%0 Generic %1 scoville2015masses %A Scoville, N. %A Sheth, K. %A Aussel, H. %A Bout, P. Vanden %A Capak, P. %A Bongiorno, A. %A Casey, C. M. %A Murchikova, L. %A Koda, J. %A Pope, A. %A Toft, S. %A Ivison, R. %A Sanders, D. %A Manohar, S. %A Lee, N. %D 2015 %K galaxy gas high-z molecular sfr %T ISM Masses and Star Formation at z = 1 to 6 ALMA Observations of Dust Continuum in 180 Galaxies in COSMOS %U http://arxiv.org/abs/1505.02159 %X ALMA Cycle 2 observations of the long wavelength dust emission in 180 star-forming (SF) galaxies are used to investigate the evolution of ISM masses at z = 1 to 6.4. The ISM masses exhibit strong increases from z = 0 to $\rm <z>$ = 1.15 and further to $<z>$ = 2.2 and 4.8, particularly amongst galaxies above the SF galaxy main sequence (MS). The galaxies with highest SFRs at $<z>$ = 2.2 and 4.8 have gas masses 100 times that of the Milky Way and gas mass fractions reaching 50 to 80\%, i.e. gas masses 1 - 4$\times$ their stellar masses. For the full sample of galaxies, we find a single, very simple SF law: $SFR M_ISM^0.9$, i.e. a `linear' dependence on the ISM mass -- on and above the MS. Thus, the galaxies above the MS are converting their larger ISM masses into stars on a timescale similar to those on the MS. At z $> 1$, the entire population of star-forming galaxies has $\sim$5 - 10$\times$ shorter gas depletion times ($\sim0.2$ Gyr) than galaxies at low redshift. These shorter depletion times are due to a different, dominant mode of SF in the early universe -- dynamically driven by compressive, high dispersion gas motions and/or galaxy interactions. The dispersive gas motions are a natural consequence of the extraordinarily high gas accretion rates which must occur to maintain the prodigious SF.

@misc{scoville2015masses, abstract = {ALMA Cycle 2 observations of the long wavelength dust emission in 180 star-forming (SF) galaxies are used to investigate the evolution of ISM masses at z = 1 to 6.4. The ISM masses exhibit strong increases from z = 0 to $\rm <z>$ = 1.15 and further to $\rm <z>$ = 2.2 and 4.8, particularly amongst galaxies above the SF galaxy main sequence (MS). The galaxies with highest SFRs at $\rm <z>$ = 2.2 and 4.8 have gas masses 100 times that of the Milky Way and gas mass fractions reaching 50 to 80\%, i.e. gas masses 1 - 4$\times$ their stellar masses. For the full sample of galaxies, we find a single, very simple SF law: $\rm SFR \propto M_{\rm ISM}^{0.9}$, i.e. a `linear' dependence on the ISM mass -- on and above the MS. Thus, the galaxies above the MS are converting their larger ISM masses into stars on a timescale similar to those on the MS. At z $> 1$, the entire population of star-forming galaxies has $\sim$5 - 10$\times$ shorter gas depletion times ($\sim0.2$ Gyr) than galaxies at low redshift. These {\bf shorter depletion times are due to a different, dominant mode of SF in the early universe} -- dynamically driven by compressive, high dispersion gas motions and/or galaxy interactions. The dispersive gas motions are a natural consequence of the extraordinarily high gas accretion rates which must occur to maintain the prodigious SF.}, added-at = {2015-05-12T09:57:30.000+0200}, author = {Scoville, N. and Sheth, K. and Aussel, H. and Bout, P. Vanden and Capak, P. and Bongiorno, A. and Casey, C. M. and Murchikova, L. and Koda, J. and Pope, A. and Toft, S. and Ivison, R. and Sanders, D. and Manohar, S. and Lee, N.}, biburl = {https://www.bibsonomy.org/bibtex/23551bed881e290a1bed43a27de9e0177/miki}, description = {[1505.02159] ISM Masses and Star Formation at z = 1 to 6 ALMA Observations of Dust Continuum in 180 Galaxies in COSMOS}, interhash = {7add3d96db4e3b1e869f1b357a32dfb1}, intrahash = {3551bed881e290a1bed43a27de9e0177}, keywords = {galaxy gas high-z molecular sfr}, note = {cite arxiv:1505.02159Comment: submitted ApJ Letters}, timestamp = {2015-05-12T09:57:30.000+0200}, title = {ISM Masses and Star Formation at z = 1 to 6 ALMA Observations of Dust Continuum in 180 Galaxies in COSMOS}, url = {http://arxiv.org/abs/1505.02159}, year = 2015 }