| 1. |
- Augustin, Ramona, et al.
(författare)
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MUSE-ALMA Haloes X : the stellar masses of gas-rich absorbing galaxies
- 2024
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Ingår i: Monthly notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 528:4, s. 6159-6166
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Tidskriftsartikel (refereegranskat)abstract
- The physical processes by which gas is accreted onto galaxies, transformed into stars, and then expelled from galaxies are of paramount importance to galaxy evolution studies. Observationally constraining each of these baryonic components in the same system, however, is challenging. Furthermore, simulations indicate that the stellar mass of galaxies is a key factor influencing CGM properties. Indeed, absorption lines detected against background quasars offer the most compelling way to study the cold gas in the circumgalactic medium (CGM). The MUSE-ALMA Haloes survey is composed of quasar fields covered with VLT/MUSE observations, comprising 32 H I absorbers at 0.2 < z < 1.4 and 79 associated galaxies, with available or upcoming molecular gas measurements from ALMA. We use a dedicated 40-orbit HST UVIS and IR WFC3 broad-band imaging campaign to characterize the stellar content of these galaxies. By fitting their spectral energy distribution, we establish they probe a wide range of stellar masses: 8.1 < log (M∗/M⊙) < 12.4. Given their star formation rates, most of these objects lie on the main sequence of galaxies. We also confirm a previously reported anticorrelation between the stellar masses and CGM hydrogen column density N (H I), indicating an evolutionary trend where higher mass galaxies are less likely to host large amounts of H I gas in their immediate vicinity up to 120 kpc. Together with other studies from the MUSE-ALMA Haloes survey, these data provide stellar masses of absorber hosts, a key component of galaxy formation and evolution, and observational constraints on the relation between galaxies and their surrounding medium.
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| 2. |
- Karki, Arjun, et al.
(författare)
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MUSE-ALMA Haloes - IX. Morphologies and stellar properties of gas-rich galaxies
- 2023
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Ingår i: Monthly notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 524:4, s. 5524-5547
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Tidskriftsartikel (refereegranskat)abstract
- Understanding how galaxies interact with the circumgalactic medium (CGM) requires determining how galaxies’ morphological and stellar properties correlate with their CGM properties. We report an analysis of 66 well-imaged galaxies detected in Hubble Space Telescope and Very Large Telescope MUSE observations and determined to be within ±500 km s−1 of the redshifts of strong intervening quasar absorbers at 0.2 ≲ z ≲ 1.4 with H I column densities NHI>1018cm−2�HI>1018cm−2. We present the geometrical properties (Sérsic indices, effective radii, axis ratios, and position angles) of these galaxies determined using GALFIT. Using these properties along with star formation rates (SFRs, estimated using the H α or [O II] luminosity) and stellar masses (M* estimated from spectral energy distribution fits), we examine correlations among various stellar and CGM properties. Our main findings are as follows: (1) SFR correlates well with M*, and most absorption-selected galaxies are consistent with the star formation main sequence of the global population. (2) More massive absorber counterparts are more centrally concentrated and are larger in size. (3) Galaxy sizes and normalized impact parameters correlate negatively with NHI, consistent with higher NHI absorption arising in smaller galaxies, and closer to galaxy centres. (4) Absorption and emission metallicities correlate with M* and specific SFR, implying metal-poor absorbers arise in galaxies with low past star formation and faster current gas consumption rates. (5) SFR surface densities of absorption-selected galaxies are higher than predicted by the Kennicutt–Schmidt relation for local galaxies, suggesting a higher star formation efficiency in the absorption-selected galaxies.
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| 3. |
- Leebens-Mack, James H., et al.
