Gas and Star Formation from HD and Dust Emission in a Strongly Lensed Galaxy

Abstract

The molecular gas content of high-redshift galaxies is a highly sought-after property. However, H${}_2$ is not directly observable in most environments, so its mass is probed through other emission lines (e.g., CO, [CI], [CII]), or through a gas-to-dust ratio. Each of these methods depends on several assumptions, and are best used in parallel. In this work, we extend an additional molecular gas tracer to high-redshift studies by observing hydrogen deuteride (HD) emission in the strongly lensed $z=5.656$ galaxy SPT0346-52 with ALMA. While no HD(1-0) emission is detected, we are able to place an upper limit on the gas mass of ${\mathrm{M}}_{{\mathrm{H}}_2}<6.4\times 10^{11}{\mathrm{M}}_{\odot }$. This is used to find a limit on the ${\mathrm{L}}_{\mathrm{CO}}^{\prime }$ conversion factor of ${\alpha }_{\mathrm{CO}}<5.8$ M${}_{\odot }$(K km s${}^{-1}$ pc${}^2$)${}^{-1}$. In addition, we construct the most complete spectral energy distribution (SED) of this source to date, and fit it with a single-temperature modified blackbody using the nested sampling code MultiNest, yielding a best-fit dust mass ${\mathrm{M}}_{\mathrm{dust}}=10^{8.92\pm 0.02}$ M${}_{\odot }$, dust temperature $78.6\pm 0.5$ K, dust emissivity spectral index $\beta =1.81\pm 0.03$, and star formation rate $\mathrm{SFR}=3800\pm 100$ M${}_{\odot }$ year${}^{-1}$. Using the continuum flux densities to estimate the total gas mass of the source, we find ${\mathrm{M}}_{{\mathrm{H}}_2}<2.4\times 10^{11}$ M${}_{\odot }$, assuming sub-solar metallicity. This implies a CO conversion factor of ${\alpha }_{\mathrm{CO}}<2.2$, which is between the standard values for MW-like galaxies and starbursts. These properties confirm that SPT0346-52 is a heavily starbursting, gas rich galaxy.

11 pages, 6 figures. Accepted for publication in MNRAS

References in corpus (21)

• Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample
• 350 Micron Dust Emission from High Redshift Quasars
• Mass measurements in protoplanetary disks from hydrogen deuteride
• The nature of the [CII] emission in dusty star-forming galaxies from the SPT survey
• A joint analysis of BLAST 250--500um and LABOCA 870um observations in the Extended Chandra Deep Field South
• ALMA Characterises the Dust Temperature of z ~ 5.5 Star-Forming Galaxies
• The properties of the interstellar medium of galaxies across time as traced by the neutral atomic carbon [CI]
• HD and H2 formation in low-metallicity dusty gas clouds at high redshift
• COLDz: A High Space Density of Massive Dusty Starburst Galaxies ~1 Billion Years after the Big Bang
• Deceptively cold dust in the massive starburst galaxy GN20 at $z\sim 4$
• HD molecules at high redshift: A low astration factor of deuterium in a solar-metallicity DLA system at z=2.418
• HD/H2 Molecular Clouds in the Early Universe: The Problem of Primordial Deuterium
• HD molecules at high redshift: The absorption system at z=2.3377 towards Q 1232+082
• SPT0346-52: Negligible AGN Activity in a Compact, Hyper-starburst Galaxy at z = 5.7
• Spitzer observations of hydrogen deuteride
• A multi-wavelength exploration of the [CII]/IR ratio in H-ATLAS/GAMA galaxies out to z=0.2
• [CI](1-0) and [CI](2-1) in resolved local galaxies
• HD/H2 as a probe of the roles of gas, dust, light, metallicity and cosmic rays in promoting the growth of molecular hydrogen in the diffuse interstellar medium
• Detection of a high-redshift molecular outflow in a primeval hyperstarburst galaxy
• Constraint on a varying proton-to-electron mass ratio from H2 and HD absorption at z = 2.34
• Source structure and molecular gas properties from high-resolution CO imaging of SPT-selected dusty star-forming galaxies

Cited by in corpus (6)

• Dual constraints with ALMA: new [O III] 88 $\mu$m and dust-continuum observations reveal the ISM conditions of luminous LBGs at $z\sim 7$
• An empirical study of dust properties at the earliest epochs
• Evidence of extended cold molecular gas and dust halos around $\mathbf{z}\sim 2.3$ Extremely Red Quasars with ALMA
• Multi-Phase ISM in the z = 5.7 Hyperluminous Starburst SPT0346-52
• IR characteristic emission and dust properties of star-forming galaxies at 4.5 $<$ z $<$ 6.2
• Bright [CII]158$\mu$m Streamers as a Beacon for Giant Galaxy Formation in SPT2349$-$56 at $z=4.3$