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On the spectro-photometric properties of the bulk of Radio-Loud AGN
population
Ranieri D. Baldi1, Alessandro Capetti2
1: SISSA, Trieste2: Osservatorio Astronomico di Torino
Baldi & Capetti 2009, 2010
The fundamental question is:
• Do the classical powerful radio sources, FRI and FRII, provide us with the correct view of AGN in radio galaxies?
Method: spectro-photometric analysis of a sample of samples of low-luminous radio sources
Baldi Ranieri D. Ferrara, 25/05/2010
The Core Galaxies are miniature radio-galaxies (FR I).
(Balmaverde & Capetti 06 and Balmaverde,Baldi & Capetti 08).
CoreG
3CR/FRI
Baldi Ranieri D. Ferrara, 25/05/2010
The CoreG show a Core Dominance of a factor 100 larger than the classical 3C/FRI.
CoreG
3CR
Baldi Ranieri D. Ferrara, 25/05/2010
The nuclear properties of CoreG are similar to those of FRI.
CoreG show a genuine extended radio emission deficit of a factor 100.
(erg s-1) (erg s-1)
(erg
s-1)
Baldi Ranieri D. Ferrara, 25/05/2010
Our interpretation:
The prevalence of low core dominance sources in low The prevalence of low core dominance sources in low frequency fluxfrequency flux
limited samples is due to a selection bias.limited samples is due to a selection bias.
To test this scenario..
Best et al (2005) of RL AGN: crossmatching the 212000 galaxies drawn from the SDSS DR2 with the NVSS and FIRST radio surveys.Selection: [email protected] > 5 mJy
Baldi Ranieri D. Ferrara, 25/05/2010
The bulk of the population of this SDSS/NVSS AGN sample shows a large deficit of total radio emission, similar to that observed in CoreG.
3CR correlation
Seyfert
[email protected] > 5 mJy
At z=0.1 Lr = 1039 erg s-1 CoreG
0.03 < z < 0.1
(erg s-1)
(erg
s-1)
Baldi Ranieri D. Ferrara, 25/05/2010
LEG
Are there differences between SDSS/NVSS sources and 3CR/LEG?
1.Spectral classification
2.Host mass, morphology and colors
3.Black hole mass distribution
Baldi Ranieri D. Ferrara, 25/05/2010
SFG
SFG SFGLEG LEG LEG
HEGHEG
HEG
Baldi Ranieri D. Ferrara, 25/05/2010
Kew
ley
et a
l. (2
006)
Most of the radio-loud AGN of the SDSS/NVSS sample are LEG and UG: they reach the L[OIII] - Lext relation of the 3CR/LEG.
z < 0.1
Baldi Ranieri D. Ferrara, 25/05/2010
The host galaxies associated with the SDSS/NVSS sample are mostly red early-type galaxies (ETG) with no active star formation.
Baldi Ranieri D. Ferrara, 25/05/2010
Baldi Ranieri D. Ferrara, 25/05/2010
The host galaxies associated with the SDSS/NVSS sample are mostly massive ETG with large black hole masses.
The most of the SDSS/NVSS shows host properties statistically
indistinguishable from those of the 3CR/LEG hosts
All morphological classes are represented, but 80% do not show extended radio structures.
Baldi Ranieri D. Ferrara, 25/05/2010
“FIRST” radio images: FWHM = 5 arcsec
FR0
The higher fraction of UG with extended radio structures can be du to an evolution of part of the LEG population, from small radio sources of high L([OIII]), to larger size and smaller L([OIII]).
Baldi Ranieri D. Ferrara, 25/05/2010
Extended radio structures: LEG 5% UG 27%
LEG
Line emission
UG
Line emission
Baldi Ranieri D. Ferrara, 25/03/2010
There is no a clear discontinuity in either the host or nuclear properties as they span from radio-quiet and radio-loud AGN.
After a detailed analysis on a object by object, we concluded that no bona fide radio-loud AGN with LEG spectra could be found in a late-type galaxies or with log MBH < 108 Msun.
0.03 < z < 0.3 HEG:
LEG:
1. Selection bias in radio flux-limited sample causes the inclusion only of radio-galaxies with well developped extended structures. The bulk of RL AGN population is virtually unexplored -> SDSS/NVSS sample.
2. the SDSS/NVSS AGN sample is mostly composed of quiescent red, massive (10.5 < log Mgal< 12 Msun) ETG with large black hole masses (7.7 < log MBH < 9 Msun), statistically indistinguishable from hosts of low-redshift 3CR/LEG
3. No genuine radio-loud LEG in late-type galaxies and MBH < 108 Msun
4. A minority (10%) of the sample are in spiral galaxies, with small black hole masses or with HEG spectra (contamination from Seyfert and SF galaxies)
5. For HEG no separation from radio-quiet/radio-loud AGN in host properties.
Possible interpretations for low extended power:
1. Link between age and radio extended emission. Young, recurrent?
2. Influence of environment on the jets properties.
Baldi Ranieri D. Ferrara, 25/05/2010