NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-05-25 T08:50:46 PDT
Help | Comment | NED Home

For refcode 2016ApJ...817...73H:
Retrieve 34 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
2016ApJ...817...73H Finding, Characterizing, and Classifying Variable Sources in Multi-epoch Sky Surveys: QSOs and RR Lyrae in PS1 3pi data Hernitschek, Nina; Schlafly, Edward F.; Sesar, Branimir; Rix, Hans-Walter; Hogg, David W.; Ivezic, Zeljko; Grebel, Eva K.; Bell, Eric F.; Martin, Nicolas F.; Burgett, W. S.; Flewelling, H.; Hodapp, K. W.; Kaiser, N.; Magnier, E. A.; Metcalfe, N.; Wainscoat, R. J.; Waters, C. Abstract. In area and depth, the Pan-STARRS1 (PS1) 3pi survey is unique among many-epoch, multi-band surveys and has enormous potential for the all-sky identification of variable sources. PS1 has observed the sky typically seven times in each of its five bands (grizy) over 3.5 years, but unlike SDSS, not simultaneously across the bands. Here we develop a new approach for quantifying statistical properties of non-simultaneous, sparse, multi-color light curves through light curve structure functions, effectively turning PS1 into a ~35-epoch survey. We use this approach to estimate variability amplitudes and timescales (omega_r_, tau) for all point sources brighter than r_P1_ = 21.5 mag in the survey. With PS1 data on SDSS Stripe 82 as "ground truth," we use a Random Forest Classifier to identify QSOs and RR Lyrae based on their variability and their mean PS1 and WISE colors. We find that, aside from the Galactic plane, QSO and RR Lyrae samples of purity ~75% and completeness ~92% can be selected. On this basis we have identified a sample of ~1,000,000 QSO candidates, as well as an unprecedentedly large and deep sample of ~150,000 RR Lyrae candidates with distances from ~10 to ~120 kpc. Within the Draco dwarf spheroidal, we demonstrate a distance precision of 6% for RR Lyrae candidates. We provide a catalog of all likely variable point sources and likely QSOs in PS1, a total of 25.8 x 10^6^ sources. Key words: methods: statistical, quasars: general, stars: variables: RR Lyrae
Retrieve 34 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home