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The new fundamental plane dictating galaxy cluster evolution
- Yutaka Fujita, Keiichi Umetsu, Elena Rasia, Massimo Meneghetti, Megan Donahue, Elinor Medezinski, Nobuhiro Okabe, Marc Postman, Stefano Ettori
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- Journal:
- Proceedings of the International Astronomical Union / Volume 15 / Issue S341 / November 2019
- Published online by Cambridge University Press:
- 10 June 2020, pp. 271-272
- Print publication:
- November 2019
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In this study, we show that the characteristic radius rs, mass Ms, and the X-ray temperature, TX, of galaxy clusters form a thin plane in the space of (log rs, log Ms, log TX). This tight correlation indicates that the cluster structure including the temperature is affected by the formation time of individual clusters. Numerical simulations show that clusters move along the fundamental plane as they evolve. The plane and the cluster evolution within the plane can be explained by a similarity solution of structure formation. The angle of the plane shows that clusters have not achieved “virial equilibrium”. The details of this study are written in Fujita et al. (2018a,b).
ATLAS probe: Breakthrough science of galaxy evolution, cosmology, Milky Way, and the Solar System
- Yun Wang, Massimo Robberto, Mark Dickinson, Lynne A. Hillenbrand, Wesley Fraser, Peter Behroozi, Jarle Brinchmann, Chia-Hsun Chuang, Andrea Cimatti, Robert Content, Emanuele Daddi, Henry C. Ferguson, Christopher Hirata, Michael J. Hudson, J. Davy Kirkpatrick, Alvaro Orsi, Russell Ryan, Alice Shapley, Mario Ballardini, Robert Barkhouser, James Bartlett, Robert Benjamin, Ranga Chary, Charlie Conroy, Megan Donahue, Olivier Doré, Peter Eisenhardt, Karl Glazebrook, George Helou, Sangeeta Malhotra, Lauro Moscardini, Jeffrey A. Newman, Zoran Ninkov, Michael Ressler, James Rhoads, Jason Rhodes, Daniel Scolnic, Stephen Smee, Francesco Valentino, Risa H. Wechsler
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- Journal:
- Publications of the Astronomical Society of Australia / Volume 36 / 2019
- Published online by Cambridge University Press:
- 08 April 2019, e015
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Astrophysics Telescope for Large Area Spectroscopy Probe is a concept for a National Aeronautics and Space Administration probe-class space mission that will achieve ground-breaking science in the fields of galaxy evolution, cosmology, Milky Way, and the Solar System. It is the follow-up space mission to Wide Field Infrared Survey Telescope (WFIRST), boosting its scientific return by obtaining deep 1–4 μm slit spectroscopy for ∼70% of all galaxies imaged by the ∼2 000 deg2 WFIRST High Latitude Survey at z > 0.5. Astrophysics Telescope for Large Area Spectroscopy will measure accurate and precise redshifts for ∼200 M galaxies out to z < 7, and deliver spectra that enable a wide range of diagnostic studies of the physical properties of galaxies over most of cosmic history. Astrophysics Telescope for Large Area Spectroscopy Probe and WFIRST together will produce a 3D map of the Universe over 2 000 deg2, the definitive data sets for studying galaxy evolution, probing dark matter, dark energy and modifications of General Relativity, and quantifying the 3D structure and stellar content of the Milky Way. Astrophysics Telescope for Large Area Spectroscopy Probe science spans four broad categories: (1) Revolutionising galaxy evolution studies by tracing the relation between galaxies and dark matter from galaxy groups to cosmic voids and filaments, from the epoch of reionisation through the peak era of galaxy assembly; (2) Opening a new window into the dark Universe by weighing the dark matter filaments using 3D weak lensing with spectroscopic redshifts, and obtaining definitive measurements of dark energy and modification of General Relativity using galaxy clustering; (3) Probing the Milky Way’s dust-enshrouded regions, reaching the far side of our Galaxy; and (4) Exploring the formation history of the outer Solar System by characterising Kuiper Belt Objects. Astrophysics Telescope for Large Area Spectroscopy Probe is a 1.5 m telescope with a field of view of 0.4 deg2, and uses digital micro-mirror devices as slit selectors. It has a spectroscopic resolution of R = 1 000, and a wavelength range of 1–4 μm. The lack of slit spectroscopy from space over a wide field of view is the obvious gap in current and planned future space missions; Astrophysics Telescope for Large Area Spectroscopy fills this big gap with an unprecedented spectroscopic capability based on digital micro-mirror devices (with an estimated spectroscopic multiplex factor greater than 5 000). Astrophysics Telescope for Large Area Spectroscopy is designed to fit within the National Aeronautics and Space Administration probe-class space mission cost envelope; it has a single instrument, a telescope aperture that allows for a lighter launch vehicle, and mature technology (we have identified a path for digital micro-mirror devices to reach Technology Readiness Level 6 within 2 yr). Astrophysics Telescope for Large Area Spectroscopy Probe will lead to transformative science over the entire range of astrophysics: from galaxy evolution to the dark Universe, from Solar System objects to the dusty regions of the Milky Way.
