The Phoenix stream: a cold stream in the Southern Hemisphere

Balbinot, E, Yanny, B, Li, T S, Santiago, B, Marshall, J L, Finley, D A, Pieres, A, Abbott, T M C, Abdalla, F B, Allam, S, Benoit-Lévy, A, Bernstein, G M, Bertin, E, Brooks, D, Burke, D L, Carnero Rosell, A, Carrasco Kind, M, Carretero, J, Cunha, C E, Da Costa, L N, DePoy, D L, Desai, S, Diehl, H T, Doel, P, Estrada, J, Flaugher, B, Frieman, J, Gerdes, D W, Gruen, D, Gruendl, R A, Honscheid, K, James, D J, Kuehn, K, Kuropatkin, N, Lahav, O, March, M, Martini, P, Miquel, R, Nichol, R C, Ogando, R, Romer, A K, Sanchez, E, Schubnell, M, Sevilla-Noarbe, I, Smith, R C, Soares-Santos, M, Sobreira, F, Suchyta, E, Tarle, G, Thomas, D, Tucker, D and Walker, A R (2016) The Phoenix stream: a cold stream in the Southern Hemisphere. Astrophysical Journal, 820 (1). p. 58. ISSN 1538-435

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We report the discovery of a stellar stream in the Dark Energy Survey Year 1 (Y1A1) data. The discovery was made through simple color-magnitude filters and visual inspection of the Y1A1 data. We refer to this new object as the Phoenix stream, after its resident constellation. After subtraction of the background stellar population we detect a clear signal of a simple stellar population. By fitting the ridge line of the stream in color-magnitude space, we find that a stellar population with age tau = 11.5 ± 0.5 Gyr and [Fe/H] < -1.6, located 17.5 ± 0.9 kpc from the Sun, gives an adequate description of the stream stellar population. The stream is detected over an extension of 8.°1 (2.5 kpc) and has a width of ˜54 pc assuming a Gaussian profile, indicating that a globular cluster (GC) is a probable progenitor. There is no known GC within 5 kpc that is compatible with being the progenitor of the stream, assuming that the stream traces its orbit. We examined overdensities (ODs) along the stream, however, no obvious counterpart-bound stellar system is visible in the coadded images. We also find ODs along the stream that appear to be symmetrically distributed---consistent with the epicyclic OD scenario for the formation of cold streams---as well as a misalignment between the northern and southern part of stream. Despite the close proximity we find no evidence that this stream and the halo cluster NGC 1261 have a common accretion origin linked to the recently found EriPhe OD.

Item Type: Article
Keywords: Galaxy: halo – Galaxy: structure
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy
Depositing User: Richard Chambers
Date Deposited: 05 May 2016 12:50
Last Modified: 22 Mar 2017 01:12

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Project NameSussex Project NumberFunderFunder Ref
Astrophysics and Cosmology - Sussex Consolidated GrantG1291STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/L000652/1