The merger fraction of radio loud (and radio quiet) AGN clues on the AGN triggering mechanism

Transcription

1 The merger fraction of radio loud (and radio quiet) AGN clues on the AGN triggering mechanism Marco Chiaberge Space Telescope Science Ins4tute Johns Hopkins University

2 RQ RL the RL/RQ dichotomy Kellerman et al PG QSO Bimodal distribution? White et al. 2000, Izevic et al. 2004, Cirasuolo et al 2007, Balokovic et al 2012 RL/RQ separation R = F 5GHz / F B = 10 R > 10 is a good defini/on of radio loudness for QSOs At low L bol the threshold shifts towards higher values R~100 Chiaberge et al. 06, Sikora et al 2007

3 WHY ARE RADIO- LOUD AGN IMPORTANT? RADIO LOUD AGN are associated with the most massive BH and ellip/cals, and are o^en in BCGs RADIO GALAXIES are o^en used as beacons for clusters of galaxies FEEDBACK: HOW DOES AGN ACTIVITY AFFECT GALAXY FORMATION AND EVOLUTION? HOW DO OUTFLOWS AND JETS AFFECT THE INTRA- CLUSTER MEDIUM? Do all galaxies go through an AGN phase? BH/AGN PHYSICS: How do the most massive black holes grow? How does mazer lose angular momentum and ul/mately feeds the central BH? What powers rela/vis/c jets? Are mergers playing a role?

4 DO MERGERS PLAY A ROLE IN TRIGGERING AGN ACTIVITY? WHAT TRIGGERS A RADIO- LOUD AGN? THE ENVIRONMENT OF POWERFUL high- z RADIO- LOUD AGN

5 MERGERS and AGN activity: still debated Some evidence that some AGNs are more common in close (interacting) pairs e.g. Silverman et al. 2011, Satyapal et al. 2014, Ellison et al (and this conference) Merger fraction in X-ray AGN increases with N H (~20%) Kocevski et al 2015 Distributions of asymmetry and concentration indices in GOODS show no connection between recent mergers and X-ray selected AGNs Grogin et al 2005, Schawinsky et al Powerful reddened QSOs at z~2 L bol ~ erg s -1 are mergers Urrutia et al. 2008, Treister et al. 2011, Glikman et al Powerful QSO are NOT mergers Mechtley et al No dependence of AGN merger fraction on luminosity. Less than 40% of the highest luminosity AGNs may be triggered by mergers (CANDELS) Villforth et al ULIRGs are mergers Veilleux et al (Most) low z Radio Galaxies are mergers Heckman 1986, Colina & de Juan 1995, Ramos Almeida et al. 2012, Tadhunter 2016 (review)

6 3CR HST SNAPSHOT survey Cycle Radio galaxies (Type 2) +10 QSOs (Type 1) 1 < z < 2.5 HST WFC3 UVIS F606W + IR F140W L bol ~ erg s -1 PI M. Chiaberge W.B. Sparks (STScI) G. Miley (Leiden) G. Tremblay (Yale) A. Capetti (INAF-OATO) D. Macchetto (STScI) S. Baum (U.Manitoba) C. O Dea (U. Manitoba) E. Perlman (FIT) A. Quillen (UofR) B. Hilbert (STScI) JP Kotyla (STScI) C. Stanghellini (INAF-IRA) C. Norman (JHU/STScI) J. Lotz (STScI) R. Gilli (INAF-OABo) Hilbert, Chiab et al. (2016) Adapted form McLure et al 04, Willott et al

7 POWERFUL RADIO GALAXIES AT z>1 3CR images with HST WFC3/IR F140W Chiaberge, Gilli, Lotz & Norman (2015)

8 WHAT IS THE ROLE OF MERGERS? Radio loud and radio quiet Type 2 AGNs at 1< z< 2.5 observed with HST- WFC3/IR 11 3C High Luminosity radio galaxies 9 High Luminosity Type 2 RQAGN L IR ~ erg s -1 Podigachoski et al. 2015, Cardamone et al Low luminosity radio galaxies 26 Low luminosity Type 2 RQAGN L 2-10keV ~ erg s -1 Xue et al. 2011, Bonzini et al Bright Galaxies (matched with the 3CR hosts) 19 < m F140W < Faint Galaxies (matched with the radio quiet samples) 22 < m Ks < High-mass galaxies (matched with the 3CR hosts) 1x10 11 < M < 5x10 11 M Sun e.g. Seymour et al 2007 Data from ECDFS Lehmer et al Ms CDFS Xue et al. 2011, CANDELS Grogin et al. 11 Koekemoer et al. 11 3D-HST Brammer et al. 12

