Variability-Selected Quasars in MACHO Project Magellanic Cloud Fields

• Main Authors: Geha, M, Alcock, C, Allsman, R. A, Alves, D. R, Axelrod, T. S, Becker, A. C, Bennett, D. P, Cook, K. H, Drake, A. J, Freeman, K. C, Griest, K, Keller, S. C, Lehner, M. J, Marshall, S. L, Minniti, D, Nelson, C. A, Peterson, B. A, Popowski, P, Pratt, M. R, Quinn, P. J, Stubbs, C. W, Sutherland, W, Tomaney, A. B, Vandehei, T, Welch, D. L
• Format: Journal Article
• Language: English
• Published: 24-09-2002
• Subjects: Physics - Astrophysics of Galaxies; Physics - Cosmology and Nongalactic Astrophysics; Physics - Earth and Planetary Astrophysics; Physics - High Energy Astrophysical Phenomena; Physics - Instrumentation and Methods for Astrophysics; Physics - Solar and Stellar Astrophysics
• DOI: 10.48550/arxiv.astro-ph/0209513

Astron.J. 125 (2003) 1 We present 47 spectroscopically-confirmed quasars discovered behind the
Magellanic Clouds identified via photometric variability in the MACHO database.
Thirty-eight quasars lie behind the Large Magellanic Cloud and nine behind the
Small Magellanic Cloud, more than tripling the number of quasars previously
known in this region. The quasars cover the redshift interval 0.2 < z < 2.8 and
apparent mean magnitudes 16.6 < V < 20.1. We discuss the details of quasar
candidate selection based on time variability in the MACHO database and present
results of spectroscopic follow-up observations. Our follow-up detection
efficiency was 20%; the primary contaminants were emission-line Be stars in
Magellanic Clouds. For the 47 quasars discovered behind the Magellanic Clouds
plus an additional 12 objects previously identified in this region, we present
7.5-year MACHO V- and R-band lightcurves with average sampling times of 2-10
days.