The MeerKAT Absorption Line Survey (MALS)

Abstract

Deep galaxy surveys have revealed that the global star formation rate (SFR) density in the Universe peaks at 1 < z < 2 and sharply declines towards z = 0. But a clear picture of the underlying processes, in particular the evolution of cold atomic (~100 K) and molecular gas phases, that drive such a strong evolution is yet to emerge. MALS is designed to use MeerKAT's L- and UHF-band receivers to carry out the most sensitive (N(HI)>10${}^{19}$ cm${}^{-2}$) dust-unbiased search of intervening HI 21-cm and OH 18-cm absorption lines at 0 < z < 2. This will provide reliable measurements of the evolution of cold atomic and molecular gas cross-sections of galaxies, and unravel the processes driving the steep evolution in the SFR density. The large sample of HI and OH absorbers obtained from the survey will (i) lead to tightest constraints on the fundamental constants of physics, and (ii) be ideally suited to probe the evolution of magnetic fields in disks of galaxies via Zeeman Splitting or Rotation Measure synthesis. The survey will also provide an unbiased census of HI and OH absorbers, i.e. cold gas associated with powerful AGNs (>10${}^{24}$ W Hz${}^{-1}$) at 0 < z < 2, and will simultaneously deliver a blind HI and OH emission line survey, and radio continuum survey. Here, we describe the MALS survey design, observing plan and the science issues to be addressed under various science themes.

arXiv comment16 pages, 3 figures Accepted for publication, Proceedings of Science, Workshop on "MeerKAT Science: On the Pathway to the SKA", held in Stellenbosch 25-27 May, 2016

Cited by in corpus (14)

• First discoveries and localisations of Fast Radio Bursts with MeerTRAP: a real-time, commensal MeerKAT survey
• X-shooter observations of strong H${}_2$-bearing DLAs at high redshift
• FLASH Early Science -- Discovery of an intervening HI 21-cm absorber from an ASKAP survey of the GAMA 23 field
• The First Large Absorption Survey in HI (FLASH): I. Science Goals and Survey Design
• A new sample of southern radio galaxies: Host galaxy masses and star-formation rates
• Damped Ly-alpha Absorbers in Star-forming Galaxies at z < 0.15 Detected with the Hubble Space Telescope and Implications for Galaxy Evolution
• An ASKAP survey for HI absorption towards dust-obscured quasars
• Extragalactic HI 21-cm absorption line observations with the Five-hundred-meter Aperture Spherical radio Telescope
• MALS SALT-NOT survey of MIR-selected powerful radio-bright AGN at 0<z<3.5
• Spatially resolved Lyman-$\alpha$ emission around radio bright quasars
• OH in the diffuse interstellar medium: physical modelling and prospects with upcoming SKA precursor/pathfinder surveys
• Mapping HI 21-cm in the Klemola 31 group at z = 0.029: emission and absorption towards PKS2020-370
• Optimizing spectral stacking for 21-cm observations of galaxies: accuracy assessment and symmetrized stacking
• Discovery of a damped Ly$\alpha$ absorber originating in a spectacular interacting dwarf galaxy pair at $z=0.026$