Astro 641 AGN Mapping the Evolution of AGN More material: This lecture!

3C Radio Survey Third (revised) Cambridge Catalogue of radio sources using extended emission at 178 MHz. Low selection frequency: steep spectra Survey of all sources north of -5 deg with f R >9 Jy. 328 sources. Complete sample: Laing, Riley and Longair (1983). 96% complete to 10 Jy.

V/V max Test

Flux-limited sample --> at small distances larger luminosity range. Solution: compute for each source the max. redshift at which it would still be included in a complete survey --> maximum volume V max. V/V max is a measure of the source position within the observable volume. V/Vmax uniform in [0,1] range. =0.5.

V/V max Test Laing, Riley & Longair (1983)

IRAS de Grijp et al. (1987)

Spitzer Lacy et al. (2004)

Stern Diagram Stern et al. (2005)

Power-law AGN Donley et al. (2008) Selection: IRAC photometry is well-fit by a line of slope  <-0.5

Why does it work? Hickox et al. (2007)

Fraction of Recovered Sources Stern et al. (2005)

X-ray Selected Sources Cardamone et al. (2008)

X-ray Selected Sources Cardamone et al. (2008)

X-ray Selected Sources Eckart et al. (2010)

X-ray Selected Sources Eckart et al. (2010)

Summary

24  m Selection Brand et al. (2006)

24  m Selection Brand et al. (2006)

AGN Fraction Treister et al. (2006)

AGN Contribution to IR Background Treister et al. (2006)

Fiore et al Finding Heavily-Obscured AGN Mid-IR X-ray Stacking F 24 /F R >1000 F 24 /F R <200 4  detection in X-ray stack. Hard spectral shape, harder than X- ray detected sources.  Good CT AGN candidates. Similar results found by Daddi et al. (2007)

Rest-Frame Stacking Good fit with either NH  cm -2 or combination of CT AGN with star-forming galaxies. Consistent results with observed-frame stacking. Treister et al. ApJ 2009c

X-Ray to Mid-IR Ratio ~100x lower ratio for X-ray undetected sources. Explained by N H ~5x10 24 to cm -2 Treister et al. ApJ 2009c Both X-rays and 12µm good tracers of AGN activity.

X-Ray to Mid-IR Ratio Ratio for sources with L 12µm >10 43 erg/s (~80% of the sources) ~2-3x higher than star-forming galaxies Treister et al. ApJ 2009c

Near to Mid-IR Colors - Distributions significantly different - X-ray detected sources much bluer - Average f 8 /f 24 =0.2 for X-ray sources and 0.04 for X-ray undetected sample BluerRedder Well explained by different viewing angle (30 o vs 90 o ) in the same torus model Can it be star-formation versus AGN? Treister et al. ApJ 2009c

Near to Mid-IR Colors Armus et al ULIRG, LINER ULIRG, Sey2

IRAC Colors [5.8]-[8] (Vega) [3.6]-[4.5] (Vega) z=0-1 z>1 AGN Faint 8 µm Treister et al. ApJ 2009c

IRAC Colors log (f 5.8 /f 3.6 ) log (f 8 /f 4.5 ) Faint 8µm Treister et al. ApJ 2009c

Mid-IR/Radio Selection Donley et al. (2005)

Mid-IR/Radio Selection Park et al. (2008) Martinez-Sansigre et al. (2005)

Mid-IR/Radio Selection Barger et al. (2007)

Putting it all together Hickox et al. (2009)

AGN Fraction Donley et al. (2008)

q vs IR Lum Kartaltepe et al. (2010)

Stern Diagram Kartaltepe et al. (2010)

Mid-IR Excess Kartaltepe et al. (2010)

Redshift and L IR Distributions Kartaltepe et al. (2010)

AGN Fraction Kartaltepe et al. (2010)