An Evolutionary Model of Submillimeter Galaxies Sukanya Chakrabarti NSF Fellow CFA

Merging Galaxies, Starbursts Mergers Dusty, Infrared Bright Galaxies ULIRGs – L IR > L sun Toomre & Toomre (1972): “Galactic collisions can bring deep into a galaxy a fairly sudden supply of interstellar material” Hydrodynamic simulations – Mihos & Hernquist (1996) – galactic bridges & tails, starbursts Sanders & Mirabel (1996)

Merging Galaxies, Starbursts & AGN (fast-forwarding a few years…) Chandra image of NGC 6240: (Komossa et al 03) Recent Hydrodynamical Simulations with Black Holes: Springel et al. 2005

Submillimeter Galaxies Massive galaxies, with SFR of ~ M sun /yr. Sub-mm SCUBA surveys in late 90s (Smail et al 2000, Ivison et al. 98). SMGs: F 850 > 1 mJy. Spectroscopic redshifts for higher redshift population (z~2), median F 850 ~ few mJy for z~2 population. Before Spitzer and SHARC-2 observations (Kovacs et al. 2006), mostly 850 micron, some 450 micron, radio observations, CO, and some mm imaging. X-ray observations - Alexander et al. (2005) – AGN in SMGs. Total contribution of AGN to luminosity not known. SMM J (Genzel et al 03)

How I study Dusty Galaxies (Feedback Driven Method of Study) Simulations of Galaxy Mergers Compare to observations - refine and calibrate models Radiative Transfer Calculations (RADISH): Images, SED template factory, 6 panel movies Infrared, CO (D. Narayanan), Lyman continuum, Lyman-alpha

Outline of Talk Simulations with AGN Feedback and starburst feedback for local LIRGS & ULIRGs - evolution of far-IR SEDs. Cold-Warm IRAS classification. General trends: do these two kinds of feedback affect the evolutionary history differently? Submillimeter Galaxies at z ~ 2: Photometric Properties: IRAC color-color plot What is the Role of AGN in SMGs: Infrared X-ray correlations Photo Albums of SMGs during their lifetimes Classfication & Evolutionary Scheme for SMGs Star Formation in Recent High Resolution Simulations of Quiescent Galaxies

Basics of Radiative Transfer Contribution functions & SEDs from Chakrabarti & McKee 2005 L/M and  Source of illumination does not matter for reprocessed far-IR SED What does self-consistent RT calculation mean: div F =0 -> Radiative Equilibrium. Low Intermediate High temperature Optical depth

AG N Temperature: Radiative Equilibrium Unresolved Sources Resolved Sources RADISH: Photons that emerge undergo: attenuation,scattering, reemission Chakrabarti & Whitney 2007

General Trends: Cold-Warm Transition: Telling AGN & Starbursts Apart AGN feedback: disperses gas more effectively – lower columns – more high frequency flux at peak of luminosity. Source of illumination irrelevant F(25)/F(60) increases with mass loading efficiency of starburst winds. Chakrabarti, Cox, et al. 2007a (and in Spitzer’s MIPS & Herschel’s PACS), SB winds - Cox,Chakrabarti,et al.2007 solid line: AGN feedback. Dotted:  =0.5, dashed:  =0.05,dash dotted:  =0.005 (focus on typical observed values (Martin 05,06,Rupke et al 05)

Predictions for Herschel: Cold –Warm Trend: Telling AGN & Starbursts Apart From Chakrabarti et al. 2007a

IRAC color-color plot Lacy et al. (2004) from Spitzer FLS. Dashed lines mark “AGN-demarcated region” Hot dust Bunny-ear shape clustering

IRAC color-color plots What is the clustering in the color-color plot due to? (Chakrabarti et al. 2006b) clustering AGN demarcated region

Unfolding IRAC color-color plots Clustering in color-color plots – correlated with time spent in region of color space and stars dominating in bolometric luminosity output. Clustering: time Clustering: stars Hot dust: L BH > L star

IRAC color-color plot  RAC color-color plot in rest-frame  RAC color-color plot for z=0.3 slice, bunny- ear shape. Bunny-ear shape clustering Hot dust

Life of A Sub-mm Galaxy: Time

Towards An Evolutionary Scheme for SMGs Chakrabarti et al. 2007b. SMG phase short-lived: Class I,II only, dust emission ~10 kpc

Transition from Class I -> Class II : SEDs of SMGs cold warm SED Fit to SMG data of z~1 galaxy in Pope et al Close to Class I phase, With BH ~ 40 % of L, SFR ~ 500 M sun /yr SED Fit to SMG data of z~2 galaxy in Pope et. al Close to Class II phase, with BH ~ 80 % of L, SFR ~ 300 M sun /yr

If you have any (radiative) transfer problems … Please call: RADISH

Future Directions Interfacing Simulations & Multiwavelength Observations to understand galaxy evolution: Future Space Missions: Herschel Space Observatory & JWST. High Resolution Simulations of Mergers Kazantzidis, Mayer (~few pc) Physical Models of AGN Feedback (Ciotti & Ostriker 07) High Resolution Simulations of Spiral Galaxies: how does spiral structure arise? Why does it persist? How does it affect star formation?