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We use the GALEX (Galaxy Evolution Explorer) Medium Imaging Survey (MIS) and All-Sky Imaging Survey (AIS) data available in the first internal release, matched to the SDSS catalogs in the overlapping regions, to classify objects by comparing the multi-band photometry to model colors. We show an example of the advantage of such broad wavelength coverage (GALEX far-UV and near-UV, SDSS ugriz) in classifying objects and augmenting the existing samples and catalogs. From the MIS [AIS] sample over an area of 75 [92] square degrees, we select a total of 1736 [222] QSO candidates at redshift less than 2, significantly extending the number of fainter candidates, and moderately increasing the number of bright objects in the SDSS list of spectroscopically confirmed QSO. Numerous hot stellar objects are also revealed by the UV colors, as expected.
We investigate the quality of associations of astronomical sources from multi-wavelength observations using simulated detections that are realistic in terms of their astrometric accuracy, small-scale clustering properties and selection functions. We
Machine learning techniques, specifically the k-nearest neighbour algorithm applied to optical band colours, have had some success in predicting photometric redshifts of quasi-stellar objects (QSOs): Although the mean of differences between the spect
We use the Galaxy Evolution Explorer (GALEX) Medium and All-Sky-Imaging Survey (MIS & AIS) data from the first public data release (GR1), matched to the Sloan Digital Sky Survey (SDSS) DR3 catalog, to perform source classification. The GALEX surveys
At present, the precision of deep ultraviolet photometry is somewhat limited by the dearth of faint ultraviolet standard stars. In an effort to improve this situation, we present a uniform catalog of eleven new faint (u sim17) ultraviolet standard st
Digital co-addition of astronomical images is a common technique for increasing signal-to-noise and image depth. A modification of this simple technique has been applied to the detection of minor bodies in the Solar System: first stationary objects a