. | . |
Cosmic lantern could help us further understand the fate of the Universe by Staff Writers Portsmouth UK (SPX) Dec 26, 2017
New research has provided a deeper insight into emission line galaxies, used in several ongoing and upcoming surveys, to help us further understand the composition and fate of the Universe. The quest to determine the nature of both dark matter and dark energy has led scientists to adopt new tracers of the large-scale structure of the Universe, such as emission line galaxies. These galaxies present strong emission lines from the gas heated up by newly formed stars. Lead author of the study, Dr Violeta Gonzalez-Perez from the University's Institute of Cosmology and Gravitation, said: "Galaxies are cosmic lanterns that show small patches of cosmic history, informing us of the changes in the space-time fabric of the Universe. The strong formation of new stars in galaxies leave a characteristic imprint in their spectra that allows for a precise determination of their distance. "Moreover, as young stars are very bright, galaxies with a strong star formation can be visible further back in cosmic time. These are the two characteristics that make emission line galaxies excellent cosmological tracers for a long time span." However, current emission line galaxy samples are small and their characteristics are not well understood. Computational modelling is the only way to attempt to understand all the processes involved in the formation and evolution of these galaxies. Astronomers from the the world-leading Institute of Cosmology and Gravitation (ICG) explored the characteristics of emission line galaxies through experiments on DiRAC's (Distributed Research utilising Advanced Computing) national supercomputing facility at Durham University. The computational experiments were concentrated around the time when the Universe went from being matter dominated to becoming dark energy dominated as it is now. They found that most emission line galaxies live at the centres of gravitational potential wells, with masses equivalent to eleven billion of our suns. Current numerical models of formation and evolution of galaxies also show that emission line galaxies trace the underlying gravitational potentials in a different way to galaxies selected by their stellar mass. They then compared their results with the expectations from the SDSS-IV/eBOSS surveys and Dark Energy Spectroscopic Instrument (DESI). Both surveys aim to measure the effect of dark energy on the expansion of the Universe. Dr Gonzalez-Perez said: "This comparison will improve our understanding of galaxy formation and evolution and allow scientists to benefit from a more realistic model for the mechanisms that produce emission line galaxies." Next summer, the SDSS-IV/eBOSS survey is expected to have the first cosmological results from these tracers. In the coming years, the Dark Energy Survey Instrument (DESI) will expand this usage of emission line galaxies as cosmological tracers. The DESI will see their first light in 2019 and it will measure the spectra of 35 million galaxies, which is eight times more than the current SDSS has proved. In 2021, Euclid will start collecting spectra for 50 million sources, solely focusing on emission line galaxies. The ICG is involved in both surveys. The study, which is published in the Monthly Notices of the Royal Astronomical Society (published by Oxford University Press), involved researchers from the Universities of Portsmouth and Durham (UK), the Max Planck Institute for Extraterrestrial Physics (Germany), the Pontifical Catholic University of Chile and Centro de Estudios de Fisica del Cosmos de Aragon (Spain).
Berkeley CA (SPX) Dec 19, 2017 Seeing is believing, or so the saying goes. And in some cases, a world of make-believe can help you realize what you're actually seeing, too. Scientists are creating simulated universes, for example - complete with dark matter mock-ups, computer-generated galaxies, quasi quasars, and pseudo supernovae - to better understand real-world observations. Their aim is to envision how new Ea ... read more Related Links University of Portsmouth's Understanding Time and Space
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |