on the spectro-photometric properties of the bulk of radio-loud agn population ranieri d. baldi 1,...

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


The CoreG show a Core Dominance of a factor 100 larger than the classical 3C/FRI.

CoreG

3CR


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)


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


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)


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


SFG

SFG SFGLEG LEG LEG

HEGHEG

HEG


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


The host galaxies associated with the SDSS/NVSS sample are mostly red early-type galaxies (ETG) with no active star formation.



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.


“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]).


Extended radio structures: LEG 5% UG 27%

LEG

Line emission

UG

Line emission


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.


on the spectro-photometric properties of the bulk of radio-loud agn population ranieri d. baldi 1,...

Documents