ﻻ يوجد ملخص باللغة العربية
We test the use of long-wavelength dust continuum emission as a molecular gas tracer at high redshift, via a unique sample of 12, z~2 galaxies with observations of both the dust continuum and CO(1-0) line emission (obtained with the Atacama Large Millimeter Array and Karl G. Jansky Very Large Array, respectively). Our work is motivated by recent, high redshift studies that measure molecular gas masses (ensuremath{rm{M}_{rm{mol}}}) via a calibration of the rest-frame $850mu$m luminosity ($L_mathrm{850mu m,rest}$) against the CO(1-0)-derived ensuremath{rm{M}_{rm{mol}}} of star-forming galaxies. We hereby test whether this method is valid for the types of high-redshift, star-forming galaxies to which it has been applied. We recover a clear correlation between the rest-frame $850mu$m luminosity, inferred from the single-band, long-wavelength flux, and the CO(1-0) line luminosity, consistent with the samples used to perform the $850mu$m calibration. The molecular gas masses, derived from $L_mathrm{850mu m,rest}$, agree to within a factor of two with those derived from CO(1-0). We show that this factor of two uncertainty can arise from the values of the dust emissivity index and temperature that need to be assumed in order to extrapolate from the observed frequency to the rest-frame at 850$mathrm{mu m}$. The extrapolation to 850$mathrm{mu m}$ therefore has a smaller effect on the accuracy of Mmol derived via single-band dust-continuum observations than the assumed CO(1-0)-to-ensuremath{rm{M}_{rm{mol}}} conversion factor. We therefore conclude that single-band observations of long-wavelength dust emission can be used to reliably constrain the molecular gas masses of massive, star-forming galaxies at $zgtrsim2$.
We report the detection of CO(1-0) emission in the strongly lensed high-redshift quasars IRAS F10214+4724 (z=2.286), the Cloverleaf (z=2.558), RX J0911+0551 (z=2.796), SMM J04135+10277 (z=2.846), and MG 0751+2716 (z=3.200), using the Expanded Very La
We present new ALMA observations aimed at mapping molecular gas reservoirs through the CO(3-2) transition in three quasars at $zsimeq2.4$, LBQS 0109+0213, 2QZ J002830.4-281706, and [HB89] 0329-385. Previous [OIII]5007 observations of these quasars sh
We present an extremely deep CO(1-0) observation of a confirmed $z=1.62$ galaxy cluster. We detect two spectroscopically confirmed cluster members in CO(1-0) with $S/N>5$. Both galaxies have log(${cal M_{star}}$/msol)$>11$ and are gas rich, with ${ca
We present CO(1-0) observations of the high-redshift quasi-stellar objects (QSOs) BR 1202-0725 (z=4.69), PSS J2322+1944 (z=4.12), and APM 08279+5255 (z=3.91) using the NRAO Green Bank Telescope (GBT) and the MPIfR Effelsberg 100m telescope. We detect
Post-starburst (or E+A) galaxies are characterized by low H$alpha$ emission and strong Balmer absorption, suggesting a recent starburst, but little current star formation. Although many of these galaxies show evidence of recent mergers, the mechanism