Examinando por Autor "Egami, E."

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Acceso Abierto
ALMA 1.3 mm Survey of Lensed Submillimeter Galaxies Selected by Herschel: Discovery of Spatially Extended SMGs and Implications
(IOP Science Publishing, 2021-02-24) Sun, F.; Egami, E.; Rawle, T. D.; Walth, G. L.; Smail, I.; Dessauges-Zavadsky, M.; Pérez González, P. G.; Richard, J.; Combes, F.; Ebeling, H.; Pelló, R.; Werf, P. V.; Altieri, B.; Boone, F.; Cava, A.; Chapman, S. C.; Clément, B.; Finoguenov, A.; Nakajima, K.; Rujopakarn, W.; Schaerer, D.; Valtchanov, I.; Science and Technology Facilities Council (STFC); National Aeronautics and Space Administration (NASA); Sun, F. [0000-0002-4622-6617]; Rawle, T. D. [0000-0002-7028-5588]; Walth, G. L. [0000-0002-6313-6808]; Smail, I. [0000-0003-3037-257X]; Dessauges-Zavadsky, M. [0000-0003-0348-2917]; Pérez González, P. G. [0000-0003-4528-5639]; Richard, J. [0000-0001-5492-1049]; Combes, F. [0000-0003-2658-7893]; Ebeling, H. [0000-0001-8249-2739]; Pelló, R. [0000-0003-0858-6109]; Werf, P. V. [0000-0001-5434-5942]; Altieri, B. [0000-0003-3936-0284]; Cava, A. [0000-0002-4821-1275]; Finoguenov, A. [0000-0002-4606-5403]; Nakajima, K. [0000-0003-2965-5070]; Rujopakarn, W. [0000-0002-0303-499X]; Schaerer, D. [0000-0001-7144-7182]; Valtchanov, I. [0000-0001-9930-7886]
We present an ALMA 1.3 mm (Band 6) continuum survey of lensed submillimeter galaxies (SMGs) at z = 1.0 to ∼3.2 with an angular resolution of ∼0farcs2. These galaxies were uncovered by the Herschel Lensing Survey and feature exceptionally bright far-infrared continuum emission (Speak ≳ 90 mJy) owing to their lensing magnification. We detect 29 sources in 20 fields of massive galaxy clusters with ALMA. Using both the Spitzer/IRAC (3.6/4.5 μm) and ALMA data, we have successfully modeled the surface brightness profiles of 26 sources in the rest-frame near- and far-infrared. Similar to previous studies, we find the median dust-to-stellar continuum size ratio to be small (Re,dust/Re,star = 0.38 ± 0.14) for the observed SMGs, indicating that star formation is centrally concentrated. This is, however, not the case for two spatially extended main-sequence SMGs with a low surface brightness at 1.3 mm (≲0.1 mJy arcsec−2), in which the star formation is distributed over the entire galaxy (Re,dust/Re,star > 1). As a whole, our SMG sample shows a tight anticorrelation between (Re,dust/Re,star) and far-infrared surface brightness (ΣIR) over a factor of ≃1000 in ΣIR. This indicates that SMGs with less vigorous star formation (i.e., lower ΣIR) lack central starburst and are likely to retain a broader spatial distribution of star formation over the whole galaxies (i.e., larger Re,dust/Re,star). The same trend can be reproduced with cosmological simulations as a result of central starburst and potentially subsequent "inside-out" quenching, which likely accounts for the emergence of compact quiescent galaxies at z ∼ 2.
