UVUDF: UV Luminosity Functions at the Cosmic High Noon

Vihang Mehta, Claudia Scarlata, Marc Rafelski, Timothy Gburek, Harry I. Teplitz, Anahita Alavi, Michael Boylan-Kolchin, Steven Finkelstein, Jonathan P. Gardner, Norman Grogin, Anton Koekemoer, Peter Kurczynski, Brian Siana, Alex Codoreanu, Duilia F. De Mello, Kyoung Soo Lee, Emmaris Soto

    Research output: Contribution to journalArticlepeer-review

    8 Scopus citations

    Abstract

    We present the rest-1500 Å UV luminosity functions (LF) for star-forming galaxies during the cosmic high noon- the peak of cosmic star formation rate at 1.5 < z < 3. We use deep NUV imaging data obtained as part of the Hubble Ultra-Violet Ultra Deep Field (UVUDF) program, along with existing deep optical and NIR coverage on the HUDF. We select F225W, F275W, and F336W dropout samples using the Lyman break technique, along with samples in the corresponding redshift ranges selected using photometric redshifts, and measure the rest-frame UV LF at z ∼ 1.7, 2.2, 3.0, respectively, using the modified maximum likelihood estimator. We perform simulations to quantify the survey and sample incompleteness for the UVUDF samples to correct the effective volume calculations for the LF. We select galaxies down to MUV = -15.9, -16.3, -16.8 and fit a faint-end slope of α = -1.20-0.13+0.10,-1.32+0.100.14, 1.39+0.08-0.12 at 1.4 < z < 1.9, 1.8 < z < 2.6, and 2.4 < z < 3.6, respectively. We compare the star formation properties of z ∼ 2 galaxies from these UV observations with results from Hα and UV +IR observations. We find a lack of high-SFR sources in the UV LF compared to the Hα and UV+IR, likely due to dusty SFGs not being properly accounted for by the generic IRX-β relation used to correct for dust. We compute a volume-averaged UV-to-Hα ratio by abundance matching the rest-frame UV LF and Hα LF. We find an increasing UV-to-Hα ratio toward low-mass galaxies (M∗ ≲ 5 ×109 M⊙). We conclude that this could be due to a larger contribution from starbursting galaxies compared to the high-mass end.

    Original languageEnglish (US)
    Article number29
    JournalAstrophysical Journal
    Volume838
    Issue number1
    DOIs
    StatePublished - Mar 20 2017

    Bibliographical note

    Publisher Copyright:
    © 2017. The American Astronomical Society. All rights reserved.

    Keywords

    • galaxies: evolution
    • galaxies: high-redshift
    • galaxies: luminosity function, mass function
    • galaxies: star formation

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