ULTRALUMINOUS INFRARED GALAXIES: 2D KINEMATICS AND STAR FORMATION L. COLINA, IEM/CSIC S. ARRIBAS,...
-
date post
20-Dec-2015 -
Category
Documents
-
view
222 -
download
0
Transcript of ULTRALUMINOUS INFRARED GALAXIES: 2D KINEMATICS AND STAR FORMATION L. COLINA, IEM/CSIC S. ARRIBAS,...
ULTRALUMINOUS INFRARED GALAXIES: 2D KINEMATICS AND STAR FORMATION
L. COLINA, IEM/CSIC
S. ARRIBAS, STSCI & CSIC
D. CLEMENTS, IMPERIAL COLLEGEA. MONREAL, IACM. 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 PHASEZ < 0.2 11.8 < log(LIR/L) < 12.6 HII - Sy1 EARLY/LATE
INTEGRAL on WHT
3 fiber bundles:
2.7033.6x29.4SB3
0.9016.0x12.3SB2
0.457.80x6.40SB1
Ø (”)FoV (”x”)Mode
Arribas et al. 1998
INTEGRAL FIELD SPECTROSCOPY OF ULIRGS
ARP 220: INTEGRAL FIELD SPECTROSCOPY (I)*
* Colina, Arribas & Clements, 2004, ApJ 602
28 X 15 Kpc
SB3 BUNDLE
15000 s
6000 s 18000 s
ARP 220: INTEGRAL FIELD SPECTROSCOPY (II)
Log F(H) > -17 erg cm-2 s-1 arcec-2
350 spectra4500 - 7500 A
ARP 220: ORIGIN OF EXTENDED IONIZED GAS*
3 6.2 2.7 10.49NGC 3079
1.3 1.5 0.37 10.46NGC 253
24 0.3 0.16 12.16Arp 220 Lobes
7 0.6 0.14 12.16Arp 220 Plumes
Extent (kpc)
LX/LIR
(xE-5)
LH /LIR
(xE-5)
log LIR
(L)
Galaxy
* Colina, Arribas, Clements 2004, ApJ 602
M82 10.52 16 2.6 2.4
Distance (Mpc)
77.6
77.6
3.0
3.0
16
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)
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 V2 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 Re
: Central velocity dispersionRe: 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 SPECTROSCOPYComplex 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
Av (C)= 5.6 magAv (D)= 2.2 mag
IMPLICATIONS FOR HIGH-Z GALAXIES (II)
García-Marín, Colina & Arribas, see poster
HST F814WNIRCam Z=2.5
INTEGRAL H
NIRSpecIFU H
SFR(1)/SFR(2)= 2 m(1)/m(2)=0.25
1
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 Mdyn
H central velocity dispersions are a more reliable tracer of the Mdyn, 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.