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The HST Large Programme on NGC 6752. I. Serendipitous discovery of a dwarf Galaxy in background
Author
Bedin, L RSalaris, M
Rich, R M
Richer, H
Anderson, J
Bettoni, D
Nardiello, D
Milone, A P
Marino, A F
Libralato, M
Bellini, A
Dieball, A
Bergeron, P
Burgasser, A J
Apai, D
Affiliation
Univ Arizona, Dept AstronUniv Arizona, Steward Observ
Univ Arizona, Lunar & Planetary Lab
Issue Date
2019-01-10
Metadata
Show full item recordPublisher
OXFORD UNIV PRESSCitation
L R Bedin, M Salaris, R M Rich, H Richer, J Anderson, D Bettoni, D Nardiello, A P Milone, A F Marino, M Libralato, A Bellini, A Dieball, P Bergeron, A J Burgasser, D Apai, The HST Large Programme on NGC 6752. I. Serendipitous discovery of a dwarf Galaxy in background, Monthly Notices of the Royal Astronomical Society: Letters, Volume 484, Issue 1, March 2019, Pages L54–L58, https://doi.org/10.1093/mnrasl/slz004Rights
Copyright © 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
As part of a large Hubble Space Telescope investigation aiming at reaching the faintest stars in the Galactic globular cluster NGC 6752, an Advanced Camera for Surveys/Wide Field Channel field was the subject of deep optical observations reaching magnitudes as faint as V ∼ 30. In this field, we report the discovery of Bedin I, a dwarf spheroidal galaxy too faint and too close to the core of NGC 6752 for detection in earlier surveys. As it is of broad interest to complete the census of galaxies in the local Universe, in this letter we provide the position of this new object along with preliminary assessments of its main parameters. Assuming the same reddening as for NGC 6752, we estimate a distance modulus of (m − M)0 = 29.70 ± 0.13 from the observed red giant branch, i.e. 8.7+0.5−0.7 Mpc, and size of ∼840 × 340 pc, about one-fifth the size of the Large Magellanic Cloud. A comparison of the observed colour–magnitude diagram with synthetic counterparts, which account for the galaxy distance modulus, reddening, and photometric errors, suggests the presence of an old (∼13 Gyr) and metal-poor ([Fe/H] ∼ −1.3) population. This object is most likely a relatively isolated satellite dwarf spheroidal galaxy of the nearby great spiral NGC 6744, or potentially the most distant isolated dwarf spheroidal known with a secure distance.ISSN
0035-8711Version
Final published versionSponsors
NASA [NAS 5-26555]; European Research Council (ERC) under the European Union's Horizon 2020 research innovation programme (Grant Agreement ERC-StG 2016) [716082]; MIUR through the the FARE project [R164RM93XW]; European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant [797100];[HST-GO-15096]ae974a485f413a2113503eed53cd6c53
10.1093/mnrasl/slz004