2007/12/05 by Ronald Wilhelm, Wilhelm, Ronald, W. Lee Powell +24
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.0712.0776
59 pages, 17 figures, 8 tables
arxiv created 2007/12/05 · openalex publication_date 2007/12/05 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We describe a new RR Lyrae identification technique based on out-of-phase single-epoch photometric and spectroscopic observations contained in SDSS Data Release 6 (DR-6). This technique detects variability by exploiting the large disparity between the g-r color and the strength of the hydrogen Balmer lines when the two observations are made at random phases. Comparison with a large sample of known variables in the SDSS equatorial stripe (Stripe 82) shows that the discovery efficiency for our technique is ~85%. Analysis of stars with multiple spectroscopic observations suggests a similar efficiency throughout the entire DR-6 sample. We also develop a technique to estimate the average g apparent magnitude (over the pulsation cycle) for individual RR Lyrae stars, using the <g-r> for the entire sample and measured colors for each star. The resulting distances are found to have precisions of ~14%. Finally, we explore the properties of our DR-6 sample of N = 1087 variables, and recover portions of the Sagittarius Northern and Southern Stream. Analysis of the distance and velocity for the Southern Stream are consistent with previously published data for blue horizontal-branch stars. In a sample near the North Galactic Polar Cap, we find evidence for the descending leading Northern arm, and a possible detection of the trailing arm.