| Description: |
© 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 (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. |
| Relation: |
http://epubs.surrey.ac.uk/813861/; http://epubs.surrey.ac.uk/813861/15/Hydra%20II.pdf; http://epubs.surrey.ac.uk/813861/9/SRI_deposit_agreement.pdf; 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). |