Variability-selected quasars in MACHO project magellanic cloud fields

M. Geha; C. Alcock; R. A. Allsman; D. R. Alves; T. S. Axelrod; A. C. Becker; D. P. Bennett; K. H. Cook; A. J. Drake; K. C. Freeman; K. Griest; S. C. Keller; M. J. Lehner; S. L. Marshall; D. Minniti; C. A. Nelson; B. A. Peterson; P. Popowski; M. R. Pratt; P. J. Quinn; C. W. Stubbs; W. Sutherland; A. B. Tomaney; T. Vandehei; D. L. Welch

doi:10.1086/344947

Variability-selected quasars in MACHO project magellanic cloud fields

M. Geha^*, C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A. C. Becker, D. P. Bennett, K. H. Cook, A. J. Drake, K. C. Freeman, K. Griest, S. C. Keller, M. J. Lehner, S. L. Marshall, D. Minniti, C. A. Nelson, B. A. Peterson, P. Popowski, M. R. Pratt, P. J. QuinnC. W. Stubbs, W. Sutherland, A. B. Tomaney, T. Vandehei, D. L. Welch

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

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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 ≤ V̄ ≤ 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.

Original language	English
Pages (from-to)	1-12
Number of pages	12
Journal	Astronomical Journal
Volume	125
Issue number	1 1765
DOIs	https://doi.org/10.1086/344947
Publication status	Published - Jan 2003

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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., ... Welch, D. L. (2003). Variability-selected quasars in MACHO project magellanic cloud fields. Astronomical Journal, 125(1 1765), 1-12. https://doi.org/10.1086/344947

@article{3bfecb807fdb43a8a2b602e49c1c04e4,

title = "Variability-selected quasars in MACHO project magellanic cloud fields",

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.",

keywords = "Magellanic Clouds, Quasars: general",

author = "M. Geha and C. Alcock and Allsman, {R. A.} and Alves, {D. R.} and Axelrod, {T. S.} and Becker, {A. C.} and Bennett, {D. P.} and Cook, {K. H.} and Drake, {A. J.} and Freeman, {K. C.} and K. Griest and Keller, {S. C.} and Lehner, {M. J.} and Marshall, {S. L.} and D. Minniti and Nelson, {C. A.} and Peterson, {B. A.} and P. Popowski and Pratt, {M. R.} and Quinn, {P. J.} and Stubbs, {C. W.} and W. Sutherland and Tomaney, {A. B.} and T. Vandehei and Welch, {D. L.}",

year = "2003",

month = jan,

doi = "10.1086/344947",

language = "English",

volume = "125",

pages = "1--12",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "American Astronomical Society",

number = "1 1765",

}

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 2003, 'Variability-selected quasars in MACHO project magellanic cloud fields', Astronomical Journal, vol. 125, no. 1 1765, pp. 1-12. https://doi.org/10.1086/344947

TY - JOUR

T1 - Variability-selected quasars in MACHO project magellanic cloud fields

AU - Geha, M.

AU - Alcock, C.

AU - Allsman, R. A.

AU - Alves, D. R.

AU - Axelrod, T. S.

AU - Becker, A. C.

AU - Bennett, D. P.

AU - Cook, K. H.

AU - Drake, A. J.

AU - Freeman, K. C.

AU - Griest, K.

AU - Keller, S. C.

AU - Lehner, M. J.

AU - Marshall, S. L.

AU - Minniti, D.

AU - Nelson, C. A.

AU - Peterson, B. A.

AU - Popowski, P.

AU - Pratt, M. R.

AU - Quinn, P. J.

AU - Stubbs, C. W.

AU - Sutherland, W.

AU - Tomaney, A. B.

AU - Vandehei, T.

AU - Welch, D. L.

PY - 2003/1

Y1 - 2003/1

N2 - 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 ≤ V̄ ≤ 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.

AB - 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 ≤ V̄ ≤ 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.

KW - Magellanic Clouds

KW - Quasars: general

UR - http://www.scopus.com/inward/record.url?scp=0041759997&partnerID=8YFLogxK

U2 - 10.1086/344947

DO - 10.1086/344947

M3 - Article

SN - 0004-6256

VL - 125

SP - 1

EP - 12

JO - Astronomical Journal

JF - Astronomical Journal

IS - 1 1765

ER -

Variability-selected quasars in MACHO project magellanic cloud fields

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