MUSE–ALMA haloes VII: survey science goals & design, data processing and final catalogues

Abstract

The gas cycling in the circumgalactic regions of galaxies is known to be multi-phase. The MUSE-ALMA Haloes survey gathers a large multi-wavelength observational sample of absorption and emission data with the goal to significantly advance our understanding of the physical properties of such CGM gas. A key component of the MUSE-ALMA Haloes survey is the multi-facility observational campaign conducted with VLT/MUSE, ALMA and HST. MUSE-ALMA Haloes targets comprise 19 VLT/MUSE IFS quasar fields, including 32 zabs <0.85 strong absorbers with measured $N(\rm {H\,{\small I}})$ ≥1018 cm-2 from UV-spectroscopy. We additionally use a new complementary HST medium program to characterise the stellar content of the galaxies through a 40-orbit three-band UVIS and IR WFC3 imaging. Beyond the absorber-selected targets, we detect 3658 sources all fields combined, including 703 objects with spectroscopic redshifts. This galaxy-selected sample constitutes the main focus of the current paper. We have secured millimeter ALMA observations of some of the fields to probe the molecular gas properties of these objects. Here, we present the overall survey science goals, target selection, observational strategy, data processing and source identification of the full sample. Furthermore, we provide catalogues of magnitude measurements for all objects detected in VLT/MUSE, ALMA and HST broad-band images and associated spectroscopic redshifts derived from VLT/MUSE observations. Together, this data set provides robust characterisation of the neutral atomic gas, molecular gas and stars in the same objects resulting in the baryon census of condensed matter in complex galaxy structures.

Detection of the Diffuse H i Emission in the Circumgalactic Medium of NGC 891 and NGC 4565

“…Ly𝛼 absorption studies of H i in the CGM of the Milky Way have shown evidence for a large amount of atomic gas at N(H i) ≥ 10 18 cm −2 (e.g., Richter et al 2017). The circumgalactic H i in external galaxies has been studied using Ly𝛼 absorption lines at 𝑧 ⪅ 0.2−0.85 (e.g., Borthakur et al 2016;Péroux et al 2022). These studies have revealed a strong correlation between the atomic gas mass fraction (M HI /M ★ ) and the impact-parameter-corrected equivalent width of Ly𝛼 absorbers, suggesting a physical connection between the atomic ISM and the CGM.…”

The MUSE Ultra Deep Field (MUDF). III. Hubble Space Telescope WFC3 Grism Spectroscopy and Imaging

“…This enriched gas comprises the intergalactic medium (IGM) and circumgalactic medium (CGM), which consists of diffuse, multiphase gas that lies within the virial radii of galaxies (Tumlinson et al 2017). This tenuous reservoir plays a crucial role in regulating a galaxy's supply of gas, as stellar-driven feedback deposits enriched material beyond the disk that can recycle through the galaxy on a variety of timescales (Fielding et al 2017;Peroux & Howk 2020;Chadayammuri et al 2022;Pandya et al 2022;Péroux et al 2022). However, studying the connections between low-mass galaxies and the CGM at high redshift is challenging because the gas structures are intrinsically faint.…”

Metal line emission from galaxy haloes at z~1

“…Significant progress has been made over the last few decades in statistically characterizing the distribution and physical conditions of the multiphase halo gas by cross-correlating absorption lines and galaxy surveys at ★ E-mail: rajeshwari.dutta@unimib.it 𝑧 < 2 (e.g. Prochaska et al 2011a;Tumlinson et al 2013;Chen et al 2020;Dutta et al 2020Dutta et al , 2021Wilde et al 2021;Berg et al 2022;Péroux et al 2022;Weng et al 2022), and at 𝑧 > 2 (e.g. Rudie et al 2012;Turner et al 2014;Bielby et al 2020;Lofthouse et al 2020Lofthouse et al , 2023Muzahid et al 2021).…”