new young radio galaxies from radio to xrays: spectral modeling … · 2010. 6. 28. · about 40%...
TRANSCRIPT
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Collaborators: Rafal Moderski Copernicus Astronomical Center, Warsaw (Poland)
& KIPAC/Stanford, CA (USA)Łukasz Stawarz JAXA, Tokyo (Japan), KIPAC/Stanford, CA (USA),
& Astronomical Observatory, Kraków (Poland) Antonaldo Diaferio Dept. of General Physics & INFN, Torino (Italy) Teddy Cheung NASA/GSFC, Greenbelt, MD (USA) Jun Kataoka Waseda University, Tokyo (Japan) Mitch Begelman JILA University of Colorado, Boulder, CO (USA) Izabela Kowalska Astronomical Observatory, Warsaw (Poland) Stefan Wagner ZAH Landessternwarte, Heidelberg (Germany)
AGN 9 Ferrara, May 2427 , 2009
Young radio galaxies from radio to Xrays: Spectral modeling and clues from the absorption
Luisa Ostorero INAF, Dipartimento di Fisica Generale, and INFN Torino, Italy
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Outline
Introduction
An evolution model for young radio sources
SED modeling of a sample of Xray GPS galaxies
Absorption: NH NHI correlation
Summary and prospects
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About 40% of bright, cmselected radio sources
are compact (subgalactic scale)
display a radio spectrum peaked at ~1 GHz (GPS/CSS)
are as powerful as the extended radio sources: L5 GHz >1025 W/Hz
display an anticorrelation between spectral turnover p and linear size LS:
p ∝ LS0.65
~ 10% : GPS, p=0.510 GHz, LS
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GPS/CSS radio galaxies with CSO morphology
have negligible projection and Doppler effects ⇒ intrinsically very compact and powerful
remarkably resemble a rescaled version of giant radio galaxies(FRII)
are hosted by the most massive earlytype galaxies, with evidence of either starburst activity and/or AGNinduced light; often morphologically disturbed [Snellen+1996;de Vries+2007]
are preferentially located at 0.1≤z≤1 [O'Dea+1991]
are good candidates for being young radioloud AGNs [Philips & Mutel 1982; Murgia+1999; Giroletti+2003;Gugliucci+2005]
Introduction
de V
ries
+ 2
007
■ 3C galaxies GPS galaxies LRGs
V m
ag
Gug
liucc
i + 2
005
redshift
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Debated issuesDebated issues
GPS/CSS galaxies are increasingly detected in the Xray band ⇒ source of the Xrays emission:
accretion disc? ISM? lobes?
[Heinz+1998;O'Dea 2000; Guainazzi+2004, 2006; Vink+2006; Siemiginowska+2008; Tengstrand et al. 2009]
Interaction between jets/lobes and the ISM of the hostgalaxy ⇒ effects on source dynamical/radiative evolution?
⇒ effects on the host galaxy? [Morganti+2004; Vermeulen+2006;Labiano+2007; Holt+2007]
Radio spectra turn over due to absorption effects ⇒ Synchrotronself absorption and/or
freefree absorption?
[Kellermann1966;O'Dea 1991;Bicknell+1997;Begelman 1999; deVries+2009]
Too many “young” sources: ⇒ Short life? Jet disruption? Intermittency?
