Browsing by Author "Maseda, Michael"

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    An atlas of MUSE observations towards twelve massive lensing clusters
    (2021) Richard, Johan; Claeyssens, Adelaide; Lagattuta, David; Guaita, Lucia; Bauer, Franz Erik; Pello, Roser; Carton, David; Bacon, Roland; Soucail, Genevieve; Lyon, Gonzalo Prieto; Kneib, Jean-Paul; Mahler, Guillaume; Clement, Benjamin; Mercier, Wilfried; Variu, Andrei; Tamone, Amelie; Ebeling, Harald; Schmidt, Kasper B.; Nanayakkara, Themiya; Maseda, Michael; Weilbacher, Peter M.; Bouche, Nicolas; Bouwens, Rychard J.; Wisotzki, Lutz; de la Vieuville, Geoffroy; Martinez, Johany; Patricio, Vera
    Context. Spectroscopic surveys of massive galaxy clusters reveal the properties of faint background galaxies thanks to the magnification provided by strong gravitational lensing.Aims. We present a systematic analysis of integral-field-spectroscopy observations of 12 massive clusters, conducted with the Multi Unit Spectroscopic Explorer (MUSE). All data were taken under very good seeing conditions (similar to 0 ''.6) in effective exposure times between two and 15 h per pointing, for a total of 125 h. Our observations cover a total solid angle of similar to 23 arcmin(2) in the direction of clusters, many of which were previously studied by the MAssive Clusters Survey, Frontier Fields (FFs), Grism Lens-Amplified Survey from Space and Cluster Lensing And Supernova survey with Hubble programmes. The achieved emission line detection limit at 5 sigma for a point source varies between (0.77-1.5) x 10(-18) erg s(-1) cm(-2) at 7000 angstrom.Methods. We present our developed strategy to reduce these observational data, detect continuum sources and line emitters in the datacubes, and determine their redshifts. We constructed robust mass models for each cluster to further confirm our redshift measurements using strong-lensing constraints, and identified a total of 312 strongly lensed sources producing 939 multiple images.Results. The final redshift catalogues contain more than 3300 robust redshifts, of which 40% are for cluster members and similar to 30% are for lensed Lyman-alpha emitters. Fourteen percent of all sources are line emitters that are not seen in the available HST images, even at the depth of the FFs (similar to 29 AB). We find that the magnification distribution of the lensed sources in the high-magnification regime (mu=2-25) follows the theoretical expectation of N(z) proportional to mu(-2). The quality of this dataset, number of lensed sources, and number of strong-lensing constraints enables detailed studies of the physical properties of both the lensing cluster and the background galaxies. The full data products from this work, including the datacubes, catalogues, extracted spectra, ancillary images, and mass models, are made available to the community.
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    Measuring the Average Molecular Gas Content of Star-forming Galaxies at z=3-4
    (2021) Boogaard, Leindert A.; Bouwens, Rychard J.; Riechers, Dominik; van der Werf, Paul; Bacon, Roland; Matthee, Jorryt; Stefanon, Mauro; Feltre, Anna; Maseda, Michael; Inami, Hanae; Aravena, Manuel; Brinchmann, Jarle; Carilli, Chris; Contini, Thierry; Decarli, Roberto; Gonzalez-Lopez, Jorge; Nanayakkara, Themiya; Walter, Fabian
    We study the molecular gas content of 24 star-forming galaxies at z = 3-4, with a median stellar mass of 10(9.1) M-circle dot, from the MUSE Hubble Ultra Deep Field (HUDF) Survey. Selected by their Ly alpha lambda 1216 emission and H (F160W)-band magnitude, the galaxies show an average < EWLy alpha 0 > approximate to 20 angstrom, below the typical selection threshold for Ly alpha emitters (EWLy alpha 0 > 25 angstrom), and a rest-frame UV spectrum similar to Lyman-break galaxies. We use rest-frame optical spectroscopy from KMOS and MOSFIRE, and the UV features observed with MUSE, to determine the systemic redshifts, which are offset from Ly alpha by = 346 km s(-1), with a 100 to 600 km s(-1) range. Stacking (CO)-C-12 J = 4 -> 3 and [C I]P-3(1) -> P-3(0) (and higher-J CO lines) from the ALMA Spectroscopic Survey of the HUDF, we determine 3 sigma upper limits on the line luminosities of 4.0 x 10(8) K km s(-1)pc(2) and 5.6 x 10(8) K km s(-1)pc(2), respectively (for a 300 km s(-1) line width). Stacking the 1.2 mm and 3 mm dust-continuum flux densities, we find a 3 sigma upper limits of 9 mu Jy and 1.2 mu Jy, respectively. The inferred gas fractions, under the assumption of a "Galactic" CO-to-H-2 conversion factor and gas-to-dust ratio, are in tension with previously determined scaling relations. This implies a substantially higher alpha(CO) >= 10 and delta(GDR) >= 1200, consistent with the subsolar metallicity estimated for these galaxies (12 + log(O/H) approximate to 7.8 +/- 0.2). The low metallicity of z >= 3 star-forming galaxies may thus make it very challenging to unveil their cold gas through CO or dust emission, warranting further exploration of alternative tracers, such as [C II].