Variability-selected quasars in MACHO project Magellanic Cloud fields

被引:88
作者
Geha, M
Alcock, C
Allsman, RA
Alves, DR
Axelrod, TS
Becker, AC
Bennett, DP
Cook, KH
Drake, AJ
Freeman, KC
Griest, K
Keller, SC
Lehner, MJ
Marshall, SL
Minniti, D
Nelson, CA
Peterson, BA
Popowski, P
Pratt, MR
Quinn, PJ
Stubbs, CW
Sutherland, W
Tomaney, AB
Vandehei, T
Welch, DL
机构
[1] Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA
[2] Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA
[3] Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA
[4] Natl Opt Astron Observ, Tucson, AZ 85719 USA
[5] Columbia Univ, Astrophys Lab, New York, NY 10027 USA
[6] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA
[7] Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA
[8] Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA
[9] Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile
[10] Mt Stromlo & Siding Spring Observ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia
[11] Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA
[12] Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA
[13] Max Planck Inst Astrophys, D-85748 Garching, Germany
[14] Univ Washington, Dept Astron, Seattle, WA 98195 USA
[15] Univ Washington, Dept Phys, Seattle, WA 98195 USA
[16] European So Observ, D-85748 Garching, Germany
[17] Univ Oxford, Oxford OX1 3RH, England
[18] McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada
关键词
Magellanic Clouds; quasars : general;
D O I
10.1086/344947
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
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 have apparent mean magnitudes 16.6 less than or equal to (V) over bar less than or equal to 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 yr MACHO V- and R-band light curves with average sampling times of 2 10 days.
引用
收藏
页码:1 / 12
页数:12
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