9 3C 297 Radio galaxy at z = 1.4 HST WFC3/ UVIS F606W WFC3/IR F140W

10 3C 210 Radio galaxy at z = HST WFC3/ UVIS F606W WFC3/IR F140W

11 RESULTS: merger fractions 95% credible interval 3CR HLRGs 94% [78-100%] High-z LLRGs 82% [57-99%] Low Power TY2 AGN 39% [22-57%] High Power TY2 AGN 36% [11-64%] Non-active Bright Galaxies 27% [15-40%] Non-active Faint Galaxies 20% [10-33%] RADIO LOUD vs RADIO QUIET AGNs and RL vs non active galaxies are NOT the same High statistical significance (p<0.01) High-z LLRGs are 4 dex less luminous than 3C s NO DEPENDENCE ON AGN LUMINOSITY Caveat: the AGN samples are SMALL!

12 ANY REDSHIFT DEPENDENCE? HST WFPC2 F850LP Cycle 10 McLure et al (2004) MERGER FRACTIONS IN THE RANGE 65%-74% STATISTICALLY INDISTINGUISHIBLE FROM THE z>1 samples In agreement with Ramos Almeida 2012 PI C. WIllott

13 MERGER FRACTIONS vs REDSHIFT Bayesian 95% credible intervals 3CR Hz3C + HzLPRG 3CR 6CE 7CRS TOOT RADIO LOUD RQTY2AGN Galaxies

14 MERGERS Radio-loud AGN CONJECTURE: M BH > 10 8 M Chiaberge & Marconi 2011 Laor et al Dunlop et al Best et al Chiaberge et al 2006 Calderone et al Bagchi et al Singh et al Mao et al BH SPIN jets are powered by spinning BHs L EM λ 2 B 2 M 2 BH Blanford & Znajek 1977 Tchekhovskoy et al Ghisellini et al Major galaxy mergers AND major BH-BH mergers In some cases, BH-BH mergers lead to BH spin-up (e.g. Schnittman 2013) Wilson & Colbert 1995 Accretion is disfavored because low-z RLAGNs are in gas-poor galaxies (dry mergers)

15 THE ENVIRONMENT OF z>1 POWERFUL Ty1 and Ty2 RADIO-LOUD AGNs Questions: Kotyla, Chiab et al. (2016) What is the fraction of RLAGN in clusters/groups? Galametz et al. 2012, Wylezalek et al. 2013, Chiaberge et al. 2010, Castignani et al Do radio galaxies and quasars live in different Mpc-scale environments? Can we use RLAGNs at high-z to study galaxy and cluster evolution? At what redshift does the red-sequence break down? Faber et al. (2007)

16 The Mpc-scale environment of high-z radio-loud AGN Over density Over density Kotyla, Chiab, et al. 2016

17 The Environment of z>1 powerful radio-loud AGN On average powerful RLAGN live in over-dense environments No difference between QSO (Ty1) and RG (Ty2) Kotyla,et al ~50% of the targets are in over-dense regions >3σ The ETGs evolve from a blue sequence to the red sequence z< <z<1.75 z>1.75 z=1.0 z=2.5

18 SUMMARY Mergers are strictly connected with Radio Galaxies RQAGN show a merger fraction that is similar to that of non-active galaxies Radio galaxies are ~3x more likely to be in a merger than Radio Quiet AGN or non-agn (but that is from ~30% to ~100%!!!) No dependence on either redshift or luminosity (but the details of the merger may be different) This fits in a scenario where RL AGNs are linked to major mergers of galaxies with >10 8 M sun black holes and the BH is spun-up by the BH-BH merger ~50% of z>1 3C radio galaxies and QSOs inhabit clusters/groups There is evidence for the build-up of the red sequence between z~2.5 and z~1.5