First HETDEX Spectroscopic Determinations of Lyα and UV Luminosity Functions at z=2–3: Bridging a Gap between Faint AGNs and Bright Galaxies

dc.contributor.authorJarvis, Matt J.
dc.date.accessioned2022-09-15T10:27:19Z
dc.date.available2022-09-15T10:27:19Z
dc.date.issued2021
dc.description.abstractWe present Lyα and ultraviolet (UV)-continuum luminosity functions (LFs) of galaxies and active galactic nuclei (AGNs) at z = 2.0–3.5 determined by the untargeted optical spectroscopic survey of the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX). We combine deep Subaru imaging with HETDEX spectra resulting in 11.4 deg2 of fiber spectra sky coverage, obtaining 18,320 galaxies spectroscopically identified with Lyα emission, 2126 of which host type 1 AGNs showing broad (FWHM > 1000 km s−1 ) Lyα emission lines. We derive the Lyα (UV) LF over 2 orders of magnitude covering bright galaxies and AGNs in log erg s 43.3 45.5 LLya [] – -1 = (−27 < MUV < −20) by the 1/Vmax estimator. Our results reveal that the bright-end hump of the Lyα LF is composed of type 1 AGNs. In conjunction with previous spectroscopic results at the faint end, we measure a slope of the best-fit Schechter function to be a = - - + Sch 1.70 0.14 0.13, which indicates that αSch steepens from z = 2–3 toward high redshift. Our UV LF agrees well with previous AGN UV LFs and extends to faint-AGN and bright-galaxy regimes. The number fraction of Lyαemitting objects (XLAE) increases from MUV* ~ -21 to bright magnitude due to the contribution of type 1 AGNs, while previous studies claim that XLyα decreases from faint magnitudes to M* UV, suggesting a valley in the XLyα–magnitude relation at M* UV. Comparing our UV LF of type 1 AGNs at z = 2–3 with those at z = 0, we find that the number density of faint (MUV > −21) type 1 AGNs increases from z ∼ 2 to 0, as opposed to the evolution of bright (MUV < −21) type 1 AGNs, suggesting AGN downsizing in the rest-frame UV luminosityen_US
dc.identifier.citationZhang, Y., Ouchi, M., Gebhardt, K., Mentuch Cooper, E., Liu, C., Davis, D., Jeong, D., Farrow, D., Finkelstein, S., Gawiser, E., Hill, G., Harikane, Y., Kakuma, R., Acquaviva, V., Casey, C., Fabricius, M., Hopp, U., Jarvis, M., Landriau, M., Mawatari, K., Mukae, S., Ono, Y., Sakai, N. and Schneider, D., 2022. First HETDEX Spectroscopic Determinations of Lyα and UV Luminosity Functions at z = 2–3: Bridging a Gap between Faint AGNs and Bright Galaxies.en_US
dc.identifier.uri10.3847/1538-4357/ac1e97
dc.identifier.urihttp://hdl.handle.net/10566/7894
dc.language.isoenen_US
dc.publisherThe Astrophysical Journalen_US
dc.subjecthigh-redshift galaxiesen_US
dc.subjectgalaxy evolutionen_US
dc.subjectlyman-alpha galaxiesen_US
dc.subjectactive galactic nucleien_US
dc.titleFirst HETDEX Spectroscopic Determinations of Lyα and UV Luminosity Functions at z=2–3: Bridging a Gap between Faint AGNs and Bright Galaxiesen_US
dc.typeArticleen_US

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