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Post Info TOPIC: Sunyaev-Zel'dovich Effect
Blobrana


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Thermal Sunyaev-Zel'dovich Effect
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Title: The Atacama Cosmology Telescope: A Measurement of the Thermal Sunyaev-Zel'dovich Effect Using the Skewness of the CMB Temperature Distribution
Authors: Michael J. Wilson, Blake D. Sherwin, J. Colin Hill, Graeme Addison, Nick Battaglia, J. Richard Bond, Sudeep Das, Mark J. Devlin, Joanna Dunkley, Rolando Dunner, Joseph W. Fowler, Megan B. Gralla, Amir Hajian, Mark Halpern, Matt Hilton, Adam D. Hincks, Renee Hlozek, Kevin Huffenberger, John P. Hughes, Arthur Kosowsky, Thibaut Louis, Tobias A. Marriage, Danica Marsden, Felipe Menanteau, Kavilan Moodley, Michael D. Niemack, Michael R. Nolta, Lyman A. Page, Bruce Partridge, Erik D. Reese, Neelima Sehgal, Jon Sievers, David N. Spergel, Suzanne T. Staggs, Daniel S. Swetz, Eric R. Switzer, Hy Trac, Ed Wollack

We present a detection of the unnormalised skewness induced by the thermal Sunyaev-Zel'dovich (tSZ) effect in filtered Atacama Cosmology Telescope (ACT) 148 GHz cosmic microwave background temperature maps. Contamination due to infrared and radio sources is minimised by template subtraction of resolved sources and by constructing a mask using outlying values in the 218 GHz (tSZ-null) ACT maps. We measure = -31 ± 6 µ Kł (measurement error only) or ± 14 µ Kł (including cosmic variance error) in the filtered ACT data, a 5-sigma detection. We show that the skewness is a sensitive probe of sigma_8, and use analytic calculations and tSZ simulations to obtain cosmological constraints from this measurement. From this signal alone we infer a value of sigma_8= 0.78 +0.03 -0.04 (68 % C.L.) +0.05 -0.16 (95 % C.L.). Our results demonstrate that measurements of non-Gaussianity can be a useful method for characterising the tSZ effect and extracting the underlying cosmological information.

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Blobrana


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kinematic Sunyaev-Zel'dovich effect
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In 1972, a young astronomer predicted that moving clusters of galaxies would leave a subtle imprint on the cosmic microwave background radiation - but he had no way to check his prediction. Forty years later, another young astronomer has proved him right - by combining data from two huge international astronomy collaborations.
Tatar astrophysicist Rashid Sunyaev, working in Moscow with his advisor Yakov Zel'dovich, predicted in 1972 what would become known as the "kinematic Sunyaev-Zel'dovich (kSZ) effect." The tiny effect had eluded scientists for 40 years - until Nick Hand, as an undergraduate at Princeton University - worked with his advisor David Spergel to find it in combined data from the Atacama Cosmology Telescope (ACT) and the Sloan Digital Sky Survey (SDSS-III).
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Blobrana


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Posts: 131433
Date:
Sunyaev-Zel'dovich effect
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Rutgers, Chilean Astrophysicists Discover New Galaxy Clusters Revealed by Cosmic "Shadows"

An international team of scientists led by Rutgers University astrophysicists have discovered 10 new massive galaxy clusters from a large, uniform survey of the southern sky. The survey was conducted using a breakthrough technique that detects "shadows" of galaxy clusters on the cosmic microwave background radiation, a relic of the "big bang" that gave birth to the universe.
In a paper published in the Nov. 10 issue of Astrophysical Journal, the Rutgers scientists and collaborators at the Pontifical Catholic University of Chile (PUC) describe their visual telescope observations of these galaxy clusters, which were essential to verify the cosmic shadow sightings. Both observations will help scientists better understand how the universe was born and continues to evolve.
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Novel observing mode on XMM-Newton opens new perspectives on galaxy clusters

Surveying the sky, XMM-Newton has discovered two massive galaxy clusters, SPT-CL J2332-5358 and SPT-CL J2342-5411, confirming a previous detection obtained through observations of the Sunyaev-Zel'dovich effect, the 'shadow' they cast on the Cosmic Microwave Background. The discovery, made possible thanks to a novel mosaic observing mode recently introduced on ESA's X-ray observatory, opens a new window to study the Universe's largest bound structures in a multi-wavelength approach.
Galaxy clusters are the largest gravitationally bound objects in the Universe. As such, they are extremely important probes of cosmic properties on very large scales, since they form in the densest knots of the large-scale structure, the cosmic web. Originally discovered as an excess density (or cluster) of galaxies located at the same redshift, hence the name, there is much more to these enormous structures than mere galaxies: in fact, only about one tenth of the entire mass of a galaxy cluster arises from galaxies (up to a thousand in the most massive cases), another tenth consists of hot gas, and the remainder can be attributed to dark matter.
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