| Name: | Ananthamoorthy B |
| Affiliation: | Manipal Centre for Natural Sciences, Centre of Excellence, Manipal Academy of Higher Education, Manipal, Karnataka, India |
| Conference ID : | ASI2024_501 |
| Title : | UVIT faint source catalog in light of the Poisson distribution of background |
| Authors : | B. Ananthamoorthy1, Debbijoy Bhattacharya1, P. Sreekumar1, C. S. Stalin2 |
| Authors Affiliation: | 1 B. Ananthamoorthy, Debbijoy Bhattacharya, P. Sreekumar Affiliation(Manipal Centre for Natural Sciences, Centre of Excellence, Manipal Academy of Higher Education, Manipal, Karnataka-576104, India)
2 C. S. Stalin Affiliation(Indian Institute of Astrophysics, Bengaluru, Karnataka-560034, India) |
| Mode of Presentation: | Poster |
| Abstract Category : | Galaxies and Cosmology |
| Abstract : | UVIT onboard AstroSat observes the universe in the FUV (130-180 nm) and NUV (200-300 nm) regimes of the electromagnetic spectrum with the best resolution of 1.2 to 1.5 arcsec in FUV (~3 times better than its predecessor GALEX). As the UV backgrounds of astrophysical origin are typically low in the order of 10^(-3) to 10^(-4) photons/s/arcsec^(2), the UV background from UVIT is expected to follow the Poisson distribution. The count distribution of the source-free regions in a few UVIT fields in fact closely follows the Poisson distribution. Therefore, we considered the Poissonian nature of the background for the background and threshold calculations and carried out the detection of UVIT sources. Two test cases lacking crowded source regions, M31 Field 13 and SMC, were taken up to implement this approach. Our source listings contain most of the previously reported sources, but more importantly, we detect many more additional sources at fainter magnitudes, most of which have counterparts in deep observation catalogs at other wavebands. The presence of counterparts adds confidence that these sources are indeed real. This work extends the magnitude limit for the detection of sources from UVIT, which can greatly expand the final UV source catalog from the ongoing AstroSat mission.
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