We report the direct detection of Lyman continuum (LyC) emission from nine galaxies and one active galactic nucleus at z ∼ 1.1–1.6 in the GOODS-North field using deep observations from the Ultraviolet Imaging Telescope (UVIT) on board AstroSat. The absolute escape fraction of the sources estimated from the far-ultraviolet and Hα-line luminosities using Monte Carlo analysis of two intergalactic medium models span a range ∼10%–55%. The rest-frame UV wavelength of the sources falls in the extreme-ultraviolet regime ∼550–700 Å, the shortest LyC wavelength range probed so far. This redshift range remains devoid of direct detections of LyC emission due to the instrumental limitations of previously available facilities. With UVIT having very low detector noise, each of these sources is detected with an individual signal-to-noise ratio (S/N) > 3, while for the stack of six sources, we achieve an S/N ∼ 7.4. The LyC emission is seen to be offset from the optical centroids and extended beyond the UVIT point-spread function of 16 in most of the sources. This sample fills an important niche between GALEX and Cosmic Origins Spectrograph at low z and Hubble Space Telescope's Wide Field Camera 3 at high z and is crucial in understanding the evolution of LyC leakers.
Lyman Continuum Leakers in the AstroSat Ultraviolet Deep Field: Extreme-ultraviolet Emitters at the Cosmic Noon
Abstract
Copyright and License
© 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Acknowledgement
S.D. and K.S. acknowledge support from the Indian Space Research Organisation (ISRO) funding under project PAO/REF/CP167. This publication uses the UVIT data obtained from the Indian Space Science Data Centre (ISSDC) of ISRO, where the data for AstroSat mission is archived. The UVIT project is a collaboration between IIA, IUCAA, TIFR, ISRO from India and CSA from Canada. This work is based on observations taken by the 3D-HST Treasury Program (GO 12177 and 12328) with the NASA/ESA HST, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.
Facilities
HST (WFC3) - , ASTROSAT(UVIT) -
Software References
astropy (Astropy Collaboration et al. 2013), Source Extractor (Bertin & Arnouts 1996)
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Additional details
- ISSN
- 2041-8213
- Indian Space Research Organisation
- PAO/REF/CP167
- National Aeronautics and Space Administration
- NAS5-26555
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)