Browsing by Author "Guaita, Lucia"

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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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    EVOLUTION IN THE CONTINUUM MORPHOLOGICAL PROPERTIES OF Lyα-EMITTING GALAXIES FROM z=3.1 TO z=2.1
    (2012) Bond, Nicholas A.; Gawiser, Eric; Guaita, Lucia; Padilla, Nelson; Gronwall, Caryl; Ciardullo, Robin; Lai, Kamson
    We present a rest-frame ultraviolet morphological analysis of 108 z similar or equal to 2.1 Ly alpha emitters (LAEs) in the Extended Chandra Deep Field South and compare it to a similar sample of 171 LAEs at z similar or equal to 3.1. Using Hubble Space Telescope images from the Galaxy Evolution from Morphology and SEDs survey, Great Observatories Origins Deep Survey, and Hubble Ultradeep Field, we measure size and photometric component distributions, where photometric components are defined as distinct clumps of UV-continuum emission. At both redshifts, >80% of LAEs have observed half-light radii < 2 kpc, but the median half-light radius rises from 0.95 +/- 0.04 kpc at z = 3.1 to 1.41 +/- 0.14 kpc at z = 2.1. A similar evolution is seen in the sizes of individual rest-UV components, but there is no evidence for evolution in the number of multi-component systems. In the z = 2.1 sample, we see clear correlations between the size of an LAE and other physical properties derived from its spectral energy distribution (SED). LAEs are found to be larger for galaxies with higher stellar mass, star formation rate, and dust obscuration, but there is no evidence for a trend between equivalent width and half-light radius at either redshift. The presence of these correlations suggests that a wide range of objects are being selected by LAE surveys at z similar or equal to 2, including a significant fraction of objects for which a massive and moderately extended population of old stars underlies the young starburst giving rise to the Ly alpha emission.
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    Pilot-WINGS: An extended MUSE view of the structure of Abell 370
    (2022) Lagattuta, David J.; Richard, Johan; Bauer, Franz Erik; Cerny, Catherine; Claeyssens, Adelaide; Guaita, Lucia; Jauzac, Mathilde; Jeanneau, Alexandre; Koekemoer, Anton M.; Mahler, Guillaume; Prieto Lyon, Gonzalo; Acebron, Ana; Meneghetti, Massimo; Niemiec, Anna; Zitrin, Adi; Bianconi, Matteo; Connor, Thomas; Cen, Renyue; Edge, Alastair; Faisst, Andreas L.; Limousin, Marceau; Massey, Richard; Sereno, Mauro; Sharon, Keren; Weaver, John R.
    We investigate the strong-lensing cluster Abell 370 (A370) using a wide Integral Field Unit (IFU) spectroscopic mosaic from the Multi-Unit Spectroscopic Explorer (MUSE). IFU spectroscopy provides significant insight into the structure and mass content of galaxy clusters, yet IFU-based cluster studies focus almost exclusively on the central Einstein-radius region. Covering over 14 arcmin(2), the new MUSE mosaic extends significantly beyond the A370 Einstein radius, providing, for the first time, a detailed look at the cluster outskirts. Combining these data with wide-field, multi-band Hubble Space Telescope (HST) imaging from the BUFFALO project, we analyse the distribution of objects within the cluster and along the line of sight. Identifying 416 cluster galaxies, we use kinematics to trace the radial mass profile of the halo, providing a mass estimate independent from the lens model. We also measure radially averaged properties of the cluster members, tracking their evolution as a function of infall. Thanks to the high spatial resolution of our data, we identify six cluster members acting as galaxy-galaxy lenses, which constrain localized mass distributions beyond the Einstein radius. Finally, taking advantage of MUSE's 3D capabilities, we detect and analyse multiple spatially extended overdensities outside of the cluster that influence lensing-derived halo mass estimates. We stress that much of this work is only possible thanks to the robust, extended IFU coverage, highlighting its importance even in less optically dense cluster regions. Overall, this work showcases the power of combining HST + MUSE, and serves as the initial step towards a larger and wider program targeting several clusters.