Restringido
Mid-IR cosmological spectrophotometric surveys from space: Measuring AGN and star formation at the cosmic noon with a SPICA-like mission
(Cambridge University Press, 2021-04-23) Spignoglio, L.; Mordini, S.; Fernández Ontiveros, J. A.; Alonso Herrero, A.; Armus, L.; Bisigello, L.; Calura, F.; Carrera, F. J.; Cooray, A.; Dannerbauer, H.; Decarli, R.; Egami, E.; Elbaz, D.; Franceschini, A.; González Alfonso, E.; Graziani, L.; Gruppioni, C.; Hatziminaoglou, Evanthia; Kaneda, H.; Kohno, K.; Labiano, Á.; Magdis, Georgios E.; Malkan, M. A.; Matsuhara, H.; Nagao, T.; Naylor, D.; Pereira Santaella, M.; Pozzi, F.; Rodighiero, G.; Roelfsema, P.; Serjeant, S.; Vignali, C.; Wang, L.; Yamada, T.; Agenzia Spaziale Italiana (ASI); Agencia Estatal de Investigación (AEI); Comunidad de Madrid; Spignoglio, L. [0000-0001-8840-1551]; Fernández Ontiveros, J. A. [0000-0001-9490-899X]; Gruppioni, C. [0000-0002-5836-4056]; Graziani, L. [0000-0002-9231-1505]; Unidad de Excelencia Científica María de Maeztu Instituto de Astrofísica de Cantabria, MDM-2017-0765; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We use the SPace Infrared telescope for Cosmology and Astrophysics (SPICA) project as a template to demonstrate how deep spectrophotometric surveys covering large cosmological volumes over extended fields (1– ) with a mid-IR imaging spectrometer (17– ) in conjunction with deep photometry with a far-IR camera, at wavelengths which are not affected by dust extinction can answer the most crucial questions in current galaxy evolution studies. A SPICA-like mission will be able for the first time to provide an unobscured three-dimensional (3D, i.e. x, y, and redshift z) view of galaxy evolution back to an age of the universe of less than 2 Gyrs, in the mid-IR rest frame. This survey strategy will produce a full census of the Star Formation Rate (SFR) in the universe, using polycyclic aromatic hydrocarbons (PAH) bands and fine-structure ionic lines, reaching the characteristic knee of the galaxy luminosity function, where the bulk of the population is distributed, at any redshift up to . Deep follow-up pointed spectroscopic observations with grating spectrometers onboard the satellite, across the full IR spectral range (17– ), would simultaneously measure Black Hole Accretion Rate (BHAR), from high-ionisation fine-structure lines, and SFR, from PAH and low- to mid-ionisation lines in thousands of galaxies from solar to low metallicities, down to the knee of their luminosity functions. The analysis of the resulting atlas of IR spectra will reveal the physical processes at play in evolving galaxies across cosmic time, especially its heavily dust-embedded phase during the activity peak at the cosmic noon ( –3), through IR emission lines and features that are insensitive to the dust obscuration.
Restringido
Molecular clouds in the Cosmic Snake normal star-forming galaxy 8 billion years ago
(Nature Research Journals, 2019-09-16) Dessauges Zavadsky, M.; Richard, J.; Combes, F.; Schaerer, D.; Rujopakarn, W.; Mayer, L.; Cava, A.; Boone, F.; Egami, E.; Kneib, J. P.; Pérez González, P. G.; Pfenniger, D.; Rawle, T. D.; Teyssier, R.; Van der Werf, P. P.; Copyright © 2019, The Author(s), under exclusive licence to Springer Nature Limited; European Research Council (ERC); Ministerio de Economía y Competitividad (MINECO); Combes, F. [0000-0003-2658-7893]; Van der Werf, P. [0000-0001-5434-5942]; Kneib, J. P. [0000-0002-4616-4989]; Pfenniger, D. [0000-0002-0980-3622]; Rawle, T. [0000-0002-7028-5588]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The cold molecular gas in contemporary galaxies is structured in discrete cloud complexes. These giant molecular clouds (GMCs), with 10(4)-10(7) solar masses (M-circle dot) and radii of 5-100 parsecs, are the seeds of star formation(1). Highlighting the molecular gas structure at such small scales in distant galaxies is observationally challenging. Only a handful of molecular clouds were reported in two extreme submillimetre galaxies at high redshift(2-4). Here we search for GMCs in a typical Milky Way progenitor at z = 1.036. Using the Atacama Large Millimeter/submillimeter Array (ALMA), we mapped the CO(4-3) emission of this gravitationally lensed galaxy at high resolution, reading down to 30 parsecs, which is comparable to the resolution of CO observations of nearby galaxies(5). We identify 17 molecular clouds, characterized by masses, surface densities and supersonic turbulence all of which are 10-100 times higher than present-day analogues. These properties question the universality of GMCs(6) and suggest that GMCs inherit their properties from ambient interstellar medium. The measured cloud gas masses are similar to the masses of stellar clumps seen in the galaxy in comparable numbers(7). This corroborates the formation of molecular clouds by fragmentation of distant turbulent galactic gas disks(8,9), which then turn into stellar clumps ubiquitously observed in galaxies at 'cosmic noon' (ref.(10).