Hot gas in clusters of galaxies and ΩM
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- By Megan E. Donahue, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 USA
- Edited by Mario Livio, Space Telescope Science Institute, Baltimore
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- Book:
- The Dark Universe
- Published online:
- 21 August 2009
- Print publication:
- 26 February 2004, pp 34-45
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Summary
X-ray clusters provide excellent constraints on cosmological parameters such as ΩM. I will describe measurements of cluster masses and of cluster evolution. The cluster baryon fraction and the evolution of the cluster temperature function strongly constrain the mean density of matter in the universe (ΩM). The constraints are consistent with ΩM = 0.2–0.5, with best fit values of ΩM = 0.3–0.4. The systematic uncertainties are of the same size as the statistical uncertainties, even with the small number of clusters in our current temperature surveys (ΔΩM ∼ 0.1.) Thus, reduction of the uncertainties in these methods requires not only an increased number of hot massive clusters in a given sample but much better quantification of the systematics, a goal which demands not only more clusters but clusters with a range of properties and redshifts. The current constraints are not particularly sensitive to the particular form or value of the acceleration parameter Λ and therefore these constraints provide an limit on cosmological parameters complementary to the limits imposed by the cosmic microwave background studies and by the Type Ia supernovae at cosmological distances.
Introduction
I seek to make the following three points in this review:
(a) Clusters of galaxies are excellent targets for cosmological studies.
(b) Existing studies have already placed very strong constraints on the mean density of matter in the universe.
(c) These constraints are nearly orthogonal to constraints from the cosmic microwave background and type Ia supernovae.
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7 - Clusters of galaxies and the fate of the Universe (Or how to be a cosmologist without really trying)
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- By Megan Donahue, Space Telescope Science Institute
- Edited by Alan Stern, Southwest Research Institute, Boulder, Colorado
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- Book:
- Our Universe
- Published online:
- 03 September 2009
- Print publication:
- 08 March 2001, pp 107-126
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Summary
Megan Donahue makes her living studying clusters of galaxies and intergalactic gas, and tending the on-line data archives of the Hubble Space Telescope at the Space Telescope Science Institute. She lives in Towson, Maryland, with her astronomer husband Mark Voit, and their two children, Michaela and Sebastian. Megan was born and raised in rural Nebraska, was an undergraduate in physics at MIT, and earned her PhD in astronomy at the University of Colorado Boulder. She went on to postdoctoral positions at Carnegie Observatories and the Space Telescope Science Institute, where she works now as a staff astronomer. Megan is a bright light among young extragalactic observers, and the coauthor of the astronomy textbook, The Cosmic Perspective by Jeffrey Bennett, Megan Donahue, Nicholas Schneider, and Mark Voit (Addison-Wesley, 1999). Here, she tells us the intertwined story of her own coming of age in science, and a trail of clues that is leading us toward a better understanding of galaxy clusters.
The concept of Fate makes me nervous. Yet, with a handful of observations made from our tiny corner of the Galaxy, we can determine the fate of the entire Universe. We have known since the late 1920s that the Universe is expanding. But what we are just beginning to discover is whether the Universe will expand forever or will eventually stop expanding and collapse in on itself.