Document Type

Article

Publication Date

7-12-2016

Keywords

Quasars: general, Stars: variables: general, Surveys

Abstract

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.

Publication Title

The Astrophysical Journal

Volume

825

Issue

2

First Page

Article Number 137

DOI

10.3847/0004-637X/825/2/137

Required Publisher's Statement

Published 2016 July 12 • © 2016. The American Astronomical Society. All rights reserved.

Link to journal article: http://iopscience.iop.org/article/10.3847/0004-637X/825/2/137?pageTitle=IOPscience

http://dx.doi.org/10.3847/0004-637X/825/2/137

Subjects - Topical (LCSH)

Stars--Spectra; Quasars; Radio astronomy; Light curves

Genre/Form

articles

Type

Text

Language

English

Format

application/pdf

Share

COinS