Examinando por Autor "Messias H."

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    Molecular gas, dust, and star formation in galaxies: I. Dust properties and scalings in ~ 1600 nearby galaxies
    (EDP Sciences, 2017-06) Orellana G.; Nagar N.M.; Elbaz D.; Calderón-Castillo P.; Leiton R.; Ibar E.; Magnelli B.; Daddi E.; Messias H.; Cerulo P.; Slater R.
    Context. Dust and its emission is increasingly being used to constrain the evolutionary stage of a galaxy. A comprehensive characterization of dust, best achieved in nearby bright galaxies, is thus a highly useful resource. Aims. We aim to characterize the relationship between dust properties (mass, luminosity, and temperature) and their relationships with galaxy-wide properties (stellar, atomic, and molecular gas mass, and star formation mode). We also aim to provide equations to accurately estimate dust properties from limited observational datasets. Methods. We assemble a sample of 1630 nearby (z < 0.1) galaxies - over a large range of stellar masses (M∗), star formation rates (SFR) and specific star formation rates (sSFR = SFR/M∗) - for which comprehensive and uniform multi-wavelength observations are available from WISE, IRAS, Planck, and/or SCUBA. The characterization of dust emission comes from spectral energy distribution (SED) fitting using Draine & Li (2007, ApJ, 657, 810) dust models, which we parametrize using two components (warm at 45-70 K and cold at 18-31 K). The subsample of these galaxies with global measurements of CO and/or HI are used to explore the molecular and/or atomic gas content of the galaxies. Results. The total infrared luminosity (LIR), dust mass (Mdust), and dust temperature of the cold component (Tcold) form a plane that we refer to as the dust plane. A galaxy's sSFR drives its position on the dust plane: starburst (high sSFR) galaxies show higher LIR, Mdust, and Tcold compared to main sequence (typical sSFR) and passive galaxies (low sSFR). Starburst galaxies also show higher specific dust masses (Mdust/M∗) and specific gas masses (Mgas/M∗). We confirm earlier findings of an anti-correlation between the dust to stellar mass ratio and M∗. We also find different anti-correlations depending on sSFR; the anti-correlation becomes stronger as the sSFR increases, with the spread due to different cold dust temperatures. The dust mass is more closely correlated with the total gas mass (atomic plus molecular) than with the individual atomic and molecular gas masses. Our comprehensive multiwavelength data allows us to define several equations to accurately estimate LIR, Mdust, and Tcold from one or two monochromatic luminosities in the infrared and/or sub-millimeter. Conclusions. It is possible to estimate the dust mass and infrared luminosity from a single monochromatic luminosity within the Rayleigh-Jeans tail of the dust emission, with errors of 0.12 and 0.20 dex, respectively. These errors are reduced to 0.05 and 0.10 dex, respectively, if the dust temperature of the cold component is used. The dust mass is better correlated with the total ISM mass (MISM ∞ Mdust0.7). For galaxies with stellar masses 8.5 < log(M∗/M⊙) < 11.9, the conversion factor between the single monochromatic luminosity at 850 μm and the total ISM mass (α850 μm) shows a large scatter (rms = 0.29 dex) and a weak correlation with the LIR. The star formation mode of a galaxy shows a correlation with both the gas mass and dust mass: the dustiest (high Mdust /M∗) galaxies are gas-rich and show the highest SFRs. © ESO, 2017.
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    The ALMA Frontier Fields Survey: I. 1.1 mm continuum detections in Abell 2744, MACS J0416.1-2403 and MACS J1149.5+2223
    (EDP Sciences, 2017) González-López J.; Bauer F.E.; Romero-Cañizales C.; Kneissl R.; Villard E.; Carvajal R.; Kim S.; Laporte N.; Anguita T.; Aravena M.; Bouwens R.J.; Bradley L.; Carrasco M.; Demarco R.; Ford H.; Ibar E.; Infante L.; Messias H.; Muñoz Arancibia A.M.; Nagar N.; Padilla N.; Treister E.; Troncoso P.; Zitrin A.
    Context. Dusty star-forming galaxies are among the most prodigious systems at high redshift (z> 1), characterized by high starformation rates and huge dust reservoirs. The bright end of this population has been well characterized in recent years, but considerable uncertainties remain for fainter dusty star-forming galaxies, which are responsible for the bulk of star formation at high redshift and thus play a key role in galaxy growth and evolution. Aims. In this first paper of our series, we describe our methods for finding high redshift faint dusty galaxies using millimeter observations with ALMA. Methods. We obtained ALMA 1.1mm mosaic images for three strong-lensing galaxy clusters from the Frontier Fields Survey, which constitute some of the best studied gravitational lenses to date. The 20 20 mosaics overlap with the deep HST WFC3/IR footprints and encompass the high magnification regions of each cluster for maximum intrinsic source sensitivity. The combination of extremely high ALMA sensitivity and the magnification power of these clusters allows us to systematically probe the sub-mJy population of dusty star-forming galaxies over a large surveyed area. Results. We present a description of the reduction and analysis of the ALMA continuum observations for the galaxy clusters Abell 2744 (z = 0:308), MACS J0416.1-2403 (z = 0:396) and MACS J1149.5+2223 (z = 0:543), for which we reach observed rms sensitivities of 55, 59 and 71 Jy beam-1 respectively.We detect 12 dusty star-forming galaxies at S=N 5:0 across the three clusters, all of them presenting coincidence with near-infrared detected counterparts in the HST images. None of the sources fall close to the lensing caustics, thus they are not strongly lensed. The observed 1.1mm flux densities for the total sample of galaxies range from 0.41 to 2.82 mJy, with observed effective radii spanning .00:005 to 00:037 00:021. The lensing-corrected sizes of the detected sources appear to be in the same range as those measured in brighter samples, albeit with possibly larger dispersion. © ESO 2016.