2012ApJ...760...11H


Query : 2012ApJ...760...11H

2012ApJ...760...11H - Astrophys. J., 760, 11 (2012/November-3)

Evidence for a clumpy, rotating gas disk in a submillimeter galaxy at z = 4.

HODGE J.A., CARILLI C.L., WALTER F., DE BLOK W.J.G., RIECHERS D., DADDI E. and LENTATI L.

Abstract (from CDS):

We present Karl G. Jansky Very Large Array observations of the CO(2-1) emission in the z = 4.05 submillimeter galaxy (SMG) GN20. These high-resolution data allow us to image the molecular gas at 1.3 kpc resolution just 1.6 Gyr after the big bang. The data reveal a clumpy, extended gas reservoir, 14 ±4 kpc in diameter, in unprecedented detail. A dynamical analysis shows that the data are consistent with a rotating disk of total dynamical mass 5.4±2.4x1011 M. We use this dynamical mass estimate to constrain the CO-to-H2 mass conversion factor (αCO), finding αCO = 1.1±0.6 M(K.km/s.pc2)–1. We identify five distinct molecular gas clumps in the disk of GN20 with masses a few percent of the total gas mass, brightness temperatures of 16-31K, and surface densities of >3200-4500x(αCO/0.8) M/pc2. Virial mass estimates indicate they could be self-gravitating, and we constrain their CO-to-H2 mass conversion factor to be <0.2-0.7 M(K.km/s.pc2)–1. A multiwavelength comparison demonstrates that the molecular gas is concentrated in a region of the galaxy that is heavily obscured in the rest-frame UV/optical. We investigate the spatially resolved gas excitation and find that the CO(6-5)/CO(2-1) ratio is constant with radius, consistent with star formation occurring over a large portion of the disk. We discuss the implications of our results in the context of different fueling scenarios for SMGs.

Abstract Copyright:

Journal keyword(s): galaxies: evolution - galaxies: formation - galaxies: high-redshift - galaxies: ISM - galaxies: star formation

Simbad objects: 9

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Number of rows : 9
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NAME GOODS-N Field reg 12 36 55.0 +62 14 15           ~ 1069 1
2 [PSD2006] GN20.2a G 12 37 08.840 +62 22 02.37     25.150     ~ 42 0
3 [PSD2006] GN20.2b smm 12 37 09.73 +62 22 02.6           ~ 17 0
4 NAME BzK 21000 rG 12 37 10.63 +62 22 34.7 23.93 25.0574     23.7554 ~ 51 0
5 NAME SMM J123711+622212 AGN 12 37 11.92 +62 22 12.1   27.1786 25.185   24.4196 ~ 189 0
6 7C 130046.50+580438.00 QSO 13 02 52.46528286 +57 48 37.6093029   20.47 19.76 20.63   ~ 86 1
7 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4170 2
8 IC 4553 SyG 15 34 57.22396 +23 30 11.6084   14.76 13.88     ~ 2872 4
9 NAME Eyelash LeG 21 35 11.60 -01 02 52.0           ~ 213 0

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2023.01.30-06:20:15

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