Evolutionary Map of the Universe, or EMU, is a large project which will use the new ASKAP telescope to make a census of radio sources in the sky. EMU is expected to detect about 70 million radio sources.[1] Most of these radio sources will be galaxies millions of light years away, many containing massive black holes, and some of the signals detected will have been sent less than half a billion years after the Big Bang, which created the universe 13.7 billion years ago. Unlike the NVSS, which mainly detected active galactic nuclei, the greater sensitivity of EMU means that about half the galaxies detected will be star-forming galaxies.
EMU's primary science driver is to try to understand how the stars and galaxies were first formed, and how they evolved to their present state. The census of 70 million galaxies detected by EMU will represent galaxies in all their different stages of evolution, so that they can be placed in sequence, enabling the study of how their properties change as they evolve. EMU will be able to probe star forming galaxies up to a redshift of about 1, active galactic nuclei to the edge of the observable universe, and will undoubtedly uncover new classes of object.
EMU was chosen (with WALLABY) as one of the two highest-ranked proposals for ASKAP from an initial field of 39 expressions of interest.[2] EMU is an international project, and the EMU team consists of over 400 astronomers in 21 countries.
In addition to planning and conducting the radio survey itself, the EMU project also includes
Key Science Projects, which will deliver the key science goals from EMU. These include Galaxy Evolution, Cosmology, Galaxy Clusters, the Galactic Plane, and Radio Stars.[3]
Development Projects, which are developing and optimising the tools needed to generate the science from the EMU data. These include source extraction,[4] cross-identification with multi-wavelength catalogues,[5] and redshift determination. One such development project has resulted in the creation of the Radio Galaxy Zoo citizen science project.[6]
The EMU project was proposed in 2009 by a team led by Ray Norris. It was ranked by ASKAP in the top two of ten Survey Science projects, with Norris the Project Leader, and A. Hopkins and N. Seymour as Project Scientists. Seymour stepped down in 2018, and Norris stepped down in 2020. Currently, Andrew Hopkins is the Project Leader. The EMU team now has over 400 members.
Technical Overviewedit
EMU is a radio sky survey project which will use the new ASKAP telescope to make a deep (~10 microJy rms) radio continuum survey covering the entire Southern Sky as far north as declination +30°. It will have about 40 times the sensitivity, and six times the resolution, of the NVSS”, and will also be more sensitive to extended diffuse emission, because of the short baselines built into the ASKAP array.
EMU will survey the entire sky visible from the ASKAP telescope in 30 square degree fields. Each field will be surveyed over the 300 MHz band from about 1110 to 1410 MHz, in 1 MHz channels, delivering both spectral shapes and, through the POSSUM[7] project, all four Stokes parameters and rotation measures. The data will be processed in near-real-time by the ASKAP pipeline processor. After the processed data have been approved for quality control by the EMU team, they will be placed in the public domain. The radio components will then be grouped into radio sources, and where possible cross-matched with other multiwavelength data. They will then be placed into the EMU value-added catalogue (EVACAT) which will be available only to members of the EMU team for some proprietary period before being released into the public domain.
TimelineThe EMU project has five phases (dates are notional, and depend on construction and commissioning progress)edit
EMU Phase 1: Design Study (2008-2015): The EMU design study examined issues such as simulating the performance of the phased-array-feed, developing high-dynamic-range imaging algorithms, source extraction and identification, etc. It also conducts pilot science experiments on fields such as the ATLAS, SCORPIO, and COSMOS fields, to guide the ultimate EMU science.
EMU Phase 2: BETA Commissioning (2013-2015) The EMU team contributed enthusiastically to the ASKAP Commissioning process, including using the 6-antenna Boolardy Test Array (BETA) to make the first observations, debugging the telescope and its processing.
EMU Phase 3: ASKAP-12 Commissioning: In 2016, a science-ready ASKAP ("ASKAP-12") was delivered with 12 of the 36 antennas equipped with ADE ("MkII") PAFs (in addition to the six antennas equipped with BETA PAFs, which are not expected to be used). A significant period of commissioning and debugging the instrument ensued.
