Query : 2018A&A...619A..15G

2018A&A...619A..15G - Astronomy and Astrophysics, volume 619A, 15-15 (2018/11-1)

Physics of a clumpy lensed galaxy at z=1.6.


Abstract (from CDS):

Observations have shown that massive star-forming clumps are present in the internal structure of high-redshift galaxies. One way to study these clumps in detail with a higher spatial resolution is by exploiting the power of strong gravitational lensing which stretches images on the sky. In this work, we present an analysis of the clumpy galaxy A68-HLS115 at z=1.5858, located behind the cluster Abell 68, but strongly lensed by a cluster galaxy member. Resolved observations with SINFONI/VLT in the near-infrared (NIR) show Hα, Hβ, [NII], and [OIII] emission lines. Combined with images covering the B band to the far-infrared (FIR) and CO(2-1) observations, this makes this galaxy one of the only sources for which such multi-band observations are available and for which it is possible to study the properties of resolved star-forming clumps and to perform a detailed analysis of the integrated properties, kinematics, and metallicity. We obtain a stability of υrot0=2.73 by modeling the kinematics, which means that the galaxy is dominated by rotation, but this ratio also indicates that the disk is marginally stable. We find a high intrinsic velocity dispersion of 80±10km/s that could be explained by the high gas fraction of fgas=0.75±0.15 observed in this galaxy. This high fgas and the observed sSFR of 3.12Gyr–1 suggest that the disk turbulence and instabilities are mostly regulated by incoming gas (available gas reservoir for star formation). The direct measure of the Toomre stability criterion of Qcrit=0.70 could also indicate the presence of a quasi-stable thick disk. Finally, we identify three clumps in the Hα map which have similar velocity dispersions, metallicities, and seem to be embedded in the rotating disk. These three clumps contribute together to ∼40% on the SFR of the galaxy and show a star formation rate density about ∼100 times higher than HII regions in the local Universe.

Abstract Copyright: © ESO 2018

Journal keyword(s): galaxies: high-redshift - galaxies: kinematics and dynamics

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
1 ACO 68 ClG 00 37 06.2 +09 09 33           ~ 168 0
2 [SZS2014] A68/HLS115 LeG 00 37 09.500 +09 09 03.97           ~ 5 0
3 NAME Hubble Ultra Deep Field reg 03 32 39.0 -27 47 29           ~ 1393 0

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