A REFINED QSO SELECTION METHOD USING DIAGNOSTICS TESTS: 663 QSO CANDIDATES IN THE LARGE MAGELLANIC CLOUD

We present 663 QSO candidates in the Large Magellanic Cloud (LMC) selected using multiple diagnostics. We started with a set of 2566 QSO candidates selected using the methodology presented in our previous work based on time variability of the MACHO LMC light curves. We then obtained additional information for the candidates by crossmatching them with the Spitzer SAGE, the Two Micron All Sky Survey, the Chandra, the XMM, and an LMC UBVI catalog. Using this information, we specified six diagnostic features based on mid-IR colors, photometric redshifts using spectral energy distribution template fitting, and X-ray luminosities in order to further discriminate high-confidence QSO candidates in the absence of spectra information. We then trained a one-class Support Vector Machine model using the diagnostics features of the confirmed 58 MACHO QSOs. We applied the trained model to the original candidates and finally selected 663 high-confidence QSO candidates. Furthermore, we crossmatched these 663 QSO candidates with the newly confirmed 151 QSOs and 275 non-QSOs in the LMC fields. On the basis of the counterpart analysis, we found that the false positive rate is less than 1%.

[1]  Pavlos Protopapas,et al.  QUASI-STELLAR OBJECT SELECTION ALGORITHM USING TIME VARIABILITY AND MACHINE LEARNING: SELECTION OF 1620 QUASI-STELLAR OBJECT CANDIDATES FROM MACHO LARGE MAGELLANIC CLOUD DATABASE , 2011 .

[2]  Richard G. McMahon,et al.  The variability of optically selected quasars , 1994 .

[3]  Oxford,et al.  Breaking the hierarchy of galaxy formation , 2005, astro-ph/0511338.

[4]  Jonathan C. McDowell,et al.  THE CHANDRA SOURCE CATALOG , 2009, 1005.4665.

[5]  Duncan Farrah,et al.  Photometric redshifts in the SWIRE Survey , 2008, 0802.1890.

[6]  Linda J. Smith,et al.  SPITZER SURVEY OF THE LARGE MAGELLANIC CLOUD, SURVEYING THE AGENTS OF A GALAXY'S EVOLUTION (SAGE). IV. DUST PROPERTIES IN THE INTERSTELLAR MEDIUM , 2005, Proceedings of the International Astronomical Union.

[7]  Eduardo Gonzalez-Solares,et al.  Spectral Energy Distributions and Luminosities of Galaxies and Active Galactic Nuclei in the Spitzer Wide-Area Infrared Extragalactic (SWIRE) Legacy Survey , 2005 .

[8]  P H Ellaway,et al.  Cumulative sum technique and its application to the analysis of peristimulus time histograms. , 1978, Electroencephalography and clinical neurophysiology.

[9]  R. Della Ceca,et al.  2-10 KeV luminosity of high - mass binaries as a gauge of ongoing star - formation rate , 2004 .

[10]  Kristin P. Bennett,et al.  Support vector machines: hype or hallelujah? , 2000, SKDD.

[11]  Usa,et al.  QUANTIFYING QUASAR VARIABILITY AS PART OF A GENERAL APPROACH TO CLASSIFYING CONTINUOUSLY VARYING SOURCES , 2009, 0909.1326.

[12]  Chih-Jen Lin,et al.  A Practical Guide to Support Vector Classication , 2008 .

[13]  A. Macciò,et al.  Constraining warm dark matter using QSO gravitational lensing , 2007, 0706.0896.

[14]  Brandon C. Kelly,et al.  Are the Variations in Quasar Optical Flux Driven by Thermal Fluctuations , 2009 .

[15]  G. Wilson,et al.  Obscured and unobscured active galactic nuclei in the Spitzer Space Telescope First Look Survey , 2004 .

[16]  Nello Cristianini,et al.  An introduction to Support Vector Machines , 2000 .