EMU Phase 4: Early Science: The first survey science observations will be made with the ASKAP-12 array, starting in early 2016. A number of science projects were observed ed, resulting in a number of journal papers.. During this period the additional antennas were progressively equipped with PAFs.
EMU Phase 5: Pilot Surveys. The first EMU Pilot Field was observed in 2019–2020, and a paper presenting the main results was published.[8] Several science papers have been published, including the discovery of Odd Radio Circles.
EMU Phase 5: Full Survey Science: (2022). The EMU survey observations themselves are expected to take up to 5 years of telescope time. It is hoped eventually that WALLABY data will be able to be combined with EMU data to obtain an even more sensitive uimage of the sky.
^Gaensler, B. et al., Survey Science with ASKAP: Polarization Sky Survey of the Universe's Magnetism (POSSUM), Bulletin of the American Astronomical Society (2010), Vol. 42, p.515. http://adsabs.harvard.edu/abs/2010AAS...21547013G
evolutionary, universe, large, project, which, will, askap, telescope, make, census, radio, sources, expected, detect, about, million, radio, sources, most, these, radio, sources, will, galaxies, millions, light, years, away, many, containing, massive, black, . Evolutionary Map of the Universe or EMU is a large project which will use the new ASKAP telescope to make a census of radio sources in the sky EMU is expected to detect about 70 million radio sources 1 Most of these radio sources will be galaxies millions of light years away many containing massive black holes and some of the signals detected will have been sent less than half a billion years after the Big Bang which created the universe 13 7 billion years ago Unlike the NVSS which mainly detected active galactic nuclei the greater sensitivity of EMU means that about half the galaxies detected will be star forming galaxies Australian Square Kilometre Array Pathfinder ASKAP radio telescope arrayEMU s primary science driver is to try to understand how the stars and galaxies were first formed and how they evolved to their present state The census of 70 million galaxies detected by EMU will represent galaxies in all their different stages of evolution so that they can be placed in sequence enabling the study of how their properties change as they evolve EMU will be able to probe star forming galaxies up to a redshift of about 1 active galactic nuclei to the edge of the observable universe and will undoubtedly uncover new classes of object EMU was chosen with WALLABY as one of the two highest ranked proposals for ASKAP from an initial field of 39 expressions of interest 2 EMU is an international project and the EMU team consists of over 400 astronomers in 21 countries In addition to planning and conducting the radio survey itself the EMU project also includes Key Science Projects which will deliver the key science goals from EMU These include Galaxy Evolution Cosmology Galaxy Clusters the Galactic Plane and Radio Stars 3 Development Projects which are developing and optimising the tools needed to generate the science from the EMU data These include source extraction 4 cross identification with multi wavelength catalogues 5 and redshift determination One such development project has resulted in the creation of the Radio Galaxy Zoo citizen science project 6 Collaboration Projects which develop and maintain collaborations with other large survey projects such as Meerkat Mightee MWA GLEAM LOFAR SkyMapper WISE and eRosita The WTF project which will mine the EMU data for unexpected discoveries that are not included in the science goals Contents 1 History 2 Technical Overview 3 TimelineThe EMU project has five phases dates are notional and depend on construction and commissioning progress 4 References 5 External linksHistory editThe EMU project was proposed in 2009 by a team led by Ray Norris It was ranked by ASKAP in the top two of ten Survey Science projects with Norris the Project Leader and A Hopkins and N Seymour as Project Scientists Seymour stepped down in 2018 and Norris stepped down in 2020 Currently Andrew Hopkins is the Project Leader The EMU team now has over 400 members Technical Overview editEMU is a radio sky survey project which will use the new ASKAP telescope to make a deep 10 microJy rms radio continuum survey covering the entire