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We present sensitive upper limits on the 90 GHz flux of known radio and infrared sources in regions associated with possible cosmic microwave background fluctuations at 0.5--1 degree scales. Specifically we look at the MAX GUM region and…

Astrophysics · Physics 2007-05-23 Lawrence M. Chernin , Douglas Scott

We use absolutely calibrated data from the ARCADE 2 flight in July 2006 to model Galactic emission at frequencies 3, 8, and 10 GHz. The spatial structure in the data is consistent with a superposition of free-free and synchrotron emission.…

Astrophysics of Galaxies · Physics 2011-05-23 A. Kogut , D. J. Fixsen , S. M. Levin , M. Limon , P. M. Lubin , P. Mirel , M. Seiffert , J. Singal , T. Villela , E. Wollack , C. A. Wuensche

We estimate the spectral index, beta, of polarized synchrotron emission as observed in the 9 yr WMAP sky maps using two methods, linear regression ("T-T plot") and maximum likelihood. We partition the sky into 24 disjoint sky regions, and…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-04 U. Fuskeland , I. K. Wehus , H. K. Eriksen , S. K. Næss

We report on the first flight of the balloon-borne QMAP experiment. The experiment is designed to make a map of the cosmic microwave background anisotropy on angular scales from 0.7 to several degrees. Using the map we determine the angular…

Low-frequency radio surveys allow in-depth studies and new analyses of classes of sources previously known and characterised only in other bands. In recent years, low radio frequency observations of blazars have been available thanks to new…

Astrophysics of Galaxies · Physics 2020-01-08 Daniele d'Antonio , Marcello Giroletti , Gabriele Giovannini , Alessandro Maini

We study the apparent lack of power on large angular scales in the WMAP data. We confirm that although there is no apparent lack of power at large angular scales for the full-sky maps, the lowest multipoles of the WMAP data happen to have…

Astrophysics · Physics 2007-05-23 Amir Hajian

We address the amount of information in the non-Gaussian regime of weak lensing surveys by modelling all relevant covariances of the power spectra and bispectra, using 1000 ray-tracing simulation realizations for a Lambda-CDM model and an…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-09 Issha Kayo , Masahiro Takada , Bhuvnesh Jain

It has been argued recently that the galaxy peculiar velocity field provides evidence of excessive power on scales of $50\hmpc$, which seems to be inconsistent with the standard $\Lambda$CDM cosmological model. We discuss several…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Yin-Zhe Ma , Douglas Scott

We present results of variability study of a sample of 20 powerful blazars using Fermi/LAT (0.1--300 GeV) observations. We studied decade-long observations applying various analysis tools such as flux distribution, symmetry analysis, and…

High Energy Astrophysical Phenomena · Physics 2021-07-27 Gopal Bhatta , Niraj Dhital

We present results from the QMAP balloon experiment, which maps the Cosmic Microwave Background (CMB) and probes its angular power spectrum on degree scales. In two separate flights, data were taken in six channels at two frequency bands…

We present the first results from a Bayesian analysis of the WMAP first year data using a Gibbs sampling technique. Using two independent, parallel supercomputer codes we analyze the WMAP Q, V and W bands. The analysis results in a full…

We repeat and extend the analysis of Eriksen et al 2004 and Hansen et al 2004 testing the isotropy of the Cosmic Microwave Background (CMB) fluctuations. We find that the hemispherical power asymmetry previously reported for the largest…

Astrophysics · Physics 2014-11-18 F. K. Hansen , A. J. Banday , K. M. Gorski , H. K. Eriksen , P. B. Lilje

The broadband spectral energy distribution of a galaxy encodes valuable information on its stellar mass, star formation rate (SFR), dust content, and possible fractional energy contribution from nonstellar sources. We present a…

Astrophysics of Galaxies · Physics 2023-07-26 Yang A. Li , Luis C. Ho , Jinyi Shangguan , Ming-Yang Zhuang , Ruancun Li

We investigate the occurrence of multiple weak deflections in deep data sets which are used to detect galaxy-galaxy lensing. Using the galaxies in the HDF (North) for which both redshifts and rest-frame blue luminosities are known, we show…

Astrophysics · Physics 2007-05-23 C. O. Wright , T. G. Brainerd

We have measured the Faraday rotation of 62 extra-galactic background sources in 58 fields using the CSIRO Australia Telescope Compact Array (ATCA) with a frequency range of 1.1 - 3.1 GHz with 2048 channels. Our sources cover a region $\sim…

Astrophysics of Galaxies · Physics 2021-02-03 J. D. Livingston , N. M. McClure-Griffiths , B. M. Gaensler , A. Seta , M. J. Alger

The amplitudes of the quadrupole and octopole measured from the Wilkinson Microwave Anisotropy Probe (WMAP) appear to be lower than expected according to the concordance Lambda CDM cosmology. