J/A+A/629/L2 [TT2009] 25 vicinity VI photometry (Mueller+, 2019)
Distance to the nearby dwarf galaxy [TT2009] 25 in the NGC891 group using the
tip of the red giant branch.
Mueller O., Ibata R., Rejkuba M., Posti L.
<Astron. Astrophys. 629, L2 (2019)>
=2019A&A...629L...2M 2019A&A...629L...2M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Galaxies, photometry
Keywords: galaxies: dwarf - galaxies: distances and redshifts -
galaxies: groups: individual: NGC 891 -
galaxies: individual: [TT2009] 25
Abstract:
Dwarf galaxies are key objects for small-scale cosmological tests like
the abundance problems or the planes-of-satellites problem. A crucial
task is therefore to get accurate information for as many nearby dwarf
galaxies as possible. Using extremely deep, groundbased V and i-band
Subaru Suprime Cam photometry with a completeness of i=27mag, we
measure the distance of the dwarf galaxy [TT2009] 25 using the tip of
the red giant branch (RGB) as a standard candle. This dwarf resides in
the field around the Milky Way-analog NGC891. Using a Bayesian
approach, we measure a distance of 10.28Mpc, which is consistent with
the distance of NGC891, and thus confirm it as a member of NGC891. The
dwarf galaxy follows the scaling relations defined by the Local Group
dwarfs. We do not find an extended stellar halo around [TT2009] 25. In
the small field of view of 100kpc covered by the survey, only one
bright dwarf galaxy and the giant stream are apparent. This is
comparable to the Milky Way, where one bright dwarf resides in the
same volume, as well as the Sagittarius stream - excluding
satellites which are farther away but would be projected in the
line-of-sight. It is thus imperative to survey for additional dwarf
galaxies in a larger area around NGC891 to test the abundance of dwarf
galaxies and compare this to the number of satellites around the Milky
Way.
Description:
The data were taken with the Subaru Suprime Camera in Gunn i and
Johnson V band. We transformed to photometry into AB magnitudes. The
table compiles: RA, dec, V, V_error, i, i_error, CHI, sharp for the
vicinity of the dwarf galaxy [TT2009] 25.
Objects:
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RA (2000) DE Designation(s)
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02 21 12.1 +42 21 51 [TT2009] 25 = GSC2.3 NCIA018969
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
photom.dat 67 570 [TT2009] 25 vicinity VI photometry
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Byte-by-byte Description of file: photom.dat
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Bytes Format Units Label Explanations
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1- 11 F11.8 deg RAdeg Right ascension (J2000)
13- 23 F11.8 deg DEdeg Declination (J2000)
25- 31 F7.4 mag Vmag ?=99.9915 Johnson V magnitude (AB)
33- 37 F5.3 mag e_Vmag ?=0 rms uncertainty on V magnitude
39- 45 F7.3 mag imag ?=100.484 Gunn i magnitude (AB)
47- 51 F5.3 mag e_imag ?=0 rms uncertainty on i magnitude
53- 59 F7.3 --- chi ?=999.999 CHI estimation from DAOPHOT
61- 67 F7.3 --- Sharp ?=999.999 Sharp estimation from DAOPHOT
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Acknowledgements:
Oliver Mueller, oliver.muller(at)astro.unistra.fr
(End) Patricia Vannier [CDS] 12-Aug-2019