(författare)
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One thousand plant transcriptomes and the phylogenomics of green plants
- 2019
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 574:7780, s. 679-
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Tidskriftsartikel (refereegranskat)abstract
- Green plants (Viridiplantae) include around 450,000-500,000 species(1,2) of great diversity and have important roles in terrestrial and aquatic ecosystems. Here, as part of the One Thousand Plant Transcriptomes Initiative, we sequenced the vegetative transcriptomes of 1,124 species that span the diversity of plants in a broad sense (Archaeplastida), including green plants (Viridiplantae), glaucophytes (Glaucophyta) and red algae (Rhodophyta). Our analysis provides a robust phylogenomic framework for examining the evolution of green plants. Most inferred species relationships are well supported across multiple species tree and supermatrix analyses, but discordance among plastid and nuclear gene trees at a few important nodes highlights the complexity of plant genome evolution, including polyploidy, periods of rapid speciation, and extinction. Incomplete sorting of ancestral variation, polyploidization and massive expansions of gene families punctuate the evolutionary history of green plants. Notably, we find that large expansions of gene families preceded the origins of green plants, land plants and vascular plants, whereas whole-genome duplications are inferred to have occurred repeatedly throughout the evolution of flowering plants and ferns. The increasing availability of high-quality plant genome sequences and advances in functional genomics are enabling research on genome evolution across the green tree of life.
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| 4. |
- Runnholm, Axel, 1992-, et al.
(författare)
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On the evolution of the size of Lyman alpha haloes across cosmic time : no change in the circumgalactic gas distribution when probed by line emission
- 2023
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Ingår i: Monthly notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 522:3, s. 4275-4293
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Tidskriftsartikel (refereegranskat)abstract
- Lyman alpha (Ly alpha) is now routinely used as a tool for studying high-redshift galaxies, and its resonant nature means it can trace neutral hydrogen around star-forming galaxies. Integral field spectrograph measurements of high-redshift Ly alpha emitters indicate that significant extended Ly alpha halo emission is ubiquitous around such objects. We present a sample of redshift 0.23 to 0.31 galaxies observed with the Hubble Space Telescope selected to match the star formation properties of high-z samples while optimizing the observations for detection of low surface brightness Ly alpha emission. The Ly alpha escape fractions range between 0.7 and 37 per cent, and we detect extended Ly alpha emission around six out of seven targets. We find Ly alpha halo to UV scale length ratios around 6:1, which is marginally lower than high-redshift observations, and halo flux fractions between 60 and 85 per cent - consistent with high-redshift observations - when using comparable methods. However, our targets show additional extended stellar UV emission: we parametrize this with a new double exponential model. We find that this parametrization does not strongly affect the observed Ly alpha halo fractions. We find that deeper H alpha data would be required to firmly determine the origin of Ly alpha halo emission; however, there are indications that H alpha is more extended than the central FUV profile, potentially indicating conditions favourable for the escape of ionizing radiation. We discuss our results in the context of high-redshift galaxies, cosmological simulations, evolutionary studies of the circumgalactic medium in emission, and the emission of ionizing radiation.
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| 5. |
- Weng, Simon, et al.
(författare)
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MUSE-ALMA Haloes XI : gas flows in the circumgalactic medium
- 2023
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Ingår i: Monthly notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 523:1, s. 676-700
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Tidskriftsartikel (refereegranskat)abstract
- The flow of gas into and out of galaxies leaves traces in the circumgalactic medium which can then be studied using absorption lines towards background quasars. We analyse 27 log[N(H I) /cm(-2)] > 18. 0 H I absorbers at z = 0.2 to 1.4 from the MUSEALMA Haloes survey with at least one galaxy counterpart within a line of sight velocity of +/- 500 km s(-1). We perform 3D kinematic forward modelling of these associated galaxies to examine the flow of dense, neutral gas in the circumgalactic medium. From the VLT/MUSE, HST broad-band imaging, and VLT/UVES and Keck/HIRES high-resolution UV quasar spectroscopy observations, we compare the impact parameters, star-formation rates, and stellar masses of the associated galaxies with the absorber properties. We find marginal evidence for a bimodal distribution in azimuthal angles for strong H I absorbers, similar to previous studies of the Mg II and O VI absorption lines. There is no clear metallicity dependence on azimuthal angle, and we suggest a larger sample of absorbers is required to fully test the relationship predicted by cosmological hydrodynamical simulations. A case-by-case study of the absorbers reveals that ten per cent of absorbers are consistent with gas accretion, up to 30 per cent trace outflows, and the remainder trace gas in the galaxy disc, the intragroup medium, and low-mass galaxies below the MUSE detection limit. Our results highlight that the baryon cycle directly affects the dense neutral gas required for star-formation and plays a critical role in galaxy evolution.
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