Amy J. Barger (born January 18, 1971) is an American astronomer and Henrietta Leavitt Professor of Astronomy at the University of Wisconsin–Madison. She is considered a pioneer in combining data from multiple telescopes to monitor multiple wavelengths and in discovering distant galaxies and supermassive black holes, which are outside of the visible spectrum. Barger is an active member of the International Astronomical Union.[1][2][3]
Education and career
Barger earned a Bachelor of Arts in astronomy-physics in 1993 from the University of Wisconsin-Madison. She was a Marshall scholar at King's College, University of Cambridge and received a doctor of philosophy in astronomy from the university in 1997.[4] Barger holds positions as a Henrietta Leavitt Professor of Astronomy at the University of Wisconsin-Madison and as an affiliate graduate faculty member in the University of Hawaii Department of Physics and Astronomy.[5]
Notable research
Barger's research discoveries concern distant Universe activity and objects, including dusty galaxies, quasars and supermassive black holes.[5] Her research has overturned current and widely accepted models of how galaxies and supermassive black holes evolve.[1]
University of Hawaii
From 1996 to 2000, Barger received a postdoctoral fellowship from the University of Hawaii Institute for Astronomy.[5] During this time, she was a part of the MORPHS collaboration, a research group that studied the formation and morphologies of distant galaxies.[6] Based on the data they retrieved from Hubble Space Telescope Wide Field and Planetary Camera 2 images, photometry and spectroscopy, the group was able to analyze and catalogue approximately 2,000 distant galaxies in 10 clusters and conclude that the spectral and morphological transformation of the galaxies were affected by two different timescales and/or physical processes.[7][8]
Barger also used the Submillimetre Common-User Bolometer Array (SCUBA), a far-infrared camera, to discover new quasars, and as a 1999 Hubble Fellow and Chandra Fellow at large,[5][9] she was granted access to NASA's Chandra X-Ray Observatory (CXO).
In January 2000, the results of Barger and her colleagues' search for the origins of the cosmic X-ray background were presented at the 195th national meeting of the American Astronomical Society in Atlanta, Georgia. With the data they gathered from their research in the CXO, the team furthered previous research in finding that about one-third of the origins of the X-ray background are active galactic nuclei (AGNs) that emit light not on the visible spectrum. The AGNs contain a massive black hole that produces X-rays as gas is pulled toward them at virtually the speed of light. The team also found that ultra-faint galaxies are a source of another third of the X-ray background. The ultra-faint galaxies emit little to no visible light due to dust formation around them or due to the absorption of visible light by cool gas. The team concluded that more optical observations with more powerful telescopes, such as the Next Generation Space Telescope and Constellation-X, were required to gain more insight into the two types of far-distant objects they observed.[10][11]
As a follow-up to the research presented in January, Barger lead a team in surveying black holes. The team used a Keck 10-meter telescope, James Clerk Maxwell Telescope and the Very Large Array of the National Radio Astronomy Observatory to study the time intervals for black hole growth and found that the activity of an abundance of black holes in nearby galaxies was greater and more recent than once thought. The team concluded that, contrary to widespread belief, not all black holes formed when galaxies did. Rather, there are black holes currently growing slowly, taking more than one billion years to form. In December 2000, Barger led the presentation of the findings at a press conference at the 20th Texas Symposium on Relativistic Astrophysics, in Austin, Texas.[3][12]
University of Wisconsin-Madison
In 2000, Barger became an assistant professor of astronomy at the University of Wisconsin-Madison while completing her University of Hawaii fellowship and eventually joining the faculty as a visiting adjunct astronomer.[13]
In 2001, she received the American Association of University Women Annie Jump Cannon Award in Astronomy for her investigation of the X-ray background, which would lead to future spectroscopic research. During this time, Barger was on faculty leave from the University of Wisconsin-Madison to conduct research at the University of Hawaii and had earned a grant from the National Science Foundation to fund her work.[14]
In 2002, she won the Newton Lacy Pierce Prize in Astronomy for outstanding achievement in observational astronomical research over the past five years.[5][15] In October 2003, Barger was awarded a $625,000 Packard Foundation Fellowship for Science and Engineering toward her research.[13]
