Abstracts: Stacking Techniques in Wide-field Astronomy, 23-24 Feb 2010

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HI Stacking in the Local Universe - the CRUMBS project

Sarah Blyth (University of Cape Town) 

HI spectral stacking techniques, although usually associated with low
signal-to-noise observations at relatively high redshifts, can also be
applied to studying the Local Universe. The Nancay Interstellar Baryon
Legacy Extragalactic Survey (NIBLES) is a targeted survey of 3000 galaxies
in the Local Universe (900 < cz < 12000 km/s). In the CRUMBS project, we
have used stacking techniques to extract HI information for NIBLES galaxies
which were classified as non-detections (SNR <  3 sigma). The size of our
sample and optical information on the NIBLES galaxies has allowed us to
divide our sample according to a range of optical criteria. We will discuss
our co-adding method and present some results and mass limits for these
galaxies.

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HI in redshifted galaxy populations 

Frank Briggs/Philip Lah  (ANU) 

(no abstract available) 

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Unveiling the HI Universe with Spectral Stacking

Jacinta Delhaize  (UWA/ICRAR)

Understanding the evolution of galaxies is one of the goals of modern
cosmology and one of the five key science goals of the SKA. Neutral
hydrogen gas (HI) is a fundamental ingredient in galaxy evolution.
Unfortunately, due to the limits of current radio telescopes, the HI
universe beyond redshift zero will largely remain elusive until
facilities such as ASKAP and the SKA become available.

However, spectral stacking is a promising technique for pushing the
redshift boundary of 21cm HI detections. I will present the results
of a stacking analysis of Parkes observations of a 2dFGRS field near
the South Galactic Pole. A strong statistical detection is achieved
by stacking the HI spectra of approximately 4000 sources in this
field with 0.04