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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
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
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
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
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
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
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
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
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
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
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
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(
SED modeling of a sample of Xray GPS galaxies
LO et al. 2010, ApJ
The whole SED sample
Model parameters results
SED modeling of a sample of Xray GPS galaxies
LO et al. 2010, ApJ
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 !
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...
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
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
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
Thank you !