In the galaxies, size does not matter
In the galaxies, size does not matter
The early universe has always aroused interest among scientists, especially at times such as when it became transparent to ultraviolet light: it is interesting and we do not know all the details of that time, called reionization and that occurred when the thick fog of hydrogen gas it dispersed.Thanks to the recent discovery of more than 250 galaxies that were already there when the universe was 600-900 million years ago it was possible to date more accurately when that era of reionization ended, because its light, extremely dim, has led us to those moments . "The weakest galaxies detected in these observations are weaker than any other object discovered in Hubble's deep-field observations," says Johan Richard, of the Lyon Observatory (France) and co-author of the article that includes the research.Image 1: MACS galaxy cluster J0416.1-2403, one of those analyzed in this investigation to study the reionization period. Credits: NASA, ESA and the HST Frontier Fields team (STScI).After studying this weak light from the new galaxies, the team determined for the first time that the smallest galaxies may have caused the universe to be transparent. "If we take into account only the contributions of the bright and massive galaxies, we saw that they were not enough for the Universe to re-initiate, a more abundant population of dwarf dwarf galaxies was needed," Hakim Atek explains. Federal Polytechnic School of Lausanne (Switzerland) and main author of the article that gathers the investigation.Image 2: Cluster of galaxies MACSJ0717.5 + 3745 obtained from the Frontier Fields program and analyzed by the team led by H. Atek. Credits: NASA, ESA and the HST Frontier Fields team (STScI).To reach these conclusions, the team used images produced by a gravitational lens in three galaxy clusters that are part of the program Frontier Fields of the Hubble Space Telescope. "The clusters in the Frontier Fields act like powerful natural telescopes and show us these dim dwarf galaxies that would otherwise be invisible," explains Jean-Paul Kneib, of the Federal Polytechnic School of Lausanne (Switzerland) and co-author of the article exposes the investigation.Image 3: Cluster of Abell 2744 galaxies, nicknamed Pandora. It was the first of the six objectives of the Frontier Fields program that was analyzed in this investigation. Credits: NASA, ESA and the HST Frontier Fields team (STScI).With this, the time of reionization is estimated to have ended around 700 million years after the Big Bang, and for the first time they know how this phenomenon could happen that made light in the universe free to spread.If you like the reionized universe and the dwarf galaxies, Do not forget to vote for me Awards Logbooks 2015!The article that collects the research has been published in the journal Astrophysical Journal under the title "Are Ultra-faint Galaxies at z = 6-8 Responsible for Cosmic Reionization? Combined Constraints from the Hubble Frontier Fields Clusters And Parallels", by H. Atek et al.The team that has carried out the research consists of Hakim Atek (Laboratoire d'Astrophysique, Ecole Polytechnique Fédérale de Lausanne, Suuiza, Department of Astronomy, Yale University, United States), Johan Richard (CRAL, Observatoire de Lyon, France) , Mathilde Jauzac (Institute for Computational Cosmology, Durham University, United Kingdom, Astrophysics and Cosmology Research Unit, University of KwaZulu-Natal, South Africa), Jean-Paul Kneib (Laboratoire d'Astrophysique, Ecole Polytechnique Fédérale de Lausanne, Switzerland, Aix Marseille Université, CNRS, LAM UMR 7326, France), Priyamvada Natarajan (Department of Astronomy, Yale University, United States), Marceau Limousin (Aix Marseille Université, CNRS, LAM UMR 7326, France), Daniel Schaerer (Observatoire de Genève, Suzia; CNRS, IRAP, France), Eric Jullo (Aix Marseille Université, CNRS, LAM UMR 7326, France), Harald Ebeling (Institute for Astronomy, University of Hawaii, United States), Eiichi Egami (Steward Observatory, University of Arizona, United States) and Benjamin Clement (CRAL, Observatoire de Lyon, France).Images 1, 2 and 3 have been taken by the Hubble Space Telescope through the ACS (Advanced Camera for Surveys) and WFC3 (Wide Field Camera 3) instruments in a composition with the following filters:B-band optical filter (435 nm) of the ACS instrumentV-band optical filter (606 nm) of the ACS instrumentInfrared filter in band I (814 nm) of the ACS instrumentInfrared filter in Y band (1.05 um) of the WFC3 instrumentInfrared J-band filter (1.25 um) of the WFC3 instrumentH band infrared filter (1.40 um) of the WFC3 instrumentW band infrared filter (1.60 um) of the WFC3 instrumentScientific article:- Are Ultra-faint Galaxies at z = 6-8 Responsible for Cosmic Reionization? Combined Constraints from the Hubble Frontier Fields Clusters And Parallels (H. Atek et al., ArXiv: 1509.06764)References:-Are you interested? Follow me also in Twitter.
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