J/A+A/642/L10 AGESVC1 282 deep optical image (Bilek+, 2020)
Deep optical imaging of the dark galaxy candidate AGESVC1 282.
Bilek M., Mueller O., Vudragovic A., Taylor R.
<Astron. Astrophys. 642, L10 (2020)>
=2020A&A...642L..10B 2020A&A...642L..10B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry ; Optical
Keywords: galaxies: individual: AGESVC1 282 - galaxies: formation -
techniques: image processing - galaxies: interactions -
galaxies: structure - galaxies: clusters: intracluster medium
Abstract:
The blind HI survey Arecibo Galaxy Environment Survey (AGES) detected
several unresolved sources in the Virgo cluster, which do not have
optical counterparts in the Sloan Digital Sky Survey. The origin of
these dark clouds is unknown. They might be crucial objects since they
could be the so-called dark galaxies, that is, the dark matter halos
without stellar content that are expected from cosmological
simulations. In order to reveal the nature of the dark clouds, we took
a deep optical image of one them, AGESVC1 282, with the
newly-commissioned 1.4m Milankovic Telescope. After observing it for
10.4h in the L-filter, the image reached a surface-brightness limit of
about 29.1mag/arcsec+2 in V. No optical counterpart was detected. We
placed an upper limit on the Vband luminosity of the object of
1.1x107L☉, giving a stellar mass below 1.4x107M☉ and a
HI-to-stellar mass ratio above 3.1. By inspecting archival HI
observations of the surrounding region, we found that none of the
standard explanations for optically dark HI clouds fits the available
constraints on this object.
Description:
April 2020 with the 1.4 meter Milankovic telescope equipped with an
Andor IKONL CCD camera from the Astronomical Station Vidojevica
(Serbia). Several images were taken with a 90 camera rotation. Sky
flat field images were taken for both regular and rotated camera
positions. A total of 125 images were taken in the luminance L-filter
with a 300s exposure each. The integrated exposure time was 10.4 hrs.
Figure_1.fits presents fully stacked and calibrated image. The image
is centered on the dark cloud AGESVC1 282. The field-of-view is
21.9'x22.7'. The box indicates the stamps presented in Figure 1. The
black line shows the scale at an assumed distance of 23Mpc.
Objects:
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RA (2000) DE Designation(s)
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12 25 24.10 +08 16 54.0 AGESVC1 282 = [TDA2012] AGESVC1 282
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 101 1 Information on fits image
fits/* . 1 fits image
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See also:
J/MNRAS/423/787 : AGES sources in Virgo cluster (Taylor+, 2012)
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- 24 F5.3 arcsec/pix scale Scale of the image
26- 29 I4 --- Nx Number of pixels along X-axis
31- 34 I4 --- Ny Number of pixels along Y-axis
36- 40 I5 Kibyte size Size of FITS file
42- 54 A13 --- FileName Name of FITS file, in subdirectory fits
56-101 A46 --- Title Title of the FITS file
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Acknowledgements:
Michal Bilek, bilek(at)astro.unistra.fr
(End) Michal Bilek [Strasbourg Obs.], Patricia Vannier [CDS] 26-Sep-2020