[17]  E. L. Wright,et al.  The Infrared Array Camera (IRAC) Shallow Survey , 2004 .

[18]  E. Bullock,et al.  MODELING THE TIME VARIABILITY OF SDSS STRIPE 82 QUASARS AS A DAMPED RANDOM WALK , 2010, 1004.0276.

[19]  A. Connolly,et al.  CLUSTERING OF LOW-REDSHIFT (z ⩽ 2.2) QUASARS FROM THE SLOAN DIGITAL SKY SURVEY , 2008, 0903.3230.

[20]  A. Georgakakis,et al.  Testing the starburst/AGN connection with SWIRE X‐ray/70 μm sources , 2009, 0906.4938.

[21]  Arjun Dey,et al.  Submitted to the Astrophysical Journal Letters Mid-Infrared Selection of Active Galaxies , 2004 .

[22]  J. Brinchmann,et al.  Present-Day Growth of Black Holes and Bulges: The Sloan Digital Sky Survey Perspective , 2004, astro-ph/0406218.

[23]  C. Kochanek,et al.  THE MAGELLANIC QUASARS SURVEY. II. CONFIRMATION OF 144 NEW ACTIVE GALACTIC NUCLEI BEHIND THE SOUTHERN EDGE OF THE LARGE MAGELLANIC CLOUD , 2011, 1106.3110.

[24]  I. M. Stewart,et al.  The XMM-Newton serendipitous survey. V. The Second XMM-Newton serendipitous source catalogue , 2008, 0807.1067.

[25]  Malik Yousef,et al.  One-Class SVMs for Document Classification , 2002, J. Mach. Learn. Res..

[26]  Eva K. Grebel,et al.  The Magellanic Clouds Photometric Survey: The Large Magellanic Cloud Stellar Catalog and Extinction Map , 2004 .

[27]  Vladimir Churilov,et al.  Performance of AAOmega: the AAT multi-purpose fiber-fed spectrograph , 2006, SPIE Astronomical Telescopes + Instrumentation.

[28]  Discovery of nine quasars behind the Large Magellanic Cloud , 2005, astro-ph/0507200.

[29]  Nick Kaiser,et al.  Pan-STARRS: a wide-field optical survey telescope array , 2004, SPIE Astronomical Telescopes + Instrumentation.

[30]  M. S. Oey,et al.  Atlas of quasar energy distributions , 1994 .

[31]  S. Mineshige,et al.  Optical Variability in Active Galactic Nuclei: Starbursts or Disk Instabilities? , 1997, astro-ph/9712006.

[32]  Chih-Jen Lin,et al.  LIBSVM: A library for support vector machines , 2011, TIST.

[33]  M. Skrutskie,et al.  The Two Micron All Sky Survey (2MASS) , 2006 .

[34]  A. Udalski,et al.  The Optical Gravitational Lensing Experiment. Final Reductions of the OGLE-III Data , 2008, 0807.3884.

[35]  C. Kochanek,et al.  DISCOVERY OF 5000 ACTIVE GALACTIC NUCLEI BEHIND THE MAGELLANIC CLOUDS , 2009, 0904.1740.

[36]  Arjun Dey,et al.  Black Hole Masses and Eddington Ratios at 0.3 < z < 4 , 2005, astro-ph/0508657.

[37]  Variability in active galactic nuclei: confrontation of models with observations , 2001, astro-ph/0110707.

[38]  Bernhard Schölkopf,et al.  Estimating the Support of a High-Dimensional Distribution , 2001, Neural Computation.

[39]  P. Davoodi,et al.  Spectral energy distributions and luminosities of galaxies and AGN in the SPITZER SWIRE Legacy Survey , 2004 .

[40]  A. J. Drake,et al.  Variability-selected Quasars in MACHO Project Magellanic Cloud Fields , 2002, astro-ph/0209513.

[41]  M. Rees.  BLACK HOLE MODELS FOR ACTIVE GALACTIC NUCLEI , 1984 .