Evolution of damped Lyman alpha kinematics and the effect of spatial resolution on 21-cm measurements

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dc.creatorRyan-Weber, Emma V.
dc.creatorStaveley-Smith, Lister
dc.creatorWebster, Rachel L.
dc.date2005-10-19
dc.date.accessioned2026-07-07T06:43:57Z
dc.date.available2026-07-07T06:43:57Z
dc.descriptionWe have investigated the effect of spatial resolution on determining pencil-beam like velocity widths and column densities in galaxies. Three 21-cm datasets are used, the HIPASS galaxy catalogue, a subset of HIPASS galaxies with ATCA maps and a high-resolution image of the LMC. Velocity widths measured from 21-cm emission in local galaxies are compared with those measured in intermediate redshift Damped Lyman alpha (DLA) absorbers. We conclude that spatial resolution has a severe effect on measuring pencil-beam like velocity widths in galaxies. Spatial smoothing by a factor of 240 is shown to increase the median velocity width by a factor of two. Thus any difference between velocity widths measured from global profiles or low spatial resolution 21-cm maps at z=0 and DLAs at z>1 cannot unambiguously be attributed to galaxy evolution. The effect on column density measurements is less severe and the values of dN/dz from local low-resolution 21-cm measurements are expected to be overestimated by only ~10 per cent.
dc.description5 pages, 6 figures, accepted for publication in MNRAS letters
dc.identifierhttps://arxiv.org/abs/astro-ph/0510555
dc.identifierhttp://arxiv.org/abs/astro-ph/0510555
dc.identifierMon.Not.Roy.Astron.Soc.Lett. 364 (2005) L51-L55
dc.identifierdoi:10.1111/j.1745-3933.2005.00104.x
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/102612
dc.subjectAstrophysics
dc.titleEvolution of damped Lyman alpha kinematics and the effect of spatial resolution on 21-cm measurements
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