In 2005, the results of a study led by Barger concerning how black holes and galaxies grow was published in The Astronomical Journal. The team captured and observed long-exposure X-ray images of black holes normally obscured by gas and dust to determine that they are between one and 12 billion light-years away from Earth. With Chandra Deep Field North and South, the Hubble Deep Field and images of the Lockman Hole, the researchers were able to accurately count the number of black holes that exist in between those that are the closest and farthest away from Earth. The team discovered that the earliest black holes, which are a part of the early Universe and have at least 100 million times the mass of the Sun, quickly reach a size limit and stop accumulating matter. The black holes with a mass between 10 million and 100 million times that of the Sun continue to accumulate matter and grow slowly in comparison.[16][17][18] The researchers found that one or more systems connect a galaxy's formation of stars to its loss of cosmic materials through its black hole because the processes occur simultaneously. Barger and her team refer to the apparent shift in star formation from massive galaxies to relatively lightweight ones as 'cosmic downsizing' and as this phenomenon continues, dwarf galaxies will be the main source of star formation before the universe darkens as older galaxies fade away.[19]
Barger and her colleagues' research on the early Universe[1] has informed cosmic stratigraphy, which is the process of obtaining redshifts of galaxies through deep-field images to chronologize galaxy and star formation since the Big Bang. The more redshifted galaxies are—or the closer to red the wavelength of the stretched light from galaxies are—the older, brighter, less numerous and farther away they are from Earth.[20][21]
In 2013, Barger, former advisee Ryan Keenan and astronomer Lennox Cowie published the results of a study on the density of galactic matter in The Astrophysical Journal. The team used redshift surveys and spectroscopy to observe and estimate the distribution of luminous and dark matter in a sample of galaxies and found that Earth's galaxy, the Milky Way, is inside of a large void named the KBC Void for the research team. As of 2017, the KBC Void is the largest-known void with a diameter of approximately 2 billion light-years.[22][23][24] In that same year, Barger's former student Benjamin Hoscheit presented the results of their follow-up study, in which Hoscheit used the linear kinematic Sunyaev-Zel'dovich (kSZ) effect to measure galaxy clusters' motions and confirm the existence of the spherical-shaped KBC Void, which is surrounded by a shell of galaxies, stars and other cosmic materials.[25][26]
Honors and awards
1992 Barry M. Goldwater Scholarship[27]
1993 Marshall Scholarship[28]
1999 NASA Hubble Fellowship[29]
1999 Chandra Fellow[30]
2001 Annie J. Cannon Award in Astronomy[31]
2002 Newton Lacy Pierce Prize of the American Astronomical Society[32]
2002 Alfred P. Sloan Foundation Fellow[33]
2003 Kavli Frontiers of Science Fellow[34]
2003 David and Lucille Packard Fellow[35]
2007 American Physical Society Fellow[36]
2007 Maria Goeppert-Mayer Award of the American Physical Society[37]
2015 John Simon Guggenheim Memorial Foundation Fellow[38]
2011 Vilas Associates Award at University of Wisconsin-Madison[39]
2017 American Association for the Advancement of Science Fellow[40]
2017 Kellett Mid-Career Award at University of Wisconsin-Madison[41]
2021 American Astronomical Society Fellow[42]
Notes
Kassulke, Natasha (May 25, 2021). "Faculty receive WARF Named Professorships, Kellett Fellowships, and Romnes Awards". University of Wisconsin-Madison. Retrieved July 26, 2021.
"International Astronomical Union | IAU". www.iau.org. Retrieved January 30, 2020.
Minkel, J.R. (October 2005). "The 4th Annual PopSci Brilliant 10". Pop Science. Bonnier Corporation. Retrieved July 26, 2021.
"Prize Recipient". APS Physics. Retrieved July 27, 2021.
"Frontiers of Astronomy Community Lecture". Institute for Astronomy, University of Hawaii. Retrieved July 26, 2021.
"MORPHS's Home Page". UK Mirror. Retrieved July 26, 2021.
Tanvir, Nial R.; Aragón-Salamanca, Alfonso; WAll, Jasper V. (1997). Hubble Space Telescope And The High Redshift Universe, The - Proceedings Of The 37th Herstmonceux Conference. World Scientific. pp. 185–186. ISBN 9789814530408. Retrieved July 27, 2021.
Poggianti, Bianca M.; Smail, Ian; Dressler, Alan; Couch, Warrick J.; Barger, Amy J.; Butcher, Harvey; Ellis, Richard S.; Oemler, Jr., Augustus (June 20, 1999). "The Star Formation Histories of Galaxies in Distant Clusters". The Astrophysical Journal. 518 (2): 576–593. arXiv:astro-ph/9901264. Bibcode:1999ApJ...518..576P. doi:10.1086/307322. S2CID 18257120.
"Chandra Fellows Named" (Press release). Cambridge, MA, USA: Center for Astrophysics | Harvard & Smithsonian. February 18, 1999. Retrieved July 27, 2021.
"Chandra Resolves Cosmic X-ray Glow and Finds Mysterious New Sources" (Press release). Cambridge, MA, USA: Center for Astrophysics | Harvard & Smithsonian. January 13, 2000. Retrieved July 27, 2021.
Altonn, Helen (December 12, 2000). "Many black holes formed later". Honolulu Star-Bulletin Hawaii News. Retrieved July 27, 2021.
"BLACK HOLES YOUNGER, MEANER, AND MORE PLENTIFUL THAN PREVIOUSLY THOUGHT" (Press release). Austin, Texas, USA: Institute for Astronomy at the University of Hawaii. December 12, 2000. Retrieved July 27, 2021.
"Barger Named Packard Fellow". Na Kilo Hoku. No. 10. Winter 2004. Retrieved July 27, 2021.
