J/AJ/168/22 Faint sources, using Poisson Distribution (Ananthamoorthy+, 2024)
Detection of Faint Sources by the UltraViolet Imaging Telescope Onboard AstroSat
Using Poisson Distribution of Background.
Ananthamoorthy B., Bhattacharya D., Sreekumar P., Swathi B.
<Astron. J., 168, 22 (2024)>
=2024AJ....168...22A 2024AJ....168...22A
ADC_Keywords: Magellanic Clouds; Photometry, ultraviolet
Keywords: Ultraviolet astronomy ; Celestial objects catalogs ; Poisson
distribution ; Small Magellanic Cloud ; Andromeda galaxy
Abstract:
We present an improved approach for constructing the UV source
catalogs using observations from the UltraViolet Imaging Telescope
(UVIT) onboard AstroSat, by considering the Poisson distribution of
the UV background. The method is tested extensively using fields that
are not crowded, the Small Magellanic Cloud and M31 (Field 13). The
results are compared with previous studies that used UVIT
observations. This approach is successful in detecting fainter sources
and produces a large number of new sources (∼15% -92% more). Most of
the newly discovered UV sources fall in the faint end of the source
distribution (m≳22). The counterparts at other wavelengths are
identified for most sources. This approach is more efficient for
source detection and provides an opportunity to explore new classes of
UV sources.
Description:
UVIT onboard AstroSat telescope consists of two Ritchey-Chretien
telescopes, which observe in FUV (130-180nm) and NUV (200-300nm). It
has a field of view (FOV) of 14' radius and a resolution of ∼1.2-1.5"
with a plate-scale of 0.416".
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 71 25134 The catalog of UV sources in SMC and M31 Field 13
PHAT survey overlapping region
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See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
II/335 : Revised catalog of GALEX UV sources (GUVcat_AIS GR6+7) (Bianchi+ 2017)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJ/724/1389 : Mapping the diffuse UV sky with GALEX (Murthy+, 2010)
J/MNRAS/411/2770 : Hot white dwarfs in GALEX-DR5 (Bianchi+, 2011)
J/ApJS/215/9 : PHAT X. UV-IR photometry of M31 stars (Williams+, 2014)
J/ApJS/247/47 : Ultraviolet survey M31 with UVIT on AstroSat (Leahy+, 2020)
J/AJ/161/215 : Far-ultraviolet variable sources in M31 (Leahy+, 2021)
J/ApJS/264/40 : AstroSat UV GOODS-N Deep Field cat. (AUDFn) (Mondal+, 2023)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 27 A27 --- ID Source ID (1)
29- 34 A6 --- Field Field of observation
36- 40 A5 --- Filt UVIT filter identifier (2)
42- 49 F8.5 deg RAdeg [11/19] Right Ascension in decimal degrees (J2000)
51- 59 F9.5 deg DEdeg [-72/42] Declination in decimal degrees (J2000)
61- 65 F5.2 mag ABmag [14/23.9] AB magnitude in Filter
67- 71 F5.3 mag e_ABmag [0.002/0.5] Error in ABmag
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Note (1): In the form 'UVIT+<UVIT filter
identifier>+J++'.
Note (2): Full observational Filter details are in Table 1.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 16-Aug-2024