The Time-Domain Spectroscopic Survey: Understanding the Optically Variable Sky with SEQUELS in SDSS-III

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 deg^2 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 H-alpha 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.

17 pages, 14 figures, submitted to ApJ

References in corpus (41)

• The 2.5 m Telescope of the Sloan Digital Sky Survey
• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• Baryon Acoustic Oscillations in the Ly-α forest of BOSS quasars
• Constraining the Age-Activity Relation for Cool Stars: The SDSS DR5 Low-Mass Star Spectroscopic Sample
• The Catalina Surveys Periodic Variable Star Catalog
• The accretion origin of the Milky Way's stellar halo
• Stellar SEDs from 0.3-2.5 Microns: Tracing the Stellar Locus and Searching for Color Outliers in SDSS and 2MASS
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• Tracing Galaxy Formation with Stellar Halos II: Relating Substructure in Phase- and Abundance-Space to Accretion Histories
• A Catalog of Broad Absorption Line Quasars in Sloan Digital Sky Survey Data Release 5
• X-ray spectral properties of AGN in the Chandra Deep Field South
• A possible close supermassive black-hole binary in a quasar with optical periodicity
• Is Quasar Optical Variability a Damped Random Walk?
• SDSS Standard Star Catalog for Stripe 82: the Dawn of Industrial 1% Optical Photometry
• The Stellar Populations of Praesepe and Coma Berenices
• Kepler Flares II: The Temporal Morphology of White-Light Flares on GJ 1243
• Think Outside the Color Box: Probabilistic Target Selection and the SDSS-XDQSO Quasar Targeting Catalog
• Quasar Accretion Disks Are Strongly Inhomogeneous
• The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Quasar Target Selection
• The Sloan Digital Sky Survey Reverberation Mapping Project: Technical Overview
• The Intrinsic Fraction of Broad Absorption Line Quasars
• Clustering Analyses of 300,000 Photometrically Classified Quasars--I. Luminosity and Redshift Evolution in Quasar Bias
• Quasar Broad Absorption Line Variability on Multi-Year Time Scales
• On the variability of quasars: a link between Eddington ratio and optical variability?
• M Dwarfs in SDSS Stripe 82: Photometric Light Curves and Flare Rate Analysis
• BOSS Ultracool Dwarfs I: Colors and Magnetic Activity of M and L dwarfs
• Clustering Analyses of 300,000 Photometrically Classified Quasars--II. The Excess on Very Small Scales
• Characteristic Signatures in the Thermal Emission from Accreting Binary Black Holes
• Quasar Selection Based on Photometric Variability
• A Periodically Varying Luminous Quasar at z=2 from the Pan-STARRS1 Medium Deep Survey: A Candidate Supermassive Black Hole Binary in the Gravitational Wave-Driven Regime
• Revealing Substructure in the Galactic Halo - The SEKBO RR Lyrae Survey
• Exploring the Local Milky Way: M Dwarfs as Tracers of Galactic Populations
• Modeling of Emission Signatures of Massive Black Hole Binaries: I Methods
• The Sloan Digital Sky Survey Reverberation Mapping Project: Rapid CIV Broad Absorption Line Variability
• Discovery of a ~5 day characteristic timescale in the Kepler power spectrum of Zw 229-15
• Using the Galactic Dynamics of M7 Dwarfs to Infer the Evolution of Their Magnetic Activity
• The distribution of absorption in AGN detected in the XMM-Newton observations of the CDFS
• The Nature of Transition Blazars
• A Glimpse at Quasar Host Galaxy Far-UV Emission, Using DLAs as Natural Coronagraphs
• Are many radio-selected BL Lacs radio quasars in disguise?
• Exploring the Variable Sky with the Sloan Digital Sky Survey

Cited by in corpus (18)

• Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
• The Sixteenth Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
• The Thirteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey MApping Nearby Galaxies at Apache Point Observatory
• The Sloan Digital Sky Survey Quasar Catalog: Fourteenth Data Release
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Baryon acoustic oscillations with Lyman-$\alpha$ forests
• The Fifteenth Data Release of the Sloan Digital Sky Surveys: First Release of MaNGA Derived Quantities, Data Visualization Tools and Stellar Library
• A Mid-IR Selected Changing-Look Quasar and Physical Scenarios for Abrupt AGN Fading
• Machine-Learned Identification of RR Lyrae Stars from Sparse, Multi-band Data: the PS1 Sample
• The completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Large-scale Structure Catalogues and Measurement of the isotropic BAO between redshift 0.6 and 1.1 for the Emission Line Galaxy Sample
• The Time Domain Spectroscopic Survey: Changing-Look Quasar Candidates from Multi-Epoch Spectroscopy in SDSS-IV
• Discovery of A Mg II Changing-look AGN and its Implications for a Unification Sequence of Changing-look AGNs
• Rapid "Turn-on" of type 1 AGN in a quiescent early type galaxy SDSS1115+0544
• Classifying Single Stars and Spectroscopic Binaries Using Optical Stellar Templates
• High-redshift Extreme Variability Quasars from Sloan Digital Sky Survey Multi-Epoch Spectroscopy
• The Time-Domain Spectroscopic Survey: Target Selection for Repeat Spectroscopy
• The Time-Domain Spectroscopic Survey: Radial Velocity Variability in Dwarf Carbon Stars
• Multivariate Time-series Analysis of Variable Objects in the Gaia Mission
• A Geometric Probe of Cosmology: I. Gravitational Lensing Time Delays and Quasar Reverberation Mapping