Pegasus V/Andromeda XXXIV–a newly discovered ultrafaint dwarf galaxy on the outskirts of Andromeda
| Autor: | Michelle L M Collins, Emily J E Charles, David Martínez-Delgado, Matteo Monelli, Noushin Karim, Giuseppe Donatiello, Erik J Tollerud, Walter Boschin |
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| Přispěvatelé: | Ministerio de Ciencia e Innovación (España), Junta de Andalucía |
| Rok vydání: | 2022 |
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| Zdroj: | Monthly Notices of the Royal Astronomical Society: Letters. 515:L72-L77 |
| ISSN: | 1745-3933 1745-3925 |
| Popis: | We report the discovery of an ultrafaint dwarf in the constellation of Pegasus. Pegasus V (Peg V)/Andromeda XXXIV was initially identified in the public imaging data release of the DESI Legacy Imaging Surveys and confirmed with deep imaging from Gemini/GMOS-N. The colour–magnitude diagram shows a sparse red giant branch (RGB) population and a strong overdensity of blue horizontal branch stars. We measure a distance to Peg V of D=692+33−31 kpc, making it a distant satellite of Andromeda with MV = −6.3 ± 0.2 and a half-light radius of rhalf = 89 ± 41 pc. It is located ∼260 kpc from Andromeda in the outskirts of its halo. The RGB is well fitted by a metal-poor isochrone with [Fe/H] = −3.2, suggesting it is very metal poor. This, combined with its blue horizontal branch, could imply that it is a reionization fossil. This is the first detection of an ultrafaint dwarf outside the deep Pan-Andromeda Archaeological Survey area, and points to a rich, faint satellite population in the outskirts of our nearest neighbour. © 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. DMD acknowledges financial support from the Talentia Senior Program (through the incentive ASE-136) from Secretaría General de Universidades, Investigación y Tecnología, de la Junta de Andalucía. DMD acknowledges funding from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709) and project (PDI2020-114581GB-C21/AEI/10.13039/501100011033). |
| Databáze: | OpenAIRE |
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