GALEX observations of quasar variability in the ultraviolet

Abstract

Using archival observations recorded over a 5+ year timeframe with the NASA Galaxy Evolution Explorer (GALEX) satellite, we present a study of the ultraviolet (UV) variability of 4360 quasars of redshifts up to z=2.5 that have optical counterparts in the Sloan Digital Sky Survey DR5 spectroscopic catalog. The observed changes in both the far UV (FUV: 1350-1785A) and near UV (NUV: 1770-2830A) AB magnitudes as a function of time may help differentiate between models of the emission mechanisms thought to operate in these active galaxies. A list of NUV and FUV variable quasars was derived from the UV light-curves of sources with 5 or more observational visits by GALEX that spanned a time-frame greater than 3 months. By measuring the error in the derived mean UV magnitude from the series of GALEX observations for each source, quasars whose UV variability was greater than the 3-sigma variance from the mean observed value were deemed to be (intrinsically) UV variable. This conservative selection criterion (which was applied to both FUV and NUV observations) resulted in identifying 550 NUV and 371 FUV quasars as being statistically significant UV variable objects.

A&A Accepted, spelling of author's name corrected (Neill)

References in corpus (11)

• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• The Sloan Digital Sky Survey Quasar Catalog IV. Fifth Data Release
• UV/Optical Detections of Candidate Tidal Disruption Events by GALEX and CFHTLS
• On the variability of quasars: a link between Eddington ratio and optical variability?
• The dependence of quasar variability on black hole mass
• Statistical Properties of the GALEX/SDSS matched source catalogs, and classification of the UV sources
• X-Ray Properties of Narrow-Line Seyfert 1 Galaxies with Very Small Broad-Line Widths
• The UV Properties of SDSS Selected Quasars
• The Second Galex Ultraviolet Variability (GUVV-2) Catalog
• Quasar optical variability: searching for interband time delays
• Exploring the Variable Sky with the Sloan Digital Sky Survey

Cited by in corpus (36)

• A Description of Quasar Variability Measured Using Repeated SDSS and POSS Imaging
• Science with a wide-field UV transient explorer
• Photometric redshifts and quasar probabilities from a single, data-driven generative model
• The Ultraviolet Sky: An Overview from the GALEX Surveys
• Dust-Deficient Palomar-Green Quasars and the Diversity of AGN Intrinsic IR Emission
• Nebular Attenuation in Hα-selected Star-forming Galaxies at z=0.8 from the NewHα Survey
• The Galaxy Evolution Explorer (GALEX). Its legacy of UV surveys, and science highlights
• Minor Contribution of Quasars to Ionizing Photon Budget at z~6: Update on Quasar Luminosity Function at the Faint-end with Subaru/Suprime-Cam
• The GALEX Time Domain Survey I. Selection and Classification of Over a Thousand UV Variable Sources
• Testing the relativistic Doppler boost hypothesis for supermassive black hole binary candidates
• No excess of bright galaxies around the redshift 7.1 quasar ULAS J1120+0641
• Variability in Low Ionization Broad Absorption Line Outflows
• A comparative study of optical/ultraviolet variability of narrow-line Seyfert 1 and broad-line Seyfert 1 active galactic nuclei
• Sensitive Chandra coverage of a representative sample of weak-line quasars: revealing the full range of X-ray properties
• Long term γ -ray variability of blazars
• A multi-epoch spectroscopic study of the BAL quasar APM 08279+5255: I. C IV absorption variability
• Modelling the Multiwavelength Variability of Mrk 335 using Gaussian Processes
• Testing the relativistic Doppler boost hypothesis for the binary candidate quasar PG1302-102 with multi-band Swift data
• The Timescale-Dependent Color Variability of Quasars Viewed with GALEX
• The Infrared Medium-deep Survey. VI. Discovery of Faint Quasars at $z\sim 5$ with a Medium-band-based Approach
• Ionization driven intrinsic absorption line variability of BAL quasars in the Stripe 82 region
• The White Dwarf Binary Pathways Survey VII: Evidence for a bi-modal distribution of post mass transfer systems?
• Correlation between Optical and UV Variability of Quasars
• Transient C IV Broad Absorption Lines in radio detected QSOs
• The Relativistic Jet-Accretion Flow-Wind Connection in Mrk\,231
• Deceleration of CIV and SiIV broad absorption lines in X-ray bright quasar SDSS-J092345+512710
• Behaviour of the MgII 2798AA Line Over the Full Range of AGN Variability
• The Extreme Ultraviolet Variability of Quasars
• Mid-infrared Variability of gamma-ray emitting blazars
• Wide-field Ultraviolet Imager for Astronomical Transient Studies
• Searching for Short-Timescale Variability in the Ultraviolet with the GALEX gPhoton Archive I.: Artifacts and Spurious Periodicities
• Estimating the Jet Power of Mrk\,231 During the 2017-2018 Flare
• Long term Ultra-Violet Variability of Seyfert galaxies
• The Variability of the Narrow-line Seyfert 1 Galaxies from the PanSTARRS's View
• Variable gamma-ray sky at 1 GeV
• The Near Ultraviolet Transient Surveyor (NUTS): An ultraviolet telescope to observe variable sources