Southern Sky as far north as declination 30 It will have about 40 times the sensitivity and six times the resolution of the NVSS and will also be more sensitive to extended diffuse emission because of the short baselines built into the ASKAP array EMU will survey the entire sky visible from the ASKAP telescope in 30 square degree fields Each field will be surveyed over the 300 MHz band from about 1110 to 1410 MHz in 1 MHz channels delivering both spectral shapes and through the POSSUM 7 project all four Stokes parameters and rotation measures The data will be processed in near real time by the ASKAP pipeline processor After the processed data have been approved for quality control by the EMU team they will be placed in the public domain The radio components will then be grouped into radio sources and where possible cross matched with other multiwavelength data They will then be placed into the EMU value added catalogue EVACAT which will be available only to members of the EMU team for some proprietary period before being released into the public domain TimelineThe EMU project has five phases dates are notional and depend on construction and commissioning progress editEMU Phase 1 Design Study 2008 2015 The EMU design study examined issues such as simulating the performance of the phased array feed developing high dynamic range imaging algorithms source extraction and identification etc It also conducts pilot science experiments on fields such as the ATLAS SCORPIO and COSMOS fields to guide the ultimate EMU science EMU Phase 2 BETA Commissioning 2013 2015 The EMU team contributed enthusiastically to the ASKAP Commissioning process including using the 6 antenna Boolardy Test Array BETA to make the first observations debugging the telescope and its processing EMU Phase 3 ASKAP 12 Commissioning In 2016 a science ready ASKAP ASKAP 12 was delivered with 12 of the 36 antennas equipped with ADE MkII PAFs in addition to the six antennas equipped with BETA PAFs which are not expected to be used A significant period of commissioning and debugging the instrument ensued EMU Phase 4 Early Science The first survey science observations will be made with the ASKAP 12 array starting in early 2016 A number of science projects were observed ed resulting in a number of journal papers During this period the additional antennas were progressively equipped with PAFs EMU Phase 5 Pilot Surveys The first EMU Pilot Field was observed in 2019 2020 and a paper presenting the main results was published 8 Several science papers have been published including the discovery of Odd Radio Circles EMU Phase 5 Full Survey Science 2022 The EMU survey observations themselves are expected to take up to 5 years of telescope time It is hoped eventually that WALLABY data will be able to be combined with EMU data to obtain an even more sensitive uimage of the sky References edit Norris R P et al EMU Evolutionary Map of the Universe PASA 2015 Volume 28 Issue 2 pp 215 248 http adsabs harvard edu abs 2011PASA 28 215N Johnston S et al Science with ASKAP The Australian square kilometre array pathfinder Experimental Astronomy 2008 Volume 22 p 151 http adsabs harvard edu abs 2008ExA 22 151J Umana G et al SCORPIO a deep survey of radio emission from the stellar life cycle MNRAS 2015 Volume 454 p 902 http adsabs harvard edu abs 2015MNRAS 454 902U Hopkins A et al The ASKAP EMU Source Finding Data Challenge PASA 2015 in press http adsabs harvard edu abs 2015arXiv150903931H Fan D et al Matching radio catalogues with realistic geometry application to SWIRE and ATLAS MNRAS 2015 451 1299 http adsabs harvard edu abs 2015MNRAS 451 1299F Banfield J et al Radio Galaxy Zoo host galaxies and radio morphologies derived from visual inspection MNRAS 2015 453 2326 http adsabs harvard edu abs 2015MNRAS 453 2326B Gaensler B et al Survey Science with ASKAP Polarization Sky Survey of the Universe s Magnetism POSSUM Bulletin of the American Astronomical Society 2010 Vol 42 p 515 http adsabs harvard edu abs 2010AAS 21547013G Norris R P et al The Evolutionary Map of the Universe pilot survey PASA 2021 Volume 38 p 46 https ui adsabs harvard edu abs 2021PASA 38 46NExternal links editEMU Outreach page EMU Project wiki EMU Newsletter Retrieved from https en wikipedia org w index php title Evolutionary Map of the Universe amp oldid 1176223284, wikipedia, wiki, book, books, library,
