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The Time-Domain Spectroscopic Survey: Understanding the Optically Variable Sky with Sequels in SDSS-III
The Astrophysical Journal
  • John J. Ruan
  • Scott F. Anderson
  • Paul J. Green
  • Eric Morganson
  • Michael Eracleous
  • Adam D. Myers
  • Carles Badenes
  • Matthew A. Bershady
  • William N. Brandt
  • Kenneth C. Chambers
  • James R. A. Davenport, Western Washington University
  • Kyle S. Dawson
  • Heather Flewelling
  • Timothy M. Heckman
  • Jedidah C. Isler
  • Nick Kaiser
  • Jean-Paul Kneib
  • Chelsea L. MacLeod
  • Isabelle Paris
  • Nicholas P. Ross
  • Jessie C. Runnoe
  • Edward F. Schlafly
  • Sarah J. Schmidt
  • Donald P. Schneider
  • Axel D. Schwope
  • Yue Shen
  • Keivan G. Stassum
  • Paula Szkody
  • Christoper Z. Waters
  • Donald G. York
Document Type
Publication Date
  • Quasars: general,
  • Stars: variables: general,
  • Surveys

The Time-Domain Spectroscopic Survey (TDSS) is an SDSS-IV eBOSS subproject primarily aimed at obtaining identification spectra of ~220,000 optically variable objects systematically selected from SDSS/Pan-STARRS1 multi-epoch imaging. We present a preview of the science enabled by TDSS, based on TDSS spectra taken over ~320 deg2 of sky as part of the SEQUELS survey in SDSS-III, which is in part a pilot survey for eBOSS in SDSS-IV. Using the 15,746 TDSS-selected single-epoch spectra of photometrically variable objects in SEQUELS, we determine the demographics of our variability-selected sample and investigate the unique spectral characteristics inherent in samples selected by variability. We show that variability-based selection of quasars complements color-based selection by selecting additional redder quasars and mitigates redshift biases to produce a smooth quasar redshift distribution over a wide range of redshifts. The resulting quasar sample contains systematically higher fractions of blazars and broad absorption line quasars than from color-selected samples. Similarly, we show that M dwarfs in the TDSS-selected stellar sample have systematically higher chromospheric active fractions than the underlying M-dwarf population based on their Hα emission. TDSS also contains a large number of RR Lyrae and eclipsing binary stars with main-sequence colors, including a few composite-spectrum binaries. Finally, our visual inspection of TDSS spectra uncovers a significant number of peculiar spectra, and we highlight a few cases of these interesting objects. With a factor of ~15 more spectra, the main TDSS survey in SDSS-IV will leverage the lessons learned from these early results for a variety of time-domain science applications.

Subjects - Topical (LCSH)
Stars--Spectra; Quasars; Radio astronomy; Light curves
Citation Information
John J. Ruan, Scott F. Anderson, Paul J. Green, Eric Morganson, et al.. "The Time-Domain Spectroscopic Survey: Understanding the Optically Variable Sky with Sequels in SDSS-III" The Astrophysical Journal Vol. 825 Iss. 2 (2016) p. Article Number 137
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