SPECTROSCOPIC CONFIRMATION OF THE PISCES OVERDENSITY

Journal Article · Tue Nov 10 00:00:00 EST 2009 · Astrophysical Journal (Online)

DOI:https://doi.org/10.1088/0004-637X/705/2/L158· OSTI ID:21378292

Kollmeier, Juna A; Shectman, Stephen; Thompson, Ian B; Preston, George W; Simon, Joshua D; Crane, Jeffrey D ^[1]; Gould, Andrew ^[2]; Ivezic, Zeljko; Sesar, Branimir ^[3]

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1. Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
2. Department of Astronomy, Ohio State University, 4051 McPherson Laboratory, Columbus, OH 43210 (United States)
3. Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195-1580 (United States)

We present spectroscopic confirmation of the 'Pisces Overdensity', also known as 'Structure J', a photometric overdensity of RR Lyrae stars discovered by the Sloan Digital Sky Survey at an estimated photometric distance of approx85 kpc. We measure radial velocities for eight RR Lyrae stars within Pisces. We find that five of the eight stars have heliocentric radial velocities within a narrow range of -87 km s{sup -1} < v{sub r} < -67 km s{sup -1}, suggesting that the photometric overdensity is mainly due to a physically associated system, probably a dwarf galaxy or a disrupted galaxy. Two of the remaining three stars differ from one another by only 9 km s{sup -1}, but it would be premature to identify them as a second system.

• OSTI ID: 21378292
• Journal Information: Astrophysical Journal (Online), Vol. 705, Issue 2; Other Information: DOI: 10.1088/0004-637X/705/2/L158; ISSN 1538-4357
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
DISTANCE
GALAXIES
RADIAL VELOCITY
SKY
STARS
VELOCITY