Published September 20, 2017 | Version Submitted + Published
Journal Article Open

The HDUV Survey: Six Lyman Continuum Emitter Candidates at z ∼ 2 Revealed by HST UV Imaging

  • 1. ROR icon Yale-NUS College
  • 2. ROR icon Yale University
  • 3. ROR icon University of Geneva
  • 4. ROR icon University of California, Riverside
  • 5. ROR icon University of California, Santa Cruz
  • 6. ROR icon California Institute of Technology
  • 7. ROR icon Institut d'Astrophysique de Paris
  • 8. ROR icon Leiden University
  • 9. ROR icon ETH Zurich
  • 10. ROR icon University of Sussex
  • 11. ROR icon Excellence Cluster Universe
  • 12. ROR icon Max Planck Institute for Extraterrestrial Physics

Abstract

We present six galaxies at z ~ 2 that show evidence of Lyman continuum (LyC) emission based on the newly acquired UV imaging of the Hubble Deep UV legacy survey (HDUV) conducted with the WFC3/UVIS camera on the Hubble Space Telescope (HST). At the redshift of these sources, the HDUV F275W images partially probe the ionizing continuum. By exploiting the HST multiwavelength data available in the HDUV/GOODS fields, models of the UV spectral energy distributions, and detailed Monte Carlo simulations of the intergalactic medium absorption, we estimate the absolute ionizing photon escape fractions of these galaxies to be very high—typically >60% (>13% for all sources at 90% likelihood). Our findings are in broad agreement with previous studies that found only a small fraction of galaxies with high escape fraction. These six galaxies compose the largest sample yet of LyC leaking candidates at z ~ 2 whose inferred LyC flux has been observed at HST resolution. While three of our six candidates show evidence of hosting an active galactic nucleus, two of these are heavily obscured and their LyC emission appears to originate from star-forming regions rather than the central nucleus. Extensive multiwavelength data in the GOODS fields, especially the near-IR grism spectra from the 3D-HST survey, enable us to study the candidates in detail and tentatively test some recently proposed indirect methods to probe LyC leakage. High-resolution spectroscopic follow-up of our candidates will help constrain such indirect methods, which are our only hope of studying f_(esc) at z ~ 5 - 9 in the JWST era.

Additional Information

© 2017 American Astronomical Society. Received 2016 November 22; revised 2017 July 27; accepted 2017 August 22; published 2017 September 14. We thank the referee for a critical appraisal of this paper. R.N. was supported by Yale Astronomy's Dorrit Hoffleit Undergraduate Research Scholarship, Alice & Peter Tan, and Yale-NUS College's Summer Independent Research Program (SIRP) while working on this research. P.O. acknowledges support by the Swiss National Science Foundation through the SNSF Professorship grant 157567 "Galaxy Build-up at Cosmic Dawn." We are grateful to Akio Inoue for providing Monte Carlo realizations of the IGM transmission at high redshift. The primary data for this work were obtained with the Hubble Space Telescope operated by AURA, Inc., for NASA under contract NAS 5-26555. Support for this work was provided by NASA through grant HST-GO-13871 from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). Facilities: HST (ACS - , WFC3) - .

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Published - Naidu_2017_ApJ_847_12.pdf

Submitted - 1611.07038.pdf

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Additional details

Identifiers

Eprint ID
81465
Resolver ID
CaltechAUTHORS:20170914-155935445

Related works

Funding

Yale University
Alice and Peter Tan
Swiss National Science Foundation (SNSF)
157567
NASA
NAS 5-26555
NASA
HST-GO-13871

Dates

Created
2017-09-14
Created from EPrint's datestamp field
Updated
2021-11-15
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Astronomy Department