Examinando por Autor "Schaerer, D."

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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
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).
Restringido
The discovery of the most UV–Ly α luminous star-forming galaxy: a young, dust- and metal-poor starburst with QSO-like luminosities
(Oxford Academics: Oxford University Press, 2020-09-16) Marques Chaves, R.; Álvarez Márquez, J.; Colina, L.; Pérez Fournon, I.; Schaerer, D.; Dalla Vecchia, C.; Hashimoto, T.; Jiménez Ángel, C.; Shu, Y.; Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Shu, Y. [0000-0002-9063-698X]; Dalla Vecchia, C. [0000-0002-2620-7056]; Marqués Chaves, R. [0000-0001-8442-1846]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We report the discovery of BOSS-EUVLG1 at z = 2.469, by far the most luminous, almost un-obscured star-forming galaxy known at any redshift. First classified as a QSO within the Baryon Oscillation Spectroscopic Survey, follow-up observations with the Gran Telescopio Canarias reveal that its large luminosity, M-UV similar or equal to -24.40 and log(L-Ly alpha/erg s(-1)) similar or equal to 44.0, is due to an intense burst of star formation, and not to an active galactic nucleus or gravitational lensing. BOSS-EUVLG1 is a compact (r(eff) similar or equal to 1.2 kpc), young (4-5 Myr) starburst with a stellar mass log(M-*/M-circle dot) = 10.0 +/- 0.1 and a prodigious star formation rate of similar or equal to 1000 M-circle dot yr(-1). However, it is metal- and dust-poor [12+ log(O/H) = 8.13 +/- 0.19, E(B - V) similar or equal to 0.07, log(L-IR/L-UV) < -1.2], indicating that we are witnessing the very early phase of an intense starburst that has had no time to enrich the ISM. BOSS-EUVLG1 might represent a short-lived (<100 Myr), yet important phase of star-forming galaxies at high redshift that has been missed in previous surveys. Within a galaxy evolutionary scheme, BOSS-EUVLG1 could likely represent the very initial phases in the evolution of massive quiescent galaxies, even before the dusty star-forming phase.
Restringido
The UV-brightest Lyman continuum emitting star-forming galaxy
(Oxford Academics: Oxford University Press, 2021-07-30) Marques Chaves, R.; Schaerer, D.; Álvarez Márquez, J.; Colina, L.; Dessauges-Zavadsky, M.; Pérez Fournon, I.; Saldana López, A.; Verhamme, A.; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We report the discovery of J0121+0025, an extremely luminous and young star-forming galaxy (MUV = −24.11, log[LLyα/erg s−1]=43.8⁠) at z = 3.244 showing copious Lyman continuum (LyC) leakage (⁠fesc,abs≈40 per cent⁠). High signal-to-noise ratio rest-frame UV spectroscopy with the Gran Telescopio Canarias reveals a high significance (7.9σ) emission below the Lyman limit (<912 Å), with a flux density level f900 = 0.78 ± 0.10μJy, and strong P-Cygni in wind lines of O VI 1033 Å, N V 1240 Å, and C IV 1550 Å that are indicative of a young age of the starburst (<10 Myr). The spectrum is rich in stellar photospheric features, for which a significant contribution of an AGN at these wavelengths is ruled out. Low-ionization interstellar medium (ISM) absorption lines are also detected, but are weak (⁠EW0≃1 Å) and show large residual intensities, suggesting a clumpy geometry of the gas with a non-unity covering fraction or a highly ionized ISM. The contribution of a foreground and AGN contamination to the LyC signal is unlikely. Deep optical to Spitzer/IRAC 4.5 μm imaging show that the spectral energy distribution of J0121+0025 is dominated by the emission of the young starburst, with log(⁠Mburst⋆/M⊙)=9.9±0.1 and SFR=981±232 M⊙ yr−1. J0121+0025 is the most powerful LyC emitter known among the star-forming galaxy population. The discovery of such luminous and young starburst leaking LyC radiation suggests that a significant fraction of LyC photons can escape in sources with a wide range of UV luminosities and are not restricted to the faintest ones as previously thought. These findings might shed further light on the role of luminous starbursts to the cosmic reionization.