Variability-selected quasars in MACHO project Magellanic Cloud fields

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; et. al.

Abstract

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 ? 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 yr MACHO V- and R-band light curves with average sampling times of 2-10 days.

Más información

Título según WOS: Variability-selected quasars in MACHO project Magellanic Cloud fields
Título según SCOPUS: Variability-selected quasars in MACHO project magellanic cloud fields
Título de la Revista: ASTRONOMICAL JOURNAL
Volumen: 125
Número: 1
Editorial: IOP PUBLISHING LTD
Fecha de publicación: 2003
Página de inicio: 1
Página final: 12
Idioma: English
URL: http://stacks.iop.org/1538-3881/125/i=1/a=1
DOI:

10.1086/344947

Notas: ISI, SCOPUS