Deep, high-resolution observations of the Hubble Flanking Field region


Very little is known about the spatial distribution of neutral gas in damped Lyman-# systems (DLAs), despite their importance in understanding galaxy evolution. We propose a sensitive global VLBI experiment to simultaneously map redshifted 21cm absorption in two low redshift DLAs towards B0738+313. Both absorbers have multiple 21cm absorption components, in kinematically cold and warm gas phases, and the background QSO is known to be extended over # 30 mas (# 50 pc and # 105 pc at the two DLA redshifts). The proposed observations will enable us to probe the spatial distribution of the absorbing HI clouds, and to determine whether both the warm and cold phases cover the entire radio source. In the lower redshift absorber, a comparison between the 21cm optical depths seen on VLBI and WSRT baselines will also allow us to estimate or limit the HI mass of the host galaxy

Name Other * Institution Email Phone
Wendy Lane PI Naval Research Lab 202-404-1387
Nissim Kanekar NRAO-AOC 1 505 835 7334
Frank Briggs ANU
Rene Vermeulen Stichting ASTRON 011 31-521-595262
* PI = Principal Investigator; CO = Contact author; T = Thesis observations; S = Student

Front Ends
Gregorian L(1.15 to 1.73 GHz)

Back Ends
Mark 5 recorder (disks)

Type of Observing
Very Long Baseline Interferometry

Switching Type

Processor (correlator)

Allotted time 12.00 hours

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Updated 09/19/2007