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arXiv · 2201.07257

The MUSE eXtremely Deep Field: Individual detections of Ly{\alpha} haloes around rest-frame UV-selected galaxies at z~2.9-4.4

Haruka Kusakabe·Anne Verhamme·Jeremy Blaizot·Thibault Garel·Lutz Wisotzki·Floriane Leclercq·Roland Bacon·Joop Schaye·Sofia G. Gallego·Josephine Kerutt·Jorryt Matthee·Michael Maseda·Themiya Nanayakkara·Roser Pello·Johan Richard·Laurence Tresse·Tanya Urrutia·Eloise Vitte
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Abstract

Hydrogen Ly${\alpha}$ haloes (LAHs) are commonly used as a tracer of the circumgalactic medium (CGM) at high redshifts. In this work, we aim to explore the existence of Ly${\alpha}$ haloes around individual UV-selected galaxies, rather than around Ly${\alpha}$ emitters (LAEs), at high redshifts. Our sample was continuum-selected with F775W<=27.5, and spectroscopic redshifts were assigned or constrained for all the sources thanks to the deepest (100- to 140-hour) existing Very Large Telescope (VLT)/Multi-Unit Spectroscopic Explorer (MUSE) data with adaptive optics. The final sample includes 21 galaxies that are purely F775W-magnitude selected within the redshift range z=2.9-4.4 and within a UV magnitude range -20<=M1500<= -18, thus avoiding any bias toward LAEs. We tested whether galaxy's Ly${\alpha}$ emission is significantly more extended than the MUSE PSF-convolved continuum component. We find 17 LAHs and four non-LAHs. We report the first individual detections of extended Ly${\alpha}$ emission around non-LAEs. The Ly${\alpha}$ halo fraction is thus as high as $81.0^{+10.3}_{-11.2}$%, which is close to that for LAEs at z=3-6 in the literature. This implies that UV-selected galaxies generally have a large amount of hydrogen in their CGM. We derived the mean surface brightness (SB) profile for our LAHs with cosmic dimming corrections and find that Ly${\alpha}$ emission extends to 5.4 arcsec (~40 physical kpc at the midpoint redshift z=3.6) above the typical 1${\sigma}$ SB limit. The incidence rate of surrounding gas detected in Ly${\alpha}$ per one-dimensional line of sight per unit redshift, dn/dz, is estimated to be $0.76^{+0.09}_{-0.09}$ for galaxies with M1500<= -18 mag at z~3.7. Assuming that Ly${\alpha}$ emission and absorption arise in the same gas, this suggests, based on abundance matching, that LAHs trace the same gas as damped Ly${\alpha}$ systems (DLAs) and sub-DLAs.

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Haruka Kusakabe, Anne Verhamme, Jeremy Blaizot, Thibault Garel, Lutz Wisotzki, Floriane Leclercq, Roland Bacon, Joop Schaye, Sofia G. Gallego, Josephine Kerutt, Jorryt Matthee, Michael Maseda, Themiya Nanayakkara, Roser Pello, Johan Richard, Laurence Tresse, Tanya Urrutia, Eloise Vitte. 2022-01-18. The MUSE eXtremely Deep Field: Individual detections of Ly{\alpha} haloes around rest-frame UV-selected galaxies at z~2.9-4.4. https://doi.org/10.1051/0004-6361%2F202142302

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