ULTRALUMINOUS INFRARED GALAXIES: 2D KINEMATICS AND STAR FORMATION L. COLINA, IEM/CSIC S. ARRIBAS, STSCI & CSIC D. CLEMENTS, IMPERIAL COLLEGE A. MONREAL, IAC M. GARCIA-MARIN, IEM/CSIC

SAMPLE OF LOW-Z ULIRGs AND INSTRUMENTATION ARP 220: STRUCTURE OF THE EXTENDED WARM IONIZED GAS 2D KINEMATICAL PROPERTIES OF ULIRGS DYNAMICAL MASS TRACERS IMPLICATIONS FOR HIGH-Z GALAXIES: SFR AND MASS CONCLUSIONS OUTLINE

SAMPLE OF LOW-Z ULIRGS REDSHIFT LUMINOSITY ACTIVITY MERGING PHASE Z < < log(L IR /L  ) < 12.6 HII - Sy1 EARLY/LATE

INTEGRAL on WHT 3 fiber bundles: x29.4SB x12.3SB x6.40SB1 Ø (”)FoV (”x”)Mode Arribas et al INTEGRAL FIELD SPECTROSCOPY OF ULIRGS

ARP 220: INTEGRAL FIELD SPECTROSCOPY (I)* * Colina, Arribas & Clements, 2004, ApJ X 15 Kpc SB3 BUNDLE s 6000 s18000 s

ARP 220: INTEGRAL FIELD SPECTROSCOPY (II) Log F(H  ) > -17 erg cm -2 s -1 arcec spectra A

ARP 220: HST vs IFS STELLAR STRUCTURE WFPC2 F814W INTEGRAL SB3 *

ARP 220: 2D IONIZED GAS STRUCTURE W LOBE E LOBE NW PLUME SE PLUME

ARP 220: ORIGIN OF EXTENDED IONIZED GAS* NGC NGC Arp 220 Lobes Arp 220 Plumes Extent (kpc) L X /L IR (xE-5) L H  /L IR (xE-5) log L IR (L  ) Galaxy * Colina, Arribas, Clements 2004, ApJ 602 M Distance (Mpc) STARBURST-INDUCED SUPERWINDS OR MERGER-INDUCED SHOCKS

ARP 220: ORIGIN OF EXTENDED IONIZED GAS McDowell et al. 2003, ApJ 591 MERGER-INDUCED STRUCTURES? SIMULATION (S. LAMB) - Gas-rich galaxies - Comparable-mass - Low impact velocity - Face-on collision

ARP 220: VELOCITY vs STELLAR AND GAS STRUCTURES STELLAR STRUCTURE GAS STRUCTURE STELLAR STRUCTURE - Peak-to-peak V of 600 km/s - Vel. Deviations of  300 km/s - Vel gradients of 50 km/s/kpc - Associated with the stellar envelope - Average velocities of E and W lobes: +8 and -79 km/s - Not dominated by central, starburst-driven wind - Average velocities of E and W lobes consistent with merger simulations (to first order)

2D KINEMATICAL PROPERTIES OF ULIRGS (I) HST F160W CONT. H  VELOCITY DISP. VELOCITY FIELD

2D KINEMATICAL PROPERTIES OF ULIRGS (II) HST F160W CONT. H  VELOCITY DISP. VELOCITY FIELD

 Velocity field on scales of few to several kpc does not correspond in general to that of an ordered, rotating system  Peak-to-peak velocity amplitudes of up to 600 km/s are detected in tidally induced structures: tails and extranuclear star-forming regions  The peak of the velocity dispersion in 60% of the ULIRGs studied does not coincide in position with the stellar nucleus  Velocity dispersions associated with extranuclear, diffuse ionized gas are large: 150 to 250 km/s  Velocity dispersion associated with the less massive, secondary nucleus in pairs is not distinguishable from that of the extended, diffuse gas  Extended ionized gas velocities on scales of few to several kpc are not wind-related but merger-induced 2D KINEMATICS OF ULIRGS: SUMMARY

MASS TRACER: CENTRAL VELOCITY AMPLITUDE  : cold gas  : stars IF ROTATION: MASS  V 2 R HOWEVER VELOCITY AMPLITUDE DOES NOT TRACE ROTATION, IN GENERAL VELOCITY AMPLITUDE IS NOT A RELIABLE TRACER OF DYNAMICAL MASS

MASS TRACER: CENTRAL VELOCITY DISPERSION  : stars  : cold gas MASS   2 R e  : Central velocity dispersion R e : Effective radius VELOCITY DISPERSION IS A RELIABLE TRACER OF DYNAMICAL MASS ULIRG MASSES 0.1m * < m < 1.1m * m= 0.4  0.3 m * m * = 1.4E+11 M 

IMPLICATIONS FOR HIGH-Z GALAXIES: SFR and MASS LIRGS and ULIRGs carry a large fraction oof SF at z> 1 SPITZER and HERSCHEL most likely to detect LIRGs at high-z KEY PARAMETERS  SFR AND DYNAMICAL MASS  H  line Strong differential extinction effects Decoupled ionized & stellar structures INTEGRAL FIELD SPECTROSCOPY Complex 2D velocity field H  line shifts into the near and mir-IR (1 to 10 micron) for z> 1 near-IR multi-slit spectrographs NOT GOOD ENOUGH  MISLEADING DERIVATIONS OF SFRs AND MASSES IN HIGH-Z LUMINOUS DUST-ENSHROUDED STARBURST

IMPLICCATIONS FOR HIGH-Z GALAXIES (I) García-Marín, Colina & Arribas, see poster A v (C)= 5.6 mag A v (D)= 2.2 mag

IMPLICATIONS FOR HIGH-Z GALAXIES (II) García-Marín, Colina & Arribas, see poster HST F814W NIRCam Z=2.5 INTEGRAL H  NIRSpec IFU H  SFR(1)/SFR(2)= 2 m(1)/m(2)=

IMPLICATIONS FOR HIGH-Z GALAXIES: SUMMARY IF most high-z galaxies are merging systems such as low-z ULIRGs THEN  H  velocity amplitudes should not be used in general to estimate M dyn  H  central velocity dispersions are a more reliable tracer of the M dyn, provided the true nucleus is known from near-IR imaging  H  -based star formation rates can be underestimated, factors 2 or 3 in some systems, even if corrected by strong differential extinction effects  Long-slit spectroscopy could give misleading results. IFS desirable.