Examinando por Autor "Kneissl R."

Mostrando 1 - 2 de 2
  • No hay miniatura disponible
    Ítem
    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.
  • No hay miniatura disponible
    Ítem
    The ALMA Frontier Fields Survey: VI. Lensing-corrected 1.1 mm number counts in Abell 2744, MACSJ0416.1-2403, MACSJ1149.5+2223, Abell 370, and Abell S1063
    (EDP Sciences, 2023) Muñoz Arancibia A.M.; González-López J.; Ibar E.; Bauer F.E; Anguita T.; Aravena M.; Demarco R.; Kneissl R.; Koekemoer A.M.; Troncoso-Iribarren P.; Zitrin A.
    Context. Probing the faint end of the number counts at millimeter wavelengths is important in order to identify the origin of the extragalactic background light in this regime. Aided by strong gravitational lensing, ALMA observations toward massive galaxy clusters have opened a window to probe this origin, allowing us to resolve sub-milliJansky dusty star-forming galaxies. Aims. We aim to derive number counts at 1.1 mm down to flux densities fainter than 0.1 mJy based on ALMA observations toward five Hubble Frontier Fields (FF) galaxy clusters, following a statistical approach to correct for lensing effects. Methods. We created a source catalog that includes ALMA 1.1 mm continuum detections around two new FF galaxy clusters, together with the sources previously detected around three FF galaxy clusters, making a total of 29 detected sources down to a 4.5σ significance. ALMA 1.1 mm mosaics used for our source extraction covered the inner ≈2′ × 2′; FF regions, reached rms depths of ≈55 - 71μJy beam-1, and had synthesized beam sizes from ≈0″.5 - 1″.5 (natural weighting). We derived source intrinsic flux densities using public lensing models. We folded the uncertainties in both magnifications and source redshifts into the number counts through Monte Carlo simulations. Results. Using the combination of all cluster fields, we derive cumulative number counts over two orders of magnitude down to ≈0.01 mJy after correction for lensing effects. Cosmic variance estimates are all exceeded by uncertainties in our median combined cumulative counts that come from both our Monte Carlo simulations and Poisson statistics. Our number counts agree at a 1σ level with our previous estimates using ALMA observations of the first three FFs, exhibiting a similar flattening at faint flux densities. They are also consistent to 1σ with most recent ALMA estimates and galaxy evolution models. However, below ≈0.1 mJy, our cumulative number counts are lower by ≈0.4 dex compared to two deep ALMA studies (namely one that probes several blank fields plus one lensed galaxy cluster, and the initial ALMA Spectroscopic Survey in the Hubble Ultra Deep Field, ASPECS-Pilot), while remaining consistent with the ASPECS Large Program (ASPECS-LP) within 1σ. Importantly, the flattening found for our cumulative counts at ≲0.1 mJy also extends further to ≈0.01 mJy, that is, ≈0.4 dex fainter than ASPECS-LP, and remains in agreement with extrapolations of their number counts down to this flux limit. We find a median contribution to the extragalactic background light (EBL) of 14-8+12 Jy deg-2 resolved in our demagnified sources down to ≈0.01 mJy, representing 75 - 86% of Planck-derived extragalactic EBL estimates at 1.1 mm. Conclusions. We estimate cumulative 1.1 mm number counts down to ≈0.01 mJy along the line of sight of five galaxy clusters that benefit from having rich deep multiwavelength data. They bring further support to the flattening of the number counts reported previously by us and ASPECS-LP, which has been interpreted by a recent galaxy evolution model as a measurement of the "knee"of the infrared luminosity function at high redshift. Our estimates of the contribution to the EBL associated with 1.1 mm galaxies in the FFs suggest that we may be resolving most of the EBL at this wavelength down to ≈0.01 mJy. © M. Grandin et al., Published by EDP Sciences 2023M. Grandin et al., Published by EDP Sciences 2023