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    SPECTRAL ENERGY DISTRIBUTION FITTING WITH MARKOV CHAIN MONTE CARLO: METHODOLOGY AND APPLICATION TO z=3.1 Lyα-EMITTING GALAXIES
    (2011) Acquaviva, Viviana; Gawiser, Eric; Guaita, Lucia
    We present GalMC, a Markov Chain Monte Carlo (MCMC) algorithm designed to fit the spectral energy distributions (SEDs) of galaxies to infer physical properties such as age, stellar mass, dust reddening, metallicity, redshift, and star formation rate. We describe the features of the code and the extensive tests conducted to ensure that our procedure leads to unbiased parameter estimation and accurate evaluation of uncertainties. We compare its performance to grid-based algorithms, showing that the efficiency in CPU time is similar to 100 times better for MCMC for a three-dimensional parameter space and increasing with the number of dimensions. We use GalMC to fit the stacked SEDs of two samples of Lyman alpha emitters (LAEs) at redshift z = 3.1. Our fit reveals that the typical LAE detected in the IRAC 3.6 mu m band has age = 0.67 [0.37-1.81] Gyr and stellar mass = 3.2 [2.5-4.2] x 10(9) M-circle dot, while the typical LAE not detected at 3.6 mu m has age = 0.06 [0.01-0.2] Gyr and stellar mass = 2 [1.1-3.4] x 10(8) M-circle dot. The SEDs of both stacks are consistent with the absence of dust. The data do not significantly prefer exponential with respect to constant star formation history. The stellar populations of these two samples are consistent with the previous study by Lai et al., with some differences due to the improved modeling of the stellar populations. A constraint on the metallicity of z = 3.1 LAEs from broadband photometry, requiring Z < Z(circle dot) at 95% confidence, is found here for the first time.
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    STACKED REST-FRAME ULTRAVIOLET SPECTRA OF Lyα-EMITTING AND CONTINUUM-SELECTED GALAXIES AT 2 < z < 3.5
    (2012) Berry, Michael; Gawiser, Eric; Guaita, Lucia; Padilla, Nelson; Treister, Ezequiel; Blanc, Guillermo A.; Ciardullo, Robin; Francke, Harold; Gronwall, Caryl
    We present properties of individual and composite rest-UV spectra of continuum-and narrowband-selected star-forming galaxies (SFGs) at a redshift of 2 < z < 3.5 discovered by the MUSYC collaboration in the Extended Chandra Deep Field-South. Among our sample of 81 UV-bright SFGs, 59 have R < 25.5, of which 32 have rest-frame equivalent widths of W-Ly alpha > 20 angstrom, the canonical limit to be classified as an Ly alpha-emitting galaxy. We divide our data set into subsamples based on properties that we are able to measure for each individual galaxy: Ly alpha equivalent width, rest-frame UV colors, and redshift. Among our subsample of galaxies with R < 25.5, those with rest frame W-Ly alpha > 20 angstrom have bluer UV continua, weaker low-ionization interstellar absorption lines, weaker C IV absorption, and stronger Si II* nebular emission than those with W-Ly alpha < 20 angstrom. We measure a velocity offset of Delta nu similar to 600 km s(-1) between Ly alpha emission and low-ionization absorption, which does not vary substantially among any of our subsamples. We find that the interstellar component, as opposed to the stellar component, dominates the high-ionization absorption line profiles. We find that the low-and high-ionization Si ionization states have similar kinematic properties, yet the low-ionization absorption is correlated with Ly alpha emission and the high-ionization absorption is not. These trends are consistent with outflowing neutral gas being in the form of neutral clouds embedded in ionized gas as previously suggested by Steidel et al. Moreover, our galaxies with bluer UV colors have stronger Ly alpha emission, weaker low-ionization absorption, and more prominent nebular emission line profiles. From a redshift of 2.7 < z < 3.5 to 2.0 < z < 2.7, our subsample of galaxies with W-Ly alpha < 20 angstrom shows no significant evolution in their physical properties or the nature of their outflows. Among our data set, UV-bright galaxies with W-Ly alpha > 20 angstrom exhibit weaker Ly alpha emission at lower redshifts, although we caution that this could be caused by spectroscopic confirmation of low Ly alpha equivalent width galaxies being harder at z similar to 3 than z similar to 2.
