Discovery of a stellar overdensity in Eridanus–Phoenix in the Dark Energy Survey
- George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)
- Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)
- Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)
- Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States)
- Instituto de Física, UFRGS, Caixa Postal 15051, Porto Alegre, RS—91501-970 (Brazil)
- Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
- Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena (Chile)
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT (United Kingdom)
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States)
- CNRS, UMR 7095, Institut d’Astrophysique de Paris, F-75014, Paris (France)
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{sup ∘} and b∼−60{sup ∘} and spans at least 30° in longitude and 10° in latitude. The Poisson significance of the detection is at least 9σ. 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.
- OSTI ID:
- 22887103
- Journal Information:
- Astrophysical Journal, Vol. 817, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
- Country of Publication:
- United Kingdom
- Language:
- English
Similar Records
Exploring Milkyway Halo Substructures with Large-Area Sky Surveys
The Phoenix stream: A cold stream in the southern hemisphere