Abstract / Description of output
We measure the rest-frame ultraviolet (UV) luminosity function (LF) at z ∼ 4 self-consistently over a wide range in absolute magnitude (−27 ≲ MUV ≲ −20). The LF is measured with 46 904 sources selected using a photometric redshift approach over ∼6 deg2 of the combined Cosmological Evolution Survey and XMM–Newton
Large-Scale Structure fields. We simultaneously fit for both active
galactic nuclei (AGNs) and galaxy LFs using a combination of Schechter
or double power law (DPL) functions alongside a single power law for the
faint-end slope of the AGN LF. We find a lack of evolution in the shape
of the bright end of the Lyman-break galaxy (LBG) component when
compared to other studies at z ≃ 5 and evolutionary recipes for
the UV LF. Regardless of whether the LBG LF is fit with a Schechter
function or DPL, AGNs are found to dominate at MUV < −23.5. We measure a steep faint-end slope of the AGN LF with αAGN=−2.09+0.35−0.38 (−1.66+0.29−0.58)
when fit alongside a Schechter function (DPL) for the galaxies. Our
results suggest that if AGNs are morphologically selected it results in a
bias to lower number densities. Only by considering the full galaxy
population over the transition region from AGN to LBG domination can an
accurate measurement of the total LFs be attained.
Original language | English |
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Pages (from-to) | 1771-1783 |
Number of pages | 13 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 494 |
Issue number | 2 |
Early online date | 13 Mar 2020 |
DOIs | |
Publication status | Published - 1 May 2020 |
Keywords / Materials (for Non-textual outputs)
- astro-ph.GA