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Hydra II: A Faint and Compact Milky Way Dwarf Galaxy Found in the Survey of the Magellanic Stellar History

Martin, NF, Nidever, DL, Besla, G, Olsen, K, Walker, AR, Vivas, AK, Gruendl, RA, Kaleida, CC, Muñoz, RR, Blum, RD , Saha, A, Conn, BC, Bell, EF, Chu, YH, Cioni, MRL, De Boer, TJL, Gallart, C, Jin, S, Kunder, A, Majewski, SR, Martinez-Delgado, D, Monachesi, A, Monelli, M, Monteagudo, L, Noël, NED, Olszewski, EW, Stringfellow, GS, Van Der Marel, RP and Zaritsky, D (2015) Hydra II: A Faint and Compact Milky Way Dwarf Galaxy Found in the Survey of the Magellanic Stellar History Astrophysical Journal Letters, 804 (1).

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© 2015. The American Astronomical Society. All rights reserved.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 (rh = 68 ± 11 pc) and faint (MV = -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.

Item Type: Article
Subjects : Physics
Divisions : Faculty of Engineering and Physical Sciences > Physics
Authors :
Martin, NF
Nidever, DL
Besla, G
Olsen, K
Walker, AR
Vivas, AK
Gruendl, RA
Kaleida, CC
Muñoz, RR
Blum, RD
Saha, A
Conn, BC
Bell, EF
Chu, YH
Cioni, MRL
De Boer, TJL
Gallart, C
Jin, S
Kunder, A
Majewski, SR
Martinez-Delgado, D
Monachesi, A
Monelli, M
Monteagudo, L
Noël, NED
Olszewski, EW
Stringfellow, GS
Van Der Marel, RP
Zaritsky, D
Date : 1 May 2015
DOI : 10.1088/2041-8205/804/1/L5
Copyright Disclaimer : © 2015. The American Astronomical Society. All rights reserved.
Uncontrolled Keywords : Galaxies: individual (Hydra II) ; Local Group; Magellanic Clouds
Depositing User : Symplectic Elements
Date Deposited : 30 Mar 2017 14:50
Last Modified : 30 Mar 2017 14:50

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