(%)
mean
polarisation
degree
(%)
median
polarisation
degree
(%)
2.64
89
2.8
2.3
4.85
79
3.0
2.4
8.35
88
3.0
2.4
10.45
66
3.1
2.6
Radio polarisation pipeline
The radio polarisation data reduction includes a series of
steps necessary for reaching high precision particularly
important for CP where values lower than 1% are expected. Our pipeline include
‣
‣
‣
‣
almost 65 Fermi blazars and 15 gamma-quiet sources
cadence between 3 and 0.3 days
photometry down to 0.01 mag
polarimetry with SNR: 10:1 of 3% polarised source of R=
17.5 mag in 40 minutes
‣ dataset covers 2 seasons
f-gamma project
The degree of linear polarisation at 4.85 and R-band for
the FSRQs and BLLACS separately
For the circular polarisation we find:
optical:
the optical dataset includes R-band linear polarisation and
is from the RoboPol program (King et al. 2014, MNRAS,
442, 1706, Pavlidou et al. 2014, MNRAS, 442, 1693) and
includes:
There is a total overlap of 43 sources which comprises
the base for this study.
here is the dependence of ml on redshift for FRSQs and
BLLacs at 4.85 GHz
‣ instrument model subtraction
‣ full stokes Mueller Matrix correction (“4x4” problem solution
frequency
(GHz)
fraction of
polarised
sources
(%)
mean
polarisation
degree
(%)
median
polarisation
degree
(%)
4.85
6.4
0.5
0.4
8.35
6.4
0.6
0.5
The return of this effort is:
‣ LP degree with SNR of order of 30
‣ CP degree with SNR 5 for a 0.5 % polarised source
Summary & Outlook
The available datasets are adequate for gaining insight on
the physical conditions in AGN jets at the emission sites of
radio and optical bands. The aim is be to understand: (a)
the dominant B-field component in the two regions and its
strength (b) what is the low energy particle content of the
jets and possibly the exact jet composition (c) distinctions
between FSRQs and BLLacs. On that basis of an evolutionary model (e.g. Marscher & Gear 1985, ApJ, Vol. 298,
114-127) we are investigating the jet conditions that may
reproduce best the observed temporal behaviour of variability events (Myserlis et al arXiv:1401.2072).
robopol project
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incoherent synchrotron:
intrinsically polarised
credit: S. Kiehlmann
relativistic magnetized plasma laboratories
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Spectrdal index a
determines:
α = +2.5
α ≃ —0.7
νm
➡ νV = 0.49 νm
➡ νQ = 0.44 νm
➡ ml ≃ 72 %
➡ mc ≃ 11 %
➡
s+1
s + 73
EVPA perpendicular
to projected B-field
linear component:
EVPA parallel to
projected B-field
νQ=0.44 νm ➝ τ ≃ 7
3
6s + 13
⌫Q
⌫
1
2
circular component:
νV=0.49 νm ➝ τ ≃ 5
⌫
1
2
⌫V
Pacholczyk Pergamon Press, 1977
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EVPA flip
ml → 0
mc → 0
S → Smax
frequency, time
optical depth
optical depth
M. Turler et al. 2000; Marscher & Gear, 1985ApJ...298..114M
http://www.isdc.unige.ch/~turler/jets/
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2015.7
thin → THICK
THICK → thin
thin → THICK
→ thin
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Myserlis, Angelakis et al. in prep.
From qualitative to quantitative
Our model:
Polarized radiative transfer solutions
Parameters:
‣ Element size & number density
‣ Angle w.r.t. B-field
‣ B-field strength
‣ Projected B-field position angle
‣ Shock front compression
‣ Angle w.r.t. shock front
270 d
600 d
140 d
240 d
Model setup:
‣ component 1
‣
components 2: follows the entire path
after 1000 d ‣
quiescent of ~0.05 Jy ‣
B uniformity: =0.2 (20%)
‣
identical power
‣
B-field is unidirectional for the 2
components at the fiducial angle of -10o
optical depth
• adiabatic ~150 d and fast adiabatic
~240 d
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optical depth
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Summary & Outlook
➡a
rich dataset of polarization data is available (RadioPol / F-GAMMA): ➡
90 most fermi bright sources
➡
8 years ➡
cadence 1 — 1.3 months
➡
8 frequencies
➡ within
the framework of traveling shocks we can reproduce the observed behaviors
with a newly developed model:
➡
2 components on a similar evolutionary path
➡
equal power
➡
20% uniform field
➡ within
➡B
this framework we can learn: field strength and uniformity ➡ Opacity
➡ the
and linear scale evolution of the variability producing emission elements
jet composition (e+- vs e - ion) from the enhancement of polarization (Jones 1988)
➡ mc/mi
can tell you the FR conversion and rotation coeﬃcients and estimate the
thermal content of the plasma ➡ Stay
tuned!
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thank you
Ioannis Myserlis & Emmanouil Angelakis
Max-Planck-Institut für Radioastronomie, Auf dem Huegel 69, Bonn 53121, Germany
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AGN jets population studies from high cadence multi

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