Journal article
SuperBoRG: Exploration of Point Sources at z similar to 8 in HST Parallel Fields
T Morishita, M Stiavelli, M Trenti, T Treu, GW Roberts-Borsani, CA Mason, T Hashimoto, L Bradley, D Coe, Y Ishikawa
ASTROPHYSICAL JOURNAL | IOP PUBLISHING LTD | Published : 2020
Abstract
To extend the search for quasars in the epoch of reionization beyond the tip of the luminosity function, we explore point-source candidates at redshift z ~ 8 in SuperBoRG, a compilation of ~0.4 deg2 archival medium-deep (mF160W ~ 26.5 ABmag, 5σ) parallel infrared (IR) images taken with the Hubble Space Telescope (HST). Initial candidates are selected by using the Lyman-break technique. We then carefully analyze source morphology, and robustly identify three point sources at z ~ 8. Photometric redshift analysis reveals that they are preferentially fit by extragalactic templates, and we conclude that they are unlikely to be low-z interlopers, including brown dwarfs. A clear IRAC ch2 flux exces..
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Grants
Awarded by NASA
Awarded by NASA through the Space Telescope Science Institute
Awarded by Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D)
Funding Acknowledgements
We thank the anonymous referee for reading the manuscript carefully and providing constructive comments in a timely manner despite this pandemic situation. The authors are grateful to Mariska Kriek and the MOSDEF team for developing and kindly letting us use their MOSFIRE pipeline, Elena Manjavacas for kindly supporting our observing run, Marco Chiaberge, Colin Norman, and Max Gronke for providing constructive comments on the manuscript, and Serena Manti for providing the data points of their LF models. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. This work is based in part on archival data obtained with the Spitzer Space Telescope, which was operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through grant Nos. HST-GO-15212.002, HST-GO-15702.002, and HST-AR-15804.002-A from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. M.T. acknowledges the support provided by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project No. CE170100013.