J/A+A/707/A248 UVIT Observtaion of HCG 77 (Srivastava+, 2026)
AstroSat-UVIT observations of a possibly interacting pair of galaxies in HCG 77.
Srivastava A., Jassal H.K., Gulati M., Singh K.P.
<Astron. Astrophys. 707, A248 (2026)>
=2026A&A...707A.248S 2026A&A...707A.248S (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, interacting ; Ultraviolet
Keywords: techniques: image processing - galaxies: dwarf -
galaxies: groups: general - galaxies: interactions -
galaxies: photometry - ultraviolet: general
Abstract:
Interactions and mergers possibly enhance the star formation in dwarf
galaxies in a group environment.
We aim to study star-forming regions and the spectral energy
distribution of two possibly interacting galaxies, PGC 56121 and PGC
56125, in the Hickson Compact Group 77.
We utilized the far-ultraviolet (FUV) channel of the Ultra Violet
Imaging Telescope (UVIT) on board AstroSat to observe and produce FUV
images of the galaxies. Our FUV images are at a much higher resolution
in comparison to those obtained from previous galaxy surveys by GALEX
in the near-UV and those from PS-1, DSS.
We have identified several star-forming regions in the two possibly
interacting galaxies, PGC 56121 and PGC 56125. These two galaxies form
a pair widely separated in redshift and are seen in projection. We
also report the presence of a candidate tidal dwarf galaxy at the end
of one of the tidal tails located to the east of the pair, and we
identified three major star-forming regions in the tidal dwarf. The
spectral energy distribution of three galaxies in the system is
presented and analyzed to investigate the key physical properties,
such as stellar mass, dust mass, total luminosity, and star formation
history, of the three galaxies. Based on these observations and on a
comparison with observations in radio, these three galaxies are
probably part of a small group of interacting galaxies.
Description:
We provide reduced far-ultraviolet FITS image obtained with the Ultra
Violet Imaging Telescope (UVIT) onboard AstroSat. The image
corresponds to observations of galaxies in the Hickson Compact Group
HCG 77. The data products are final science-ready images that were
used in the analysis presented in the associated A&A paper and are
provided for reuse by the community.
Final reduced AstroSat-UVIT FUV image of HCG 77.
The FITS header contains complete observational, instrumental, and
astrometric (WCS) information.
Objects:
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RA (2000) DE Designation(s)
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15 49 17.00 +21 49 41.9 HCG 77 = HCG 77
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 86 1 Information on fits image
fits/* . 1 fits image
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 35 I6 Kibyte size Size of FITS file
37- 62 A26 --- FileName Name of FITS file, in subdirectory fits
64- 86 A23 --- Title Title of the FITS file
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Acknowledgements:
Anshul Srivastava, ph23032(at)iisermohali.ac.in, anshuls.physics(at)gmail.com
(End) Patricia Vannier [CDS] 25-Jan-2026