Clues to AGN Growth from Optically Variable Objects in the Hubble Ultra Deep Field

Abstract

We present a photometric search for objects with point-source components that are optically variable on timescales of weeks--months in the Hubble Ultra Deep Field (HUDF) to i'(AB)=28.0 mag. The data are split into four sub-stacks of approximately equal exposure times. Objects exhibiting the signature of optical variability are selected by studying the photometric error distribution between the four different epochs, and selecting 622 candidates as 3.0 sigma outliers from the original catalog of 4644 objects. Of these, 45 are visually confirmed as free of contamination from close neighbors or various types of image defects. Four lie within the positional error boxes of Chandra X-ray sources, and two of these are spectroscopically confirmed AGN. The photometric redshift distribution of the selected variable sample is compared to that of field galaxies, and we find that a constant fraction of ~1% of all field objects show variability over the range of 0.1<z<4.5. Combined with other recent HUDF results, as well as those of recent state-of-the-art numerical simulations, we discuss a potential link between the hierarchical merging of galaxies and the growth of AGN.

9 pages, 6 figures, accepted for publication in Astrophysical Journal, minor changes to references

References in corpus (15)

• The Demography of Massive Dark Objects in Galaxy Centres
• Energy input from quasars regulates the growth and activity of black holes and their host galaxies
• Massive Black Holes as Population III Remnants
• Wilkinson Microwave Anisotropy Probe (WMAP) First Year Observations: TE Polarization
• Black holes in galaxy mergers: The formation of red elliptical galaxies
• Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XVI. A Thirteen-Year Study of Spectral Variability in NGC 5548
• Galaxies at z~7-8: z-dropouts in the Hubble Ultra Deep Field
• Obscured AGN and the X-ray, Optical and Far-Infrared Number Counts of AGN in the GOODS Fields
• Candidates of z ~ 5.5--7 Galaxies in the HST Ultra Deep Field
• GRAPES, Grism Spectroscopy of the Hubble Ultra Deep Field: Description and Data Reduction
• Cosmological weak lensing with the HST GEMS survey
• The NICMOS Ultra Deep Field: Observations, Data Reduction, and Galaxy Photometry
• Prevalence of X-ray variability in the Chandra Deep Field South
• Tracing Galaxy Assembly: Tadpole Galaxies in the Hubble Ultra Deep Field
• A V-Band Survey for Variable Galactic Nuclei in the Hubble Deep Field

Cited by in corpus (20)

• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• The Hubble Space Telescope Wide Field Camera 3 Early Release Science data: Panchromatic Faint Object Counts for 0.2-2 microns wavelength
• On the observability of individual Population III stars and their stellar-mass black hole accretion disks through cluster caustic transits
• Probing Very Bright End of Galaxy Luminosity Function at z >~ 7 Using Hubble Space Telescope Pure Parallel Observations
• Shock Breakout in Type II Plateau Supernovae: Prospects for High Redshift Supernova Surveys
• Galaxy Mergers at z>1 in the HUDF: Evidence for a Peak in the Major Merger Rate of Massive Galaxies
• Tracing Galaxy Assembly: Tadpole Galaxies in the Hubble Ultra Deep Field
• A new extensive catalog of optically variable AGN in the GOODS Fields and a new statistical approach to variability selection
• Kiso Supernova Survey (KISS): Survey Strategy
• The James Webb Space Telescope North Ecliptic Pole Time-Domain Field -- I: Field Selection of a JWST Community Field for Time-Domain Studies
• Emission-Line Galaxies from the PEARS Hubble Ultra Deep Field: A 2-D Detection Method and First Results
• Variability and Multiwavelength Detected AGN in the GOODS Fields
• The DEEP Groth Strip Survey VI. Spectroscopic, Variability, and X-ray Detection of AGN
• The Subaru/XMM-Newton Deep Survey (SXDS) - V. Optically Faint Variable Object Survey
• The Subaru/XMM-Newton Deep Survey (SXDS) - VI. Properties of Active Galactic Nuclei Selected by Optical Variability
• Continuum optical-UV and X-ray variability of AGN: current results and future challenges
• The Abell 85 BCG: a nucleated, core-less galaxy
• Did Galaxy Assembly and Supermassive Black-Hole Growth go hand-in-hand?
• An Effective Selection Method for Low-Mass Active Black Holes and First Spectroscopic Identification
• Selection of AGN candidates in the GOODS-South Field through SPITZER/MIPS 24 $\mu$m variability