"AAUW Confers Cannon Prize on Barger" (PDF). American Astronomical Society Newsletter. Washington, D.C. June 2001. Retrieved July 27, 2021.
"Prestigious Astronomy Awards". Na Kilo Hoku. No. 3. Winter 2002. Retrieved July 29, 2021.
"NASA Observatory Confirms Black Hole Limits" (Press release). Cambridge, MA, USA: Center for Astrophysics | Harvard & Smithsonian. February 15, 2005. Retrieved July 26, 2021.
Altonn, Helen (February 17, 2005). "UH scientists find size limit to black holes". Star Bulletin. Retrieved July 26, 2021.
Barger, A. J.; Cowie, L. L.; Mushotzky, R. F.; Yang, Y.; Wang, W.-H.; Steffen, A. T.; Capak, P. (February 2005). "The Cosmic Evolution of Hard X-Ray-selected Active Galactic Nuclei". The Astronomical Journal. 129 (2): 578–609. arXiv:astro-ph/0410527. Bibcode:2005AJ....129..578B. doi:10.1086/426915. S2CID 17183341. Retrieved July 29, 2021.
Barger, Amy J. (April 1, 2017). "The Midlife Crisis of the Cosmos". Scientific American. Retrieved July 27, 2021.
Mundt, Phil (2007). A scientific search for religious truth. Austin, Tex.: Bridgeway Books. p. 316. ISBN 978-1933538617. Retrieved July 27, 2021.
Barger, Amy J. (April 2007). "The Midlife Crisis of the Cosmos". Scientific American. 17 (1): 58–65. doi:10.1038/scientificamerican0407-58sp. Retrieved July 27, 2021.
Moffat, John W. (2014). Cracking the particle code of the universe : the hunt for the Higgs boson. Oxford: Oxford University Press. p. 132. ISBN 9780199915538. Retrieved July 27, 2021.
Keenan, R. C.; Barger, A. J.; Cowie, L. L. (September 2013). "EVIDENCE FOR A $\sim$300 MEGAPARSEC SCALE UNDER-DENSITY IN THE LOCAL GALAXY DISTRIBUTION". The Astrophysical Journal. 775 (1): 62. arXiv:1304.2884. doi:10.1088/0004-637X/775/1/62. S2CID 118433293. Retrieved July 27, 2021.
Devitt, Terry (June 6, 2017). "Celestial boondocks: Study supports the idea that we live in a void". University of Wisconsin-Madison. Retrieved July 27, 2021.
Howell, Elizabeth (June 14, 2021). "We Live in a Cosmic Void, Another Study Confirms". Space. Retrieved July 27, 2021.
Hoscheit, Benjamin L.; Barger, Amy J. (February 9, 2018). "The KBC Void: Consistency with Supernovae Type Ia and the Kinematic SZ Effect in a ΛLTB Model". The Astrophysical Journal. 854 (1): 46. arXiv:1801.01890. Bibcode:2018ApJ...854...46H. doi:10.3847/1538-4357/aaa59b. S2CID 119220508. Retrieved August 10, 2021.
"Goldwater Scholars – Undergraduate Academic Awards – UW–Madison". awards.advising.wisc.edu. Retrieved January 30, 2020.
"1993 Marshall Scholarshiop" (PDF). Marshall Scholars Annual Report 2018. 2018. Archived (PDF) from the original on January 30, 2020. Retrieved January 29, 2020.
"2017 and Prior Fellows". STScI.edu. Retrieved January 30, 2020.
"Einstein, Chandra, and Fermi Fellows". cxc.harvard.edu. Retrieved January 30, 2020.
"Annie J. Cannon Award in Astronomy". American Astronomical Society. Archived from the original on September 9, 2015. Retrieved September 13, 2013.
"Newton Lacy Pierce Prize in Astronomy | American Astronomical Society". aas.org. Retrieved January 30, 2020.
"Past Fellows". sloan.org. Archived from the original on December 27, 2020. Retrieved January 30, 2020.
Mayeshiba, Tam T.; Morgan, Dane D. (November 2016). "Factors controlling oxygen migration barriers in perovskites". Solid State Ionics. 296: 71–77. arXiv:1609.03456. Bibcode:2016arXiv160903456M. doi:10.1016/j.ssi.2016.09.007. ISSN 0167-2738. S2CID 99986192.
"Barger, Amy J." The David and Lucile Packard Foundation. Retrieved January 30, 2020.
"APS Fellow Archive". www.aps.org. Retrieved January 30, 2020.
"2007 Maria Goeppert Mayer Award Recipient: Amy Barger". American Physical Society. Retrieved September 13, 2013.
"John Simon Guggenheim Foundation | Amy J. Barger". Retrieved January 30, 2020.
"Past Winners Vilas Associates | Research | UW–Madison". Retrieved January 30, 2020.
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"Past Winners Kellett Mid-Career | Research | UW–Madison". Retrieved January 30, 2020.
"AAS Names 31 New Fellows for 2021" (Press release). American Astronomical Society. February 2, 2021. Retrieved July 29, 2021.
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