Abstract
We have conducted the first blind HI survey covering 480 deg^2 and a
heliocentric velocity range from 300-1900 km/s to investigate the HI content of
the nearby spiral-rich Ursa Major region and to look for previously
uncatalogued gas-rich objects. Here we present the catalog of HI sources. The
HI data were obtained with the 4-beam receiver mounted on the 76.2-m Lovell
telescope (FWHM 12 arcmin) at the Jodrell Bank Observatory (UK) as part of the
HI Jodrell All Sky Survey (HIJASS). We use the automated source finder DUCHAMP
and identify 166 HI sources in the data cubes with HI masses in the range of
10^7 - 10^10.5 M_sun. Our Ursa Major HI catalogue includes 10 first time
detections in the 21-cm emission line.
We identify optical counterparts for 165 HI sources (99 per cent). For 54 HI
sources (33 per cent) we find numerous optical counterparts in the HIJASS beam,
indicating a high density of galaxies and likely tidal interactions. Four of
these HI systems are discussed in detail.
We find only one HI source (1 per cent) without a visible optical counterpart
out of the 166 HI detections. Green Bank Telescope (FWHM 9 arcmin) follow-up
observations confirmed this HI source and its HI properties. The nature of this
detection is discussed and compared to similar sources in other HI surveys.
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