The Starburst-AGN Connection Among COSMOS (U)LIRGs Jeyhan Kartaltepe - NOAO COSMOS Meeting – IfA, Honolulu, HI 2010 June 8 D. Sanders, V. Smolcic, L. Kewley, M. Salvato, P. Capak, E. Le Floc’h, H. Aussel, D. Frayer et al.

COSMOS 70 mm Sample Paper I Paper II Next… SEDs  Kartaltepe et al. 2010, ApJ, 709, 572 Paper II Morphology  re-submitted, should hear back any day Next… The Starburst-AGN Connection Among COSMOS (U)LIRGs Focus on optical spectroscopy out to z~1

The Starburst-AGN Connection Starburst/AGN activity are directly linked Together may regulate black hole/bulge growth in galaxies Luminous infrared galaxies have high luminosities due to dust enshrouded SF/AGN activity Each contribute to the bolometric luminosity How can we separate the two? What can we do with existing optical spectroscopy?

COSMOS 70 mm Sample 1503 sources with 0 < z < 3 Spectroscopy for ~40% zCOSMOS, DEIMOS, etc. Eventual goal: correlate activity with luminosity/morphology HyLIRGs ULIRGs log (LIR) LIRGs Redshift (z)

AGN Selection Methods X-ray luminosity Radio power SED shape (i.e., Power-law) IRAC colors Infrared to optical ratio (e.g., Fiore et al. 2008, Dey et al. 2008) Spectroscopic diagnostics

Fraction of Sources with AGN Signatures 100% for HyLIRGs >70% for ULIRGs AGN Fraction 5% at low LIR log (LIR)

At low redshift…. At low redshift, can classify 135 galaxies using standard line diagnostics 0 < z < 0.5 (where Ha still observable, 18% of sample at these redshifts) log(LIR) = 8.8 – 11.7, <log(LIR)> = 10.6

At low redshift…. 8 (6%) classified as AGN 34 (25%) classified as composite 93 (69%) classified as star forming  Many more sources identified as AGN through spectroscopy than other selection methods

Use color as a proxy for [NII]/Ha? AGN 380 sources (0 < z < 1) 8 sources selected 2 X-ray detected Another 2 (z<0.5) have Ha Both are Seyferts on all 3 low-z diagnostics DEEP2: e.g., Montero-Dorta et al. 2009

Color Correlation between rest-frame color and galaxy’s position on BPT diagram for radio selected sources P1 ‘color’ (derived from modified Stromgren system for SDSS galaxies) correlates with metallicity and stellar population, P2 with dust P1 > 0.15  AGN selection Appears to work well at low z, results at high z are untested Is there redshift evolution? Can composites be separated? Smolcic et al. 2006, 2008

[OII] EW vs. Hb EW 218 Sources (0 < z < 1) 22 sources selected None are AGN by other methods 8 overlap with low-z sample 4 SF on all 3 diagrams Other 4 are either Seyferts, LINERS, or composites on 2 out of 3 DEEP2: e.g.,Yan et al. 2006; Willmer et al. 2006; Montero-Dorta et al. 2009

Future Work Incorporate new spectra Further tests DEIMOS, 20k sample, etc. Further tests Evolution of P1 with redshift Lamareille et al. (2004, 2010) diagnostics X-ray stacking Compare diagnostics with SDSS in the local universe z > 1 ? NIR Spectroscopy (FMOS, MOSFIRE, MOIRCS, FLAMINGOS2, etc.)