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Discovery of a stellar overdensity in Eridanus-Phoenix in the Dark Energy Survey

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posted on 2023-06-09, 01:52 authored by T S Li, E Balbinot, N Mondrik, J L Marshall, B Yanny, K Bechtol, A Drlica-Wagner, D Oscar, B Santiago, J D Simon, A K Vivas, A R Walker, M Y Wang, T M C Abbott, F B Abdalla, A Benoit-Lévy, G M Bernstein, E Bertin, D Brooks, D L Burke, A Carnero Rosell, M Carrasco Kind, J Carretero, L N da Costa, D L DePoy, S Desai, H T Diehl, P Doel, J Estrada, D A Finley, B Flaugher, J Frieman, D Gruen, R A Gruendl, G Gutierrez, K Honscheid, D J James, K Kuehn, N Kuropatkin, O Lahav, M A G Maia, M March, P Martini, R Ogando, A A Plazas, K Reil, Kathy RomerKathy Romer, A Roodman, E Sanchez, V Scarpine, M Schubnell, I Sevilla-Noarbe, R C Smith, M Soares-Santos, F Sobreira, E Suchyta, M E C Swanson, G Tarle, D Tucker, Y Zhang
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 Eridanus-Phoenix (EriPhe) overdensity is centered around l˜ 285^\circ and b˜ -60^\circ and spans at least 30° in longitude and 10° in latitude. The Poisson significance of the detection is at least 9sigma . 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 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 Hercules-Aquila 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.

Funding

Astrophysics and Cosmology - Sussex Consolidated Grant; G1291; STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL; ST/L000652/1

History

Publication status

  • Published

File Version

  • Published version

Journal

The Astrophysical Journal

ISSN

1538-4357

Publisher

American Astronomical Society

Issue

2

Volume

817

Page range

135

Department affiliated with

  • Physics and Astronomy Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2016-06-24

First Open Access (FOA) Date

2016-06-24

First Compliant Deposit (FCD) Date

2016-06-23

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