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    The One-hundred-deg2 DECam Imaging in Narrowbands (ODIN): Survey Design and Science Goals
    (2024) Lee, Kyoung-Soo; Gawiser, Eric; Park, Changbom; Yang, Yujin; Valdes, Francisco; Lang, Dustin; Ramakrishnan, Vandana; Moon, Byeongha; Firestone, Nicole; Appleby, Stephen; Artale, Maria Celeste; Andrews, Moira; Bauer, Franz; Benda, Barbara; Broussard, Adam; Chiang, Yi-Kuan; Ciardullo, Robin; Dey, Arjun; Farooq, Rameen; Gronwall, Caryl; Guaita, Lucia; Huang, Yun; Hwang, Ho Seong; Im, Sang Hyeok; Jeong, Woong-Seob; Karthikeyan, Shreya; Kim, Hwihyun; Kim, Seongjae; Kumar, Ankit; Nagaraj, Gautam R.; Nantais, Julie; Padilla, Nelson; Park, Jaehong; Pope, Alexandra; Popescu, Roxana; Schlegel, David; Seo, Eunsuk; Singh, Akriti; Song, Hyunmi; Troncoso, Paulina; Vivas, A. Katherina; Zabludoff, Ann; Zenteno, Alfredo
    We describe the survey design and science goals for One-hundred-deg(2) DECam Imaging in Narrowbands (ODIN), a NOIRLab survey using the Dark Energy Camera (DECam) to obtain deep (AB similar to 25.7) narrowband images over an unprecedented area of sky. The three custom-built narrowband filters, N419, N501, and N673, have central wavelengths of 419, 501, and 673 nm and respective FWHM of 7.5, 7.6, and 10.0 nm, corresponding to Ly alpha at z = 2.4, 3.1, and 4.5 and cosmic times of 2.8, 2.1, and 1.4 Gyr, respectively. When combined with even deeper, public broadband data from the Hyper Suprime-Cam, DECam, and in the future, the Legacy Survey of Space and Time, the ODIN narrowband images will enable the selection of over 100,000 Ly alpha-emitting (LAE) galaxies at these epochs. ODIN-selected LAEs will identify protoclusters as galaxy overdensities, and the deep narrowband images enable detection of highly extended Ly alpha blobs (LABs). Primary science goals include measuring the clustering strength and dark matter halo connection of LAEs, LABs, and protoclusters, and their respective relationship to filaments in the cosmic web. The three epochs allow for the redshift evolution of these properties to be determined during the period known as Cosmic Noon, where star formation was at its peak. The narrowband filter wavelengths are designed to enable interloper rejection and further scientific studies by revealing [O II] and [O III] at z = 0.34, Ly alpha and He II 1640 at z = 3.1, and Lyman continuum plus Ly alpha at z = 4.5. Ancillary science includes similar studies of the lower-redshift emission-line galaxy samples and investigations of nearby star-forming galaxies resolved into numerous [O III] and [S II] emitting regions.
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    TO STACK OR NOT TO STACK: SPECTRAL ENERGY DISTRIBUTION PROPERTIES OF Lyα-EMITTING GALAXIES AT z=2.1
    (2014) Vargas, Carlos J.; Bish, Hannah; Acquaviva, Viviana; Gawiser, Eric; Finkelstein, Steven L.; Ciardullo, Robin; Ashby, Matthew L. N.; Feldmeier, John; Ferguson, Henry; Gronwall, Caryl; Guaita, Lucia; Hagen, Alex; Koekemoer, Anton; Kurczynski, Peter; Newman, Jeffrey A.; Padilla, Nelson
    We use the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) GOODS-S multi-wavelength catalog to identify counterparts for 20 Ly alpha emitting (LAE) galaxies at z = 2.1. We build several types of stacked spectral energy distributions (SEDs) of these objects. We combine photometry to form average and median flux-stacked SEDs, and postage-stamp images to form average and median image-stacked SEDs. We also introduce scaled flux stacks that eliminate the influence of variation in overall brightness. We use the SED fitting code SpeedyMC to constrain the physical properties of individual objects and stacks. Our LAEs at z = 2.1 have stellar masses ranging from 2 x 10(7) M-circle dot to 8 x 10(9) M-circle dot (median = 3 x 10(8) M-circle dot), ages ranging from 4 Myr to 500 Myr (median = 100 Myr), and E(B - V) between 0.02 and 0.24 (median = 0.12). Although still low, this represents significantly more dust reddening than has been reported for LAEs at higher redshifts. We do not observe strong correlations between Ly alpha equivalent width (EW) and age or E(B - V). The Ly alpha radiative transfer (q) factors of our sample are predominantly close to one and do not correlate strongly with EW or E(B - V). The absence of strong correlations with EW or q implies that Ly alpha radiative transfer is highly anisotropic and/or prevents Ly alpha photons from scattering in dusty regions. The SED parameters of the flux stacks match the average and median values of the individual objects, with the flux-scaled median SED performing best with uncertainties reduced by a factor of two. Median image-stacked SEDs provide a poor representation of the median individual object, and none of the stacking methods capture the large dispersion of LAE properties.