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تسجيل مستخدم جديدCensus of the Local Universe (CLU) Narrow-Band Survey I: Galaxy Catalogs from Preliminary Fields
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David O. Cook
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We present the Census of the Local Universe (CLU) narrow-band survey to search for emission-line (ha) galaxies. CLU-ha~has imaged $approx$3$pi$ of the sky (26,470~deg$^2$) with 4 narrow-band filters that probe a distance out to 200~Mpc. We have obtained spectroscopic follow-up for galaxy candidates in 14 preliminary fields (101.6~deg$^2$) to characterize the limits and completeness of the survey. In these preliminary fields, CLU can identify emission lines down to an ha~flux limit of $10^{-14}$~$rm{erg~s^{-1}~cm^{-2}}$ at 90% completeness, and recovers 83% (67%) of the ha~flux from catalogued galaxies in our search volume at the $Sigma$=2.5 ($Sigma$=5) color excess levels. The contamination from galaxies with no emission lines is 61% (12%) for $Sigma$=2.5 ($Sigma$=5). Also, in the regions of overlap between our preliminary fields and previous emission-line surveys, we recover the majority of the galaxies found in previous surveys and identify an additional $approx$300 galaxies. In total, we find 90 galaxies with no previous distance information, several of which are interesting objects: 7 blue compact dwarfs, 1 green pea, and a Seyfert galaxy; we also identified a known planetary nebula. These objects show that the CLU-ha~survey can be a discovery machine for objects in our own Galaxy and extreme galaxies out to intermediate redshifts. However, the majority of the CLU-ha~galaxies identified in this work show properties consistent with normal star-forming galaxies. CLU-ha~galaxies with new redshifts will be added to existing galaxy catalogs to focus the search for the electromagnetic counterpart to gravitational wave events.
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