TY - JOUR
T1 - Towards a resolved Kennicutt-Schmidt law at high redshift
AU - Freundlich, J.
AU - Combes, F.
AU - Tacconi, L. J.
AU - Cooper, M. C.
AU - Genzel, R.
AU - Neri, R.
AU - Bolatto, A.
AU - Bournaud, F.
AU - Burkert, A.
AU - Cox, P.
AU - Davis, M.
AU - Förster Schreiber, N. M.
AU - Garcia-Burillo, S.
AU - Gracia-Carpio, J.
AU - Lutz, D.
AU - Naab, T.
AU - Newman, S.
AU - Sternberg, A.
AU - Weiner, B.
N1 - Funding Information:
J. Freundlich acknowledges support by the École Normale supérieure (ENS, Paris), and is thankful to Philippe Salomé for numerous technical tips and Martin Stringer for his proofreading and suggestions. The authors wish to thank the anonymous referee, whose comments have led to significant improvements in this paper. This work is based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). This work also makes use of data from AEGIS, a multiwavelength sky survey conducted with the Chandra, GALEX, Hubble, Keck, CFHT, MMT, Subaru, Palomar, Spitzer, VLA, and other telescopes and supported in part by the NSF, NASA, and the STFC.
PY - 2013
Y1 - 2013
N2 - Massive galaxies in the distant Universe form stars at much higher rates than today. Although direct resolution of the star forming regions of these galaxies is still a challenge, recent molecular gas observations at the IRAM Plateau de Bure interferometer enable us to study the star formation efficiency on subgalactic scales around redshift z = 1.2. We present a method for obtaining the gas and star formation rate (SFR) surface densities of ensembles of clumps composing galaxies at this redshift, even though the corresponding scales are not resolved. This method is based on identifying these structures in position-velocity diagrams corresponding to slices within the galaxies. We use unique IRAM observations of the CO(3-2) rotational line and DEEP2 spectra of four massive star forming distant galaxies - EGS13003805, EGS13004291, EGS12007881, and EGS13019128 in the AEGIS terminology - to determine the gas and SFR surface densities of the identifiable ensembles of clumps that constitute them. The integrated CO line luminosity is assumed to be directly proportional to the total gas mass, and the SFR is deduced from the [OII] line. We identify the ensembles of clumps with the angular resolution available in both CO and [OII] spectroscopy; i.e., 1-1.5′′. SFR and gas surface densities are averaged in areas of this size, which is also the thickness of the DEEP2 slits and of the extracted IRAM slices, and we derive a spatially resolved Kennicutt-Schmidt (KS) relation on a scale of ~8 kpc. The data generally indicates an average depletion time of 1.9 Gyr, but with significant variations from point to point within the galaxies.
AB - Massive galaxies in the distant Universe form stars at much higher rates than today. Although direct resolution of the star forming regions of these galaxies is still a challenge, recent molecular gas observations at the IRAM Plateau de Bure interferometer enable us to study the star formation efficiency on subgalactic scales around redshift z = 1.2. We present a method for obtaining the gas and star formation rate (SFR) surface densities of ensembles of clumps composing galaxies at this redshift, even though the corresponding scales are not resolved. This method is based on identifying these structures in position-velocity diagrams corresponding to slices within the galaxies. We use unique IRAM observations of the CO(3-2) rotational line and DEEP2 spectra of four massive star forming distant galaxies - EGS13003805, EGS13004291, EGS12007881, and EGS13019128 in the AEGIS terminology - to determine the gas and SFR surface densities of the identifiable ensembles of clumps that constitute them. The integrated CO line luminosity is assumed to be directly proportional to the total gas mass, and the SFR is deduced from the [OII] line. We identify the ensembles of clumps with the angular resolution available in both CO and [OII] spectroscopy; i.e., 1-1.5′′. SFR and gas surface densities are averaged in areas of this size, which is also the thickness of the DEEP2 slits and of the extracted IRAM slices, and we derive a spatially resolved Kennicutt-Schmidt (KS) relation on a scale of ~8 kpc. The data generally indicates an average depletion time of 1.9 Gyr, but with significant variations from point to point within the galaxies.
KW - Galaxies: ISM
KW - Galaxies: evolution
KW - Galaxies: high-redshift
KW - Galaxies: starburst
KW - Galaxies: structure
KW - Stars: formation
UR - http://www.scopus.com/inward/record.url?scp=84878291630&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201220981
DO - 10.1051/0004-6361/201220981
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AN - SCOPUS:84878291630
SN - 0004-6361
VL - 553
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A130
ER -