Discovery of a Group of Receding, Variable Halo Stars toward Norma
- School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623 (United States)
- Departamento de Fisica y Astronomia, Universidad de La Serena, Av. Juan Cisternas 1200 N, La Serena (Chile)
- Research School of Astronomy and Astrophysics ANU RSAA Mount Stromlo Observatory (Australia)
- The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
- Warsaw University Observatory, al. Ujazdowskie 4, 00-001 Warszawa (Poland)
- Universidad de Concepcion, Concepción, Bío Bío Region (Chile)
- Max-Planck Institute for Astronomy, Room 332, Könighstuhl 17, D-69117 Heidelberg (Germany)
- Department of Astronomy, Campbell Hall, #501, Berkeley, CA 94720 (United States)
- SOFIA-USRA, NASA Ames Research Center, Mail Stop N232-12, Moffet Field, CA 94035-1000 (United States)
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50010 (United States)
- Department of Astronomy, UC Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States)
- Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States)
- Dept of Physics, PO Box 413, Milwaukee, WI 53201 (United States)
We present results from spectroscopic observations of a trio of Cepheid candidates identified from K {sub s} -band light curves toward Norma. The spectra show that these stars are moving with a large and similar radial velocity—the heliocentric velocities are 171 ± 32 km s{sup −1}, 164 ± 37 km s{sup −1}, and 173 ± 20 km s{sup −1}. The average radial velocity is ∼169 km s{sup −1}, which is large and distinct from typical stars in the Galaxy’s stellar disk. Given the radial velocities and associated 1 σ error, we find that the combined probability that these three stars are foreground Milky Way disk stars is ∼7 × 10{sup −4}%, and the probability that these are large-amplitude spotted stars in a binary is ∼10{sup −5}%. These objects at l ∼ 333° and b ∼ −1° are therefore associated with the stellar halo. The identification of these sources as Type I Cepheids is not certain, and thus the distances of these sources are not yet well established. Assuming the 3.6 μ m period–luminosity relation of Type I Cepheids gives a distance of ∼78 kpc for these sources.
- OSTI ID:
- 22663310
- Journal Information:
- Astrophysical Journal, Vol. 844, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
THE DISCOVERY OF A MOLECULAR CAVITY IN THE NORMA NEAR ARM ASSOCIATED WITH H.E.S.S {gamma}-RAY SOURCE LOCATED IN THE DIRECTION OF WESTERLUND 1
Spectroscopic Observations of Obscured Populations in the Inner Galaxy: 2MASS-GC02, Terzan 4, and the 200 km s{sup −1} stellar peak