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Since recent X-ray observations have revealed that most clusters of galaxies are surrounded by an X-ray emitting gaseous halo, it is reasonable to expect that the Local Group of galaxies has its own X-ray halo. We show that such a halo,…

Astrophysics · Physics 2009-10-28 Yasushi Suto , Kazuo Makishima , Yoshitaka Ishisaki , Yasushi Ogasaka

Since recent X-ray observations have revealed that most clusters of galaxies are surrounded by an X-ray emitting gaseous halo, it is reasonable to expect that the Local Group of galaxies has its own X-ray halo. We show that such a halo,…

Astrophysics · Physics 2007-05-23 Yasushi Suto

We investigate the effect of a putative X-ray emitting halo surrounding the Local Group of galaxies, and specifically the possible temperature anisotropies induced in the COBE-DMR four-year sky maps by an associated Sunyaev-Zel'dovich…

Astrophysics · Physics 2016-06-08 A. J. Banday , K. M. Gorski

An X-ray study was made to examine whether some part of the soft X-ray background is coming from hot gas in the Local Group. For this purpose, four consecutive pointings were made with ASCA toward a sky region between M 31 and M 33, which…

A simple model for a hot Local Group halo is constructed, using the standard beta-model for the halo density and by choosing model parameters based on all available observations of X-ray emission in other groups of galaxies and on optical…

Astrophysics · Physics 2009-11-06 Jesper Rasmussen , Kristian Pedersen

Several anomalies have been identified which may imply a breakdown of the statistical isotropy of the cosmic microwave background (CMB). In particular, an anomalous alignment of the quadrupole and octopole and a hemispherical power…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Hiranya V. Peiris , Tristan L. Smith

The hard X-ray (>2 keV) emission of the local and distant Universe as observed with the HEAO1-A2 experiment is reconsidered in the context of large scale cosmic structure. Using all-sky X-ray samples of AGN and galaxy clusters we remove the…

Astrophysics · Physics 2009-10-31 C. A. Scharf , K. Jahoda , M. Treyer , O. Lahav , E. Boldt , T. Piran

The negative evolution found in X--ray clusters of galaxies limits the amount of available hot gas for the inverse Compton scattering of the Cosmic Microwave Background (the Sunyaev--Zel'dovich effect). Using a parametrisation of the X-ray…

Astrophysics · Physics 2015-06-24 M. T. Ceballos , X. Barcons

Hot gas trapped in a dark matter halo will produce a decrement in the surface brightness of the microwave background, the Sunyaev-Zel'dovich (SZ) effect. While massive clusters produce the strongest central SZ decrements, we point out that…

Astrophysics · Physics 2009-11-07 James E. Taylor , Kavilan Moodley , J. M. Diego

The cosmic microwave background (CMB) contains an anomalous cold spot with a surrounding hot ring, known as the Cold Spot. Inoue & Silk (2006) proposed that this feature could be explained by postulating a supervoid: if such a large…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-14 Yuichi Higuchi , Kaiki Taro Inoue

It has been argued that the flux anomalies detected in gravitationally lensed QSOs are evidence for substructures in the foreground lensing haloes. In this paper we investigate this issue in greater detail focusing on the Cusp relation…

Astrophysics · Physics 2009-11-11 Andrea V. Maccio' , Marco Miranda

We confirm for the first time the existence of distinctive halo bias associated with the quadrupolar type of statistical anisotropy (SA) of the linear matter density field using cosmological $N$-body simulations. We find that the…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-19 Shogo Masaki , Maresuke Shiraishi , Takahiro Nishimichi , Teppei Okumura , Shuichiro Yokoyama

We show that the thermal Sunyaev-Zeldovich effect caused by hot electrons in the Local Supercluster (LSC) can explain the abnormal quadrupole and octopole of the cosmic microwave background (CMB) that were measured by WMAP and COBE. The…

Astrophysics · Physics 2007-05-23 L. Raul Abramo , L. Sodre

In this Letter we explore the effects of the scattering of photons incident on a dark matter halo through their interaction with either electrons or photons produced by dark matter annihilation. Particularly, we examine the effects of this…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-13 Geoff Beck , Sergio Colafrancesco

We study the implications of a pseudo-phase-space density power-law for the anisotropy profile of a Milky Way-like dark matter halo. Requiring that the anisotropy parameter does not take non-physical values within the virial radius places a…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-18 Daniel R. Hunter

Models in which a large fraction of the Galactic dark matter takes the form of cold gas clouds imply that there is thermal microwave emission from the Galactic dark halo. Such models can therefore be directly constrained by data on the…

Astrophysics · Physics 2007-05-23 Mark Walker , Michiko Ohishi , Masaki Mori

The existence of the cosmic ray Halo in our Galaxy has been discussed for more than half a century. If it is real it could help to explain some puzzling features of the cosmic ray flux: its small radial gradient, nearly perfect isotropy and…

Astrophysics of Galaxies · Physics 2015-06-19 Anatoly Erlykin , Arnold Wolfendale

We measure the anisotropy of dark matter flows on small scales in the near environment of haloes using a large set of simulations. We rely on two different approaches to quantify the anisotropy of the cosmic infall: we measure the flows at…

Astrophysics · Physics 2009-11-10 Dominique Aubert , Christophe Pichon , Stephane Colombi

We study the effect of large-scale tidal fields on internal halo properties using a set of N-body simulations. We measure significant cross-correlations between large-scale tidal fields and several non-scalar halo properties: shapes,…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-16 Andrej Obuljen , Neal Dalal , Will J. Percival

X-ray emission and the thermal Sunyaev-Zel'dovich distortion to the Cosmic Microwave Background are two important handles on the gas content of the Universe. The cross-correlation between these effects eliminates noise bias and reduces…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-18 Victoria Lakey , Kevin Huffenberger
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