Discovery of nine quasars behind the Large Magellanic Cloud

被引:15
作者
Dobrzycki, A
Eyer, L
Stanek, KZ
Macri, LM
机构
[1] European So Observ, D-85748 Garching, Germany
[2] Observ Geneva, CH-1290 Sauverny, Switzerland
[3] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA
[4] Ohio State Univ, Dept Astron, Columbus, OH 43210 USA
[5] Natl Opt Astron Observ, Tucson, AZ 85719 USA
关键词
Magellanic Clouds; quasars : general;
D O I
10.1051/0004-6361:20053494
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present the discovery of nine quasars behind the Large Magellanic Cloud, with emission redshifts ranging from 0.07 to 2.09. Six of them were identified as part of the systematic variability-based search for QSOs in the objects from the OGLE-II database. Combination of variability-based selection of candidates with the candidates' colours appears to be a powerful technique for identifying quasars, potentially reaching similar to 50% efficiency. We report an apparent correlation between variability magnitude and variability timescale, which - if confirmed could put even more constraints on QSO candidate selection. The remaining three quasars were identified via followup spectroscopy of optical counterparts to X-ray sources found serendipitously by the Chandra X-ray Observatory satellite. Even though the locations of the candidates were quite uniformly distributed over the LMC bar, the confirmed QSOs all appear near the bar's outskirts.
引用
收藏
页码:495 / 500
页数:6
相关论文
共 20 条
[1]   Proper motion of the Large Magellanic Cloud using QSOs as an inertial reference system [J].
Anguita, C ;
Loyola, P ;
Pedreros, MH .
ASTRONOMICAL JOURNAL, 2000, 120 (02) :845-854
[2]   The ensemble photometric variability of ∼25,000 quasars in the Sloan Digital Sky Survey [J].
Berk, DEV ;
Wilhite, BC ;
Kron, RG ;
Anderson, SF ;
Brunner, RJ ;
Hall, PB ;
Ivezic, Z ;
Richards, GT ;
Schneider, DP ;
York, DG ;
Brinkmann, JV ;
Lamb, DQ ;
Nichol, RC ;
Schlegel, DJ .
ASTROPHYSICAL JOURNAL, 2004, 601 (02) :692-714
[3]  
CRISTIANI S, 1989, ASTRON ASTROPHYS SUP, V77, P161
[4]   New X-ray quasars behind the Small Magellanic Cloud [J].
Dobrzycki, A ;
Stanek, KZ ;
Macri, LM ;
Groot, PJ .
ASTRONOMICAL JOURNAL, 2003, 126 (02) :734-741
[5]   Variability-selected quasars behind the Small Magellanic Cloud [J].
Dobrzycki, A ;
Macri, LM ;
Stanek, KZ ;
Groot, PJ .
ASTRONOMICAL JOURNAL, 2003, 125 (03) :1330-1335
[6]   Discovery of four X-ray quasars behind the Large Magellanic Cloud [J].
Dobrzycki, A ;
Groot, PJ ;
Macri, LM ;
Stanek, KZ .
ASTROPHYSICAL JOURNAL, 2002, 569 (01) :L15-L18
[7]   Direct extragalactic distance determination using X-ray scattering [J].
Draine, BT ;
Bond, NA .
ASTROPHYSICAL JOURNAL, 2004, 617 (02) :987-1003
[8]  
Eyer L, 2002, ACTA ASTRONOM, V52, P241
[9]   Variability-selected quasars in MACHO project Magellanic Cloud fields [J].
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 .
ASTRONOMICAL JOURNAL, 2003, 125 (01) :1-12
[10]   SOUTHERN SPECTROPHOTOMETRIC STANDARDS .1. [J].
HAMUY, M ;
WALKER, AR ;
SUNTZEFF, NB ;
GIGOUX, P ;
HEATHCOTE, SR ;
PHILLIPS, MM .
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC, 1992, 104 (677) :533-552