| Abstract : | We present a photometric analysis of Great Observatories Origins Survey (GOODS) northern deep field using UVIT F154W, N242W, and N245M band observations. Using the deep imaging, we reached a 3 sigma detection limit of ~28 mag in all the three filters. We used SExtractor and estimated the UV sky background by sampling the entire field iteratively with different detection thresholds. We noticed around 10% variation of the mean background across the 28' UVIT field. We examined the nature of PSF in all the bands by fitting a combination of Moffat (for core) and exponential (for wing) function. Both the FWHM and the ellipticity of the PSF stars show an increasing trend from centre to outside of the field with ranges between 1.0 - 1.4 arcsec and 0.85 - 0.99 respectively. The photometry was carried out on the background subtracted images using a reference detection image. We identified around 6000 objects within the HST covered GOODS-north field and produced a catalog listing their position, magnitude in multiple apertures, kron radius, flux radius. We used UVIT N242W band photometry along with HST F275W, F336W and KPNO U band to estimate UV spectral slope of galaxies between redshift ~ 0.3 - 0.8. The measured beta slope has a mean value ~ -1.4 with no significant evolution within the redshift range. |
