D. B. Sanders Institute for Astronomy, University of Hawaii Gas-Rich Mergers and the origin of nuclear starbursts and AGN The Dusty and Molecular Universe: A prelude to HERSCHEL and ALMA, Oct, 2004, Paris Starbursts and ULIRGs

IR Galaxies: SEDs, LF (vs.z) Origin & Evolution of LIGs/ULIGs ULIGs: Superstarbursts and AGN ULIGs and QSOs OUTLINE IRAS - ISO - SCUBA - MAMBO (1984) (1996) (1997) (1999) z <0.3 z < 1.5 z < 5-6 ? SIRTF+AstroF - Herschel - ALMA (2003) (2006) (2008) (2010) z = 0-10?

Two IRAS All-Sky Surveys: IRAS R evised B right G alaxy S ample (RBGS:S 60 >5.24Jy) 638 Galaxies IRAS 1-Jy ULIG Sample (1-Jy: S 60 >1.0Jy,L ir > L sun ) 118 Galaxies

Radio-to-UV SEDs of IRAS Selected Galaxies “Infrared Galaxies”  ( f ) IR / ( f ) opt > Galaxies: f ( (60  m) > 5 Jy 118 ULIGs: f ( (60  m) > 1 Jy

Galaxy Luminosity Functions L FIR high luminosity tail:   L  (z)  (1+z) 5-8  3.5  (z <0.2) ~ deg -2 slope = -1

The Hubble Deep Field (The opt/UV view) SCUBA 850  m The FIR/submm view

kindly provided by Helmut Dannerbauer

z ~ 2 – 4 f 850 ~ 1 – 10 mJy m K ~ 20 – 24 m I ~ 24 – 30 m B ~ 26 – 33 ULIGs at High Redshift

Galaxy Luminosity Functions Z=0.40 Z=0.80 Z=0.13 Z=0.045 Z ~2.4 slope= -1

The “Star Formation Rate” versus Redshift

Luminous Infrared Galaxies The Origin and Evolution of Strong Interactions/Mergers of Molecular Gas-rich Disks

IRAS RBGS Optical Images of LIGs Log L IR = Ishida, ApJL (2003 ) Log L IR =

IRAS RBGS Optical Images of LIGs Ishida, ApJL (2003 ) Log L IR =

IRAS RBGS Conclusion: In the range log(L ir /L o ) = , LIGs are in the final stages of merging, with a typical “pre-merger” time of t m < 3 x 10 8 years

IRAS RBGS Optical Images Log L IR = Ishida, ApJL (2003)

IRAS RBGS Nuclear Separation vs. L ir

IRAS RBGS Conclusion : At log(L ir /L o ) > 12.0, > 40% of ULIGs have merged and the remainder will merge within a time of t m < 10 8 years

Summary Properties of IRAS RBGS+1Jy ULIG samples Log(L IR /L sun ) = Sources are predominantly strongly interacting/merging spiral pairs  M K  Tot ~ 2 L K * M K pair ratio < 3:1 L IR pair ratio < 5:1 Pairs are predominantly late type spirals (Sb, Sc) Both components are molecular gas rich (M H2 ~ M sun )  pair separation   as  pair L IR   ( Evidence for buildup of dense nuclear gas concentrations ) ( Evidence for creation of luminous Seyfert 1 nuclei) ( Evidence for S + S  E )

L CO N=53 L HCN

L IR /L HCN L IR /L CO L HCN L CO

Gao et al. Mirabel et al. Hibbard et al. Ponman et al. Log (L IR /L sun ) = Int. Class = 3

UGC = Mrk 231 Log (L IR /L sun ) = Int. Class = 4 Sanders et al. Hutchings & Neff Scoville et al. Surace et al

Summary Nuclear Molecular Gas r < 700 pc General Results for ULIGs M nuc /M tot = 40 – 100 % M nuc = 1 – 3 x M sun   (H 2 )  ~ 0.65 – 2 x M sun  n (H 2 )  spherical ~ 130 – 400 cm -3 => ff nuc ~ 1 ( for a population of W3-like GMCs )  N (H 2 )  spherical ~ – 23.7 cm -2 OVRO Interferometer Bryant, Scoville et al

Summary Optical Spectral Classification of LIGs+ULIGs Veilleux, Kim & Sanders (1998)KPNO 4m + UH 2.2m

1-D surface brightness radial profiles

Summary Host Properties of 1-Jy Sample of ULIGs Log(L IR /L sun ) > 12.0 redshift range: –  M K  Tot ~ 2.7 L K *  M R  Tot ~ 2.5 L R * ~ 1/3 are E (r 1/4 -law r ~ 1.5 – 6.0 kpc) ~ 1/3 are E/Sp ~ 1/3 are “amorphous/chaotic”

Beyond the IRAS RBGS Sample … Question: What happens Next ?

A Plausible Scenario … LIG ULIG QSO

Evolution of Fine Structure in a “post-merger” simulation Barnes (2002)

Evolution of the Luminosity Profile for a “Post-Merger” Remnant Barnes (2002)  R = 27.5 mag arcsec -2 (kpc)

Near-IR Imaging of PGQSOs with Gemini-North Hopuka’a AO System (Olivier Guyon 2002) PG x40 kpc “Raw Image” (resolution ~0.12 arcsec) PSF-subtracted image ~24 mag H arcsec -2 (3  )

NIR-AO Imaging of a Complete Sample of 38 PGQSOs Olivier Guyon, PhD Thesis, 2002 Raw (H-band) -psf - Gemini-N 8m

NIR-AO Imaging of a Complete Sample of 38 PGQSOs Olivier Guyon, PhD Thesis, 2002 Raw (H-band) -psf - Mean Radio-to-Xray SED of PGQSOs

Warped Disk Model Sanders, Phinney et al. (1989)

PGQSOs typically have dominant spheroids + a moderate disk component (central bars, mini-spirals, …) PGQSO hosts typically have faint tidal debris

“SFR + MBH” versus Redshift

Good evidence for S + S -> E merger sequence for ULIGs Good evidence for creation of luminous Seyfert 1 nuclei in ULIGs Confirmation of strong evolution with z in the ULIG population ISOPHOT Deep Field sources consistent with LIG/ULIGs (z ≈ ) ?? SCUBA Deep Field sources consistent with LIG/ULIGs (z ≈2 - 4)?? Summary [“SFR” vs. z ] opt+UV  [“SFR” vs. z ] IRAS+ISO+SCUBA High-z ULIGs may represent epoch of spheroid / MBH formation