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If gamma-ray bursts originate at cosmological distances then their angular distribution should exhibit a dipole in the direction of the solar motion relative to the cosmic microwave background. This is due to the combined effects of…

Astrophysics · Physics 2009-10-22 Eyal Maoz

The assumption of isotropy -- that the Universe looks the same in all directions on large scales -- is fundamental to the standard cosmological model. This model forms the building blocks of essentially all of our cosmological knowledge to…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-29 Jessica A. Cowell , Suhail Dhawan , Hayley J. Macpherson

We used the FourStar near-IR camera on Magellan-Baade to obtain high S/N H-Band imaging of 66 galaxies with radial velocities of 2000 < V < 5000 km/s. Our goal was to use the superior distance measurements of surface-brightness-fluctuations…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-11 Alan Dressler , Andrew Monson

Astronomical observations showed that there may exist a bulk flow with peculiar velocities in the universe, which contradicts with the (\Lambda)CDM model. The bulk flow reveals that the observational universe is anisotropic at large scales.…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-07 Zhe Chang , Ming-Hua Li , Sai Wang

We test anisotropic dark energy models with the 7-year WMAP temperature observations data. In the presence of imperfect sources, due to large-scale gradients or anisotropies in the dark energy field, the CMB sky will be distorted…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-08 Magnus J. Axelsson , Frode K. Hansen , Tomi Koivisto , David F. Mota

The cosmic dipole anomaly, currently detected at a significance exceeding 5$\sigma$ in several independent survey poses a significant challenge to the standard model of cosmology. The Ellis & Baldwin formula provides a theoretical link…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-29 Albert Bonnefous

We present a measurement of the velocity flow of the local universe relative to the CMB rest frame, based on the Jha, Riess & Kirshner (2007) sample of 133 low redshift type Ia supernovae. At a depth of 4500 km/s we find a dipole amplitude…

We estimate the level of confusion to Cosmic Microwave Background anisotropy measurements caused by extragalactic infrared sources. CMB anisotropy observations at high resolution and high frequencies are especially sensitive to this…

Astrophysics · Physics 2009-10-28 Eric Gawiser , George F. Smoot

The existence of a radio synchrotron background (RSB) excess is implied by a number of measurements, including excess emission seen by the ARCADE~2 and LWA experiments. Highly sensitive wideband radio arrays, of the kind used to measure the…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-16 Zheng Zhang , Philip Bull , Katrine A. Glasscock

The local void model has recently attracted considerable attention because it can explain the apparent accelerated expansion of the present universe without introducing dark energy. However, in order to justify this model as an alternative…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-27 Hideo Kodama , Keiki Saito , Akihiro Ishibashi

Our peculiar velocity with respect to the CMB rest frame is known to induce a large dipole in the CMB. However, the motion of an observer has also the effect of distorting the anisotropies at all scales, as shown by Challinor and Van…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-07 Luca Amendola , Riccardo Catena , Isabella Masina , Alessio Notari , Miguel Quartin , Claudia Quercellini

We present a simple, yet accurate approximation for calculating the cosmic microwave background anisotropy power spectrum in adiabatic models. It consists of solving for the evolution of a two-fluid model until the epoch of recombination…

Astrophysics · Physics 2009-10-22 Uros Seljak

Analyses of recent cosmic microwave background (CMB) observations have provided increasing indications for the existence of large scale anisotropy in the universe. Given the far reaching consequences of such an anisotropy for our…

Astrophysics · Physics 2009-09-29 A. Bernui , B. Mota , M. J. Reboucas , R. Tavakol

We generate the peculiar velocity field for the 2MASS Redshift Survey (2MRS) catalog using an orbit-reconstruction algorithm. The reconstructed velocities of individual objects in 2MRS are well-correlated with the peculiar velocities…

Astrophysics · Physics 2012-02-08 G. Lavaux , R. Brent Tully , R. Mohayaee , S. Colombi

Galactic foreground emission is a limiting factor for precise cosmic microwave background (CMB) anisotropy measurements. We perform an angular power spectrum analysis (APS) of all-sky total intensity maps at 408 MHz and 1420 MHz, which are…

Astrophysics · Physics 2009-11-13 L. La Porta , C. Burigana , W. Reich , P. Reich

The unprecedented sky coverage and photometric uniformity of the Two Micron All Sky Survey (2MASS) provides a rich resource for investigating the galaxies populating the local Universe. A full characterization of the large-scale clustering…

Astrophysics · Physics 2009-11-07 Ariyeh H. Maller , Daniel H. McIntosh , Neal Katz , Martin D. Weinberg

Breakdown of rotational invariance of the primordial power spectrum manifests in the statistical anisotropy of the observed Cosmic Microwave Background (CMB) radiation. Hemispherical power asymmetry in the CMB may be caused due to a dipolar…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-23 Md Ishaque Khan , Rajib Saha

In this paper, we study the anisotropy of cosmic acceleration the using Pantheon sample, which includes 1048 spectroscopically confirmed Type Ia supernovae (SNe Ia) covering the redshift range $0.01 < z < 2.3$. In hemisphere comparison…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-05 Z. Q. Sun , F. Y. Wang

A combined sample of 79 high and low redshift supernovae Ia (SNe) is used to set constraints on the degree of anisotropy in the Universe out to $z\simeq1$. First we derive the global most probable values of matter density $\Omega_M $, the…

Astrophysics · Physics 2015-06-24 Tsafrir S. Kolatt , Ofer Lahav

The source count dipole from wide-area radio continuum surveys allows us to test the cosmological standard model. Many radio sources have multiple components, which can cause an overdispersion of the source counts distribution. We account…