Hydrogen Lyα 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 Lyα haloes around individual UV-selected galaxies, rather than around Lyα 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-h) 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 Lyα 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 Lyα emission around non-LAEs. The Lyα halo fraction is thus as high as 81.0−11.2+10.3%, 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 Lyα emission extends to 5.4 arcsec (≃40 physical kpc at the midpoint redshift z = 3.6) above the typical 1σ SB limit. The incidence rate of surrounding gas detected in Lyα 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 Lyα emission and absorption arise in the same gas, this suggests, based on abundance matching, that LAHs trace the same gas as damped Lyα systems (DLAs) and sub-DLAs.
Astronomy & Astrophysics
We thank the anonymous referee for constructive comments and suggestions. We would like to express our gratitude to Edmund Christian Herenz, Leindert Boogard, Miroslava Dessauges, Moupiya Maji, Valentin Mauerhofer, Charlotte Paola Simmonds Wagemann, Masami Ouchi, Kazuhiro Shimasaku, Akio Inoue, and Rieko Momose for giving insightful comments and suggestions. H.K. is grateful to Liam McCarney for useful suggestions on English writing through the UniGE’s Tandems linguistiques. H.K. acknowledges support from Swiss Government Excellence Scholarships and Japan Society for the Promotion of Science (JSPS) Overseas Research Fellowship. H.K., F.L., and A.V. are supported by the SNF grant PP00P2 176808. A.V. and T.G. are supported by the ERC Starting Grant 757258“TRIPLE”. This work was supported by the Programme National Cosmology et Galaxies (PNCG) of CNRS/INSU with INP and IN2P3, co-funded by CEA and CNES. This work is based on observations taken by VLT, which is operated by European Southern Observatory. This research made use of Astropy, which is a community-developed core Python package for Astronomy (Astropy Collaboration 2013, 2018), and other software and packages: MARZ, MPDAF (Piqueras et al. 2019), PHOTUTILS, Numpy (Harris et al. 2020), Scipy (Virtanen et al. 2020), and matplotlib (Hunter 2007).
Kusakabe H, Verhamme A, Blaizot J, et al. The MUSE eXtremely Deep Field: Individual detections of Lyα haloes around rest-frame UV-selected galaxies at z ≃ 2.9–4.4. Astronomy & Astrophysics. 2022;660. doi:10.1051/0004-6361/202142302
Kusakabe, H., Verhamme, A., Blaizot, J., Garel, T., Wisotzki, L., Leclercq, F., … Vitte, E. (2022). The MUSE eXtremely Deep Field: Individual detections of Lyα haloes around rest-frame UV-selected galaxies at z ≃ 2.9–4.4. Astronomy & Astrophysics. EDP Sciences. https://doi.org/10.1051/0004-6361/202142302
Kusakabe, Haruka, Anne Verhamme, Jérémy Blaizot, Thibault Garel, Lutz Wisotzki, Floriane Leclercq, Roland Bacon, et al. “The MUSE EXtremely Deep Field: Individual Detections of Lyα Haloes around Rest-Frame UV-Selected Galaxies at z ≃ 2.9–4.4.” Astronomy & Astrophysics. EDP Sciences, 2022. https://doi.org/10.1051/0004-6361/202142302.
H. Kusakabe et al., “The MUSE eXtremely Deep Field: Individual detections of Lyα haloes around rest-frame UV-selected galaxies at z ≃ 2.9–4.4,” Astronomy & Astrophysics, vol. 660. EDP Sciences, 2022.
Kusakabe H, Verhamme A, Blaizot J, Garel T, Wisotzki L, Leclercq F, Bacon R, Schaye J, Gallego SG, Kerutt J, Matthee JJ, Maseda M, Nanayakkara T, Pelló R, Richard J, Tresse L, Urrutia T, Vitte E. 2022. The MUSE eXtremely Deep Field: Individual detections of Lyα haloes around rest-frame UV-selected galaxies at z ≃ 2.9–4.4. Astronomy & Astrophysics. 660, A44.
Kusakabe, Haruka, et al. “The MUSE EXtremely Deep Field: Individual Detections of Lyα Haloes around Rest-Frame UV-Selected Galaxies at z ≃ 2.9–4.4.” Astronomy & Astrophysics, vol. 660, A44, EDP Sciences, 2022, doi:10.1051/0004-6361/202142302.