DISCOVERY OF A STELLAR OVERDENSITY IN ERIDANUS-PHOENIX IN THE DARK ENERGY SURVEY Academic Article uri icon

abstract

  • ABSTRACT We report the discovery of an excess of main-sequence turnoff stars in the direction of the constellations of Eridanus and Phoenix from the first-year data of the Dark Energy Survey (DES). The EridanusPhoenix (EriPhe) overdensity is centered around l ∼ 285 ° ?> and b ∼ − 60 ° ?> and spans at least 30 in longitude and 10 in latitude. The Poisson significance of the detection is at least 9 &sgr; ?> . The stellar population in the overdense region is similar in brightness and color to that of the nearby globular cluster NGC 1261, indicating that the heliocentric distance of EriPhe is about m{kpc}}$?> d ∼ 16 kpc ?> . The extent of EriPhe in projection is therefore at least 4 kpc by 3 kpc. On the sky, this overdensity is located between NGC 1261 and a new stellar stream discovered by DES at a similar heliocentric distance, the so-called Phoenix Stream. Given their similar distance and proximity to each other, it is possible that these three structures may be kinematically associated. Alternatively, the EriPhe overdensity is morphologically similar to the Virgo overdensity and the HerculesAquila cloud, which also lie at a similar Galactocentric distance. These three overdensities lie along a polar plane separated by 120 and may share a common origin. Spectroscopic follow-up observations of the stars in EriPhe are required to fully understand the nature of this overdensity.

published proceedings

  • ASTROPHYSICAL JOURNAL

altmetric score

  • 2.25

author list (cited authors)

  • Li, T. S., Balbinot, E., Mondrik, N., Marshall, J. L., Yanny, B., Bechtol, K., ... Zhang, Y.

citation count

  • 42

complete list of authors

  • Li, TS||Balbinot, E||Mondrik, N||Marshall, JL||Yanny, B||Bechtol, K||Drlica-Wagner, A||Oscar, D||Santiago, B||Simon, JD||Vivas, AK||Walker, AR||Wang, MY||Abbott, TMC||Abdalla, FB||Benorr-Levy, A||Bernstein, GM||Bertin, E||Brooks, D||Burke, DL||Carnero Rosell, A||Kind, M Carrasco||Carretero, J||da Costa, LN||DePoy, DL||Desai, S||Diehl, HT||Doel, P||Estrada, J||Finley, DA||Flaugher, B||Frieman, J||Gruen, D||Gruendl, RA||Gutierrez, G||Honscheid, K||James, DJ||Kuehn, K||Kuropatkin, N||Lahav, O||Maia, MAG||March, M||Martini, P||Ogando, R||Plazas, AA||Reil, K||Romer, AK||Roodman, A||Sanchez, E||Scarpine, V||Schubnell, M||Sevilla-Noarbe, I||Smith, RC||Soares-Santos, M||Sobreira, F||Suchyta, E||Swanson, MEC||Tarle, G||Tucker, D||Zhang, Y

publication date

  • February 2016