[Readhead 1996; Alexander 2000; Kaiser & Best 2007; Reynolds & Begelman 1997;Czerny+2009]
Introduction
4C 12.50 Mor
gant
i +
2004
Chandra
Siem
igin
owsk
a +2
008
O'D
ea 1
998
Num
ber o
f sou
rces
Projected linear size (kpc) Our project: Multiwavelength investigation
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Dynamical evolution
Jet propagating in the ISM of the central, kpcsized region of the galaxy, engulfing and photoionizing NLR clouds [Begelman 1999; Begelman & Cioffi 1989]
Main model parameters:
jet kinetic power : Lj
source linear size: LS
after Begelman & Cioffi 1989
SHOCKED ISM
Stawarz et al. 2008, ApJ, 680, 911
Constraints:
LS
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An evolution model for young radio sources
hotspot's electron distribution
(s1~1.5, s2>3)
lobe's electron energy spectrum
lobe's synchrotron emission
Q() N()
Q =2
PL BPL
Ne()
• Q(): broken powerlaw
Lsyn
Crint
PL BPL
Radiative evolution: lobe synchrotron emission
Hotspots : ultrarelativistic e , Qe() , = 1105
Lobes : Ne() = evolution of Qe() (adiabatic and radiative losses)
Stawarz et al. 2008
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Radiative evolution: absorption mechanisms
SSA ? If Q() =K s
⇒ with x=0.30.36 (s=13) ⇒ flatter than xobs=0.65
⇒ ≪ 1 GHz
⇒ SSA effects not included in our model
FFA ... by the ionized layer of the engulfed clouds [Begelman 1999]
(ISM~const; NLR~rn, n=12)
⇒ absorbed spectrum dependent on “s”
SSA ~ LSx
SSA ~ 0.3Lj,45 LS100 GHz
p ~LS 0.65
L
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Radiative evolution: lobe inverseCompton emission
Photon fields within the lobes:
(1) synchrotron photons
(2) UV radiation from the accretiondisc
(3) FIRMIR radiation from the torus
(4) star light
An evolution model for young radio sources
Stawarz et al. 2008
IC
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Radiative evolution: lobe broadband emission
⇒ Xray emission reproduced ⇒ prediction of ray emission
•
Q(
): b
roke
n po
wer
law
Stawarz et al. 2008
Xrays
An evolution model for young radio sources
Stawarz et al. 2008
LS = 30 pc
LS = 100 pc
LS = 1 kpc
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Selection criteria
GPS galaxies
CD/CSO morphology
Xray spectra available
Sample characteristics
11 GPS galaxies
LS ~ 10 – 400 pc
z ~ 0.076 – 0.99
h,sep ~ 0.25 – 0.40
log(L5GHz[W/Hz]) ~ 25.4 – 27.8
p ~ 0.6 – 8.3 GHz
L210keV ~ 51041 – 5 1044 erg/s (ASCA, XMM, Chandra)
SOURCE
LIST
IERS B0026+346IERS B0108+388IERS B0500+019 IERS B0710+439
PKS 0941080 IERS B1031+567 IERS B1345+125
IVS 1358+624 IERS B1404+286IERS B2128+048 IERS B2352+495
Stan
ghel
lini e
t al.
1997
Pear
son
et a
l. 19
88
SED modeling of a sample of Xray GPS galaxies
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SED modeling of a sample of Xray GPS galaxies
LO et al. 2010, ApJ, 715, 1071
Examples of modeled SEDs
Radio spectra: synchrotron emission from the lobes
Lj = 2 1044 – 4 1045 erg/s freefree absorption
L(
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SED modeling of a sample of Xray GPS galaxies
LO et al. 2010, ApJ
The whole SED sample
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Model parameters results
SED modeling of a sample of Xray GPS galaxies
LO et al. 2010, ApJ
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Model parameters – results
ṁ / ṁEdd=0.026−0.55 !
SED modeling of a sample of Xray GPS galaxies
Czerny et al. 2009
Intermittency
Threshold for accretiondisc instabilities driven by the radiation pressure
[Czerny+2009]
Our estimates of the accretion rate (from LUV, MBH ):
⇒ all our GPSs are intermittent sources
=ṁ / ṁEddthr=0.025
LO et al. 2010 , ApJ
=ṁ / ṁEddthr=0.025
ṁ / ṁEdd=0.026−0.55 !
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Absorption: NH – NHI correlation
Our model: Xray radiation produced in the lobes
• isotropic
• cospatial with the radio emission
⇒ Prediction:
radio and Xray absorbers ( NHI and NH )comparable in individual sources
However, estimates of NHI depends on the assumed “Ts /cf”
Therefore, we first look for an NH− NHI correlation...
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NH− NHI significant correlation appears to be there
NH, NHI measurements available for : 7 / 11 GPS galaxies of our sample 4 additional Xray GPS galaxies
[Tengstrand+2009]
Prob. of no correlation: P
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Increasing Ts /cf can remove discrepancies
In fact, in the AGN environment:
1) TK ~ few 103 K ⇒ Ts ≫100 K (Ts~ TK) [Maloney+1996; List 2001]
2) cf
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Summary
Dynamical/radiative model to study the GPSphase of young radio sources
Expansion of the GPS lobes in the cloudy ISM Synchrotron + IC emission (SSC and EC)
Modeling of the broadband SEDs of a sample of Xray GPSs
opticallythick radio spectra: reproduced with FFA Xray emission: reproduced as lobe's IC radiation
high accretion rates ⇒ source intermittency
Significant NHNHI correlation: Xray/radio cospatiality Possible estimate of Ts/cf
Work in progress
Improvement of the NHNHI statistics: new NHI measurements with the WSRT (with R. Morganti, ASTRON, and A. Siemiginowska, CfA )
Fermi/LAT: ray emission ?
Summary and Prospects
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Thank you !