TY - JOUR
T1 - Lyman continuum leaking AGN in the SSA22 field
AU - Micheva, Genoveva
AU - Iwata, Ikuru
AU - Inoue, Akio K.
N1 - Funding Information:
This paper is based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. GM and II are supported by Japan Society for the Promotion of Science KAKENHI Grant number: 24244018. GM acknowledges support by the Swedish Research Council (Vetenskapsradet). AKI is supported by JSPS KAKENHI Grant number: 26287034. A part of this research has made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. We extend a warm thank you to Yuichi Matsuda, Katsuki Kousai, Elisabeta Lusso, Cristian Saez, and Alice Shapley for providing us with their spectra, and with some clarifications on their work and helpful advice.We also thank Andrea Grazian for useful suggestions and comments on this work.
Publisher Copyright:
© 2016 The Authors.
PY - 2017/2/11
Y1 - 2017/2/11
N2 - Subaru/SuprimeCam narrow-band photometry of the SSA22 field reveals the presence of four Lyman continuum (LyC) candidates among a sample of 14 active galactic nuclei (AGNs). Two show offsets and likely have stellar LyCin nature or are foreground contaminants. The remaining two LyC candidates are type I AGN.We argue that the average LyC escape fraction of high-redshift, low-luminosityAGNis not likely to be unity, as often assumed in the literature. From direct measurement we obtain the average LyC-to-UV flux density ratio and ionizing emissivity for a number of AGN classes and find it at least a factor of 2 lower than values obtained assuming fesc = 1. Comparing to recent Ly α forest measurements, AGNs at redshift z ~ 3 make up at most ~12 per cent and as little as ~5 per cent of the total ionizing budget. Our results suggest that AGNs are unlikely to dominate the ionization budget of the Universe at high redshifts.
AB - Subaru/SuprimeCam narrow-band photometry of the SSA22 field reveals the presence of four Lyman continuum (LyC) candidates among a sample of 14 active galactic nuclei (AGNs). Two show offsets and likely have stellar LyCin nature or are foreground contaminants. The remaining two LyC candidates are type I AGN.We argue that the average LyC escape fraction of high-redshift, low-luminosityAGNis not likely to be unity, as often assumed in the literature. From direct measurement we obtain the average LyC-to-UV flux density ratio and ionizing emissivity for a number of AGN classes and find it at least a factor of 2 lower than values obtained assuming fesc = 1. Comparing to recent Ly α forest measurements, AGNs at redshift z ~ 3 make up at most ~12 per cent and as little as ~5 per cent of the total ionizing budget. Our results suggest that AGNs are unlikely to dominate the ionization budget of the Universe at high redshifts.
KW - Cosmology: observations
KW - Diffuse radiation
KW - Galaxies: evolution
KW - Galaxies: high-redshift
KW - Intergalactic medium
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U2 - 10.1093/mnras/stw1329
DO - 10.1093/mnras/stw1329
M3 - Article
AN - SCOPUS:85014783487
SN - 0035-8711
VL - 465
SP - 302
EP - 315
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -