skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Discovery of a stellar overdensity in Eridanus-Phoenix in the dark energy survey

Journal Article · · The Astrophysical Journal (Online)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less

Here, we report the discovery of an excess of main sequence turn-off 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° and b~-60° and spans at least 30° in longitude and 10 deg in latitude. The Poisson significance of the detection is at least 9 sigma. 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.

Research Organization:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), High Energy Physics (HEP)
Contributing Organization:
The DES Collaboration
Grant/Contract Number:
AC02-07CH11359; AC02-76SF00515
OSTI ID:
1234896
Alternate ID(s):
OSTI ID: 1257727
Report Number(s):
FERMILAB-PUB-15-392-AE; SLAC-PUB-16571; arXiv eprint number arXiv:1509.04296
Journal Information:
The Astrophysical Journal (Online), Vol. 817, Issue 2; ISSN 1538-4357
Publisher:
Institute of Physics (IOP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 26 works
Citation information provided by
Web of Science

References (81)

Astropy: A community Python package for astronomy journal September 2013
A new Milky way halo star Cluster in the Southern Galactic sky journal April 2013
The LMC geometry and outer stellar populations from early DES data journal March 2015
Eight new Milky way Companions Discovered in First-Year dark Energy Survey data journal June 2015
The Hercules-Aquila Cloud journal February 2007
A Faint New Milky Way Satellite in Bootes journal August 2006
The Field of Streams: Sagittarius and Its Siblings journal April 2006
SExtractor: Software for source extraction journal June 1996
Update on the Nature of Virgo Overdensity journal March 2012
galpy: A python LIBRARY FOR GALACTIC DYNAMICS journal February 2015
Tracing Galaxy Formation with Stellar Halos. I. Methods journal December 2005
A search for stellar tidal debris of defunct dwarf galaxies around globular clusters in the inner Galactic halo journal October 2014
The Origin of the Virgo Stellar Substructure journal June 2012
The 10 Meter South Pole Telescope
  • Carlstrom, J. E.; Ade, P. A. R.; Aird, K. A.
  • Publications of the Astronomical Society of the Pacific, Vol. 123, Issue 903 https://doi.org/10.1086/659879
journal May 2011
Galactic stellar haloes in the CDM model: Galactic stellar haloes in the CDM model journal May 2010
Exploring Halo Substructure with Giant Stars: Spectroscopy of Stars in the Galactic Anticenter Stellar Structure journal August 2003
Absolute proper motions of globular clusters journal April 2006
The Blanco Cosmology Survey: data Acquisition, Processing, Calibration, Quality Diagnostics, and data Release journal September 2012
The Dark Energy Survey and operations: Year 1 conference August 2014
The Dartmouth Stellar Evolution Database journal September 2008
A comprehensive view of the Virgo stellar stream journal June 2014
Spectroscopy of QUEST RR Lyrae Variables: The New Virgo Stellar Stream journal December 2005
Evidence from the motions of old stars that the Galaxy collapsed. journal September 1962
Correcting for the Effects of Interstellar Extinction journal January 1999
Cosmological simulations of the formation of the stellar haloes around disc galaxies: Stellar haloes of disc galaxies journal July 2011
Accreted versus in situ Milky Way globular clusters journal February 2010
A Catalog of Parameters for Globular Clusters in the Milky Way journal October 1996
The Structural Evolution of Substructure journal February 2003
Substructure in the Stellar Halos of the Aquarius Simulations journal April 2011
Galactic Stellar Populations in the Era of the Sloan Digital Sky Survey and Other Large Surveys journal September 2012
Tracing Galaxy Formation with Stellar Halos. II. Relating Substructure in Phase and Abundance Space to Accretion Histories journal December 2008
Probing the halo from the Solar Vicinity to the Outer Galaxy: Connecting Stars in Local Velocity Structures to Large-Scale Clouds journal November 2012
The Milky Way Tomography with SDSS. I. Stellar Number Density Distribution journal February 2008
Horologium ii: a Second Ultra-Faint Milky way Satellite in the Horologium Constellation journal July 2015
A Hero’S dark Horse: Discovery of an Ultra-Faint Milky way Satellite in Pegasus journal May 2015
Spectroscopic Confirmation of the Pisces Overdensity journal October 2009
The Discovery of Two Extremely Low Luminosity Milky Way Globular Clusters journal November 2007
Beasts of the Southern Wild: Discovery of nine Ultra Faint Satellites in the Vicinity of the Magellanic Clouds journal May 2015
SAGITTARIUS II, DRACO II AND LAEVENS 3: THREE NEW MILKY WAY SATELLITES DISCOVERED IN THE PAN-STARRS 1 3 π SURVEY journal October 2015
The distribution of satellite galaxies: the great pancake journal October 2005
A Two Micron All Sky Survey View of the Sagittarius Dwarf Galaxy. I. Morphology of the Sagittarius Core and Tidal Arms journal December 2003
The acs Survey of Galactic Globular Clusters. vii. Relative ages journal March 2009
A dwarf galaxy remnant in Canis Major: the fossil of an in-plane accretion on to the Milky Way journal February 2004
Hydra ii: a Faint and Compact Milky way Dwarf Galaxy Found in the Survey of the Magellanic Stellar History journal April 2015
Tracing Out the Northern Tidal Stream of the Sagittarius Dwarf Spheroidal Galaxy
  • Martinez‐Delgado, David; Gomez‐Flechoso, M. Angeles; Aparicio, Antonio
  • The Astrophysical Journal, Vol. 601, Issue 1 https://doi.org/10.1086/380298
journal January 2004
Dwarf Galaxies of the Local Group journal September 1998
The Observed Properties of Dwarf Galaxies in and Around the Local Group journal June 2012
The Dark Energy Survey data processing and calibration system conference September 2012
The Orbit of the Orphan Stream journal February 2010
The Ghost of Sagittarius and Lumps in the Halo of the Milky Way journal April 2002
Detection of Massive Tidal Tails around the Globular Cluster Palomar 5 with Sloan Digital Sky Survey Commissioning Data journal February 2001
The VPOS: a vast polar structure of satellite galaxies, globular clusters and streams around the Milky Way: The VPOS: a vast polar structure around the MW journal May 2012
A Comprehensive Model for the Monoceros Tidal Stream journal June 2005
A reinterpretation of the Triangulum–Andromeda stellar clouds: a population of halo stars kicked out of the Galactic disc journal July 2015
Exploring Halo Substructure with Giant Stars: A Diffuse Star Cloud or Tidal Debris around the Milky Way in Triangulum‐Andromeda journal November 2004
The dark Energy Survey: Prospects for Resolved Stellar Populations journal May 2011
An analytical phase-space model for tidal caustics journal August 2013
Measuring Reddening with Sloan Digital sky Survey Stellar Spectra and Recalibrating sfd journal August 2011
Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds journal June 1998
Compositions of halo clusters and the formation of the galactic halo journal October 1978
Exploring the Variable Sky with the Sloan Digital Sky Survey journal October 2007
Halo Velocity Groups in the Pisces Overdensity journal June 2010
Galaxia: a code to Generate a Synthetic Survey of the Milky way journal February 2011
Group Finding in the Stellar halo Using M-Giants in the two Micron all sky Survey: an Extended view of the Pisces Overdensity? journal September 2010
Strong RR Lyrae excess in the Hercules-Aquila Cloud journal March 2014
The Two Micron All Sky Survey (2MASS) journal February 2006
The Complex Structure of Stars in the Outer Galactic disk as Revealed by Pan-Starrs1 journal July 2014
A deep view of the Monoceros ring in the Anticenter Direction: Clues of its Extra-Galactic Origin journal February 2011
The hierarchical origin of galaxy morphologies journal June 2002
The QUEST RR Lyrae Survey: Confirmation of the Clump at 50 Kiloparsecs and Other Overdensities in the Outer Halo journal June 2001
A Pair of Boötes: A New Milky Way Satellite journal May 2007
The spatial distribution of galactic satellites in the Λ cold dark matter cosmology journal December 2012
Substructure revealed by RR Lyraes in SDSS Stripe 82 journal October 2009
Galaxy formation through hierarchical clustering journal September 1991
A New Milky Way Companion: Unusual Globular Cluster or Extreme Dwarf Satellite? journal June 2005
A New Milky Way Dwarf Galaxy in Ursa Major journal May 2005
Rings and Radial Waves in the disk of the Milky way journal March 2015
A Low‐Latitude Halo Stream around the Milky Way journal May 2003
The Sloan Digital Sky Survey: Technical Summary journal September 2000
The Physics of Galaxy Clustering. I. A Model for Subhalo Populations journal May 2005
A New Milky Way Dwarf Satellite in Canes Venatici journal May 2006

Cited By (16)

The outer envelopes of globular clusters. II. NGC 1851, NGC 5824 and NGC 1261* journal September 2017
Tails and streams around the Galactic globular clusters NGC 1851, NGC 1904, NGC 2298 and NGC 2808 journal October 2017
Common origin for Hercules-Aquila and Virgo Clouds in Gaia DR2 journal October 2018
Disentangling the Virgo Overdensity with rr Lyrae Stars journal November 2016
Identification of RR Lyrae Stars in Multiband, Sparsely Sampled Data from the Dark Energy Survey Using Template Fitting and Random Forest Classification journal June 2019
Stellar Streams Discovered in the Dark Energy Survey journal July 2018
Proper Motions of Stellar Streams Discovered in the Dark Energy Survey journal October 2019
Triangulum–Andromeda Overdensity: a Region with a Complex Stellar Population journal November 2019
The Virgo Overdensity Explained journal November 2019
Fitting the Density Substructure of the Stellar Halo with MilkyWay@home journal September 2018
Disentangling the Virgo Overdensity with RR Lyrae stars text January 2016
The Outer Envelopes of Globular Clusters. II. NGC 1851, NGC 5824 and NGC 1261 text January 2017
Common origin for Hercules-Aquila and Virgo Clouds in Gaia DR2 text January 2018
Fitting the density substructure of the stellar halo with MilkyWay@home text January 2018
Identification of RR Lyrae stars in multiband, sparsely-sampled data from the Dark Energy Survey using template fitting and Random Forest classification text January 2019
Triangulum-Andromeda overdensity: a region with a complex stellar population text January 2019

Similar Records

Discovery of a stellar overdensity in Eridanus–Phoenix in the Dark Energy Survey
Journal Article · Mon Feb 01 00:00:00 EST 2016 · Astrophysical Journal · OSTI ID:1234896
+17 more
Exploring Milkyway Halo Substructures with Large-Area Sky Surveys
Thesis/Dissertation · Fri Jan 01 00:00:00 EST 2016 · OSTI ID:1234896
The Phoenix stream: A cold stream in the southern hemisphere
Journal Article · Thu Mar 17 00:00:00 EDT 2016 · The Astrophysical Journal (Online) · OSTI ID:1234896

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
Astrophysics
galaxy: formation
galaxy: halo
galaxy: structure
galaxy: local group