Bibcode
Martin, N. F.; Nidever, David L.; Besla, Gurtina; Olsen, Knut; Walker, Alistair R.; Vivas, A. Katherina; Gruendl, Robert A.; Kaleida, Catherine C.; Muñoz, Ricardo R.; Blum, Robert D.; Saha, Abhijit; Conn, Blair C.; Bell, Eric F.; Chu, You-Hua; Cioni, Maria-Rosa L.; de Boer, Thomas J. L.; Gallart, C.; Jin, Shoko; Kunder, Andrea; Majewski, Steven R.; Martinez-Delgado, David; Monachesi, Antonela; Monelli, M.; Monteagudo, L.; Noël, Noelia E. D.; Olszewski, Edward W.; Stringfellow, Guy S.; van der Marel, Roeland P.; Zaritsky, Dennis
Bibliographical reference
The Astrophysical Journal Letters, Volume 804, Issue 1, article id. L5, 6 pp. (2015).
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5
2015
Citations
143
Refereed citations
135
Description
We present the discovery of a new dwarf galaxy, Hydra II, found
serendipitously within the data from the ongoing Survey of the
Magellanic Stellar History conducted with the Dark Energy Camera on the
Blanco 4 m Telescope. The new satellite is compact ({{r}h}=68
± 11 pc) and faint ({{M}V}=-4.8 ± 0.3), but
well within the realm of dwarf galaxies. The stellar distribution of
Hydra II in the color–magnitude diagram is well-described by a
metal-poor ([Fe/H]=-2.2) and old (13 Gyr) isochrone and shows a distinct
blue horizontal branch, some possible red clump stars, and faint stars
that are suggestive of blue stragglers. At a heliocentric distance of
134 ± 10 kpc, Hydra II is located in a region of the Galactic
halo that models have suggested may host material from the leading arm
of the Magellanic Stream. A comparison with N-body simulations hints
that the new dwarf galaxy could be or could have been a satellite of the
Magellanic Clouds.
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Galaxy Evolution in the Local Group
Galaxy formation and evolution is a fundamental Astrophysical problem. Its study requires “travelling back in time”, for which there are two complementary approaches. One is to analyse galaxy properties as a function of red-shift. Our team focuses on the other approach, called “Galactic Archaeology”. It is based on the determination of galaxy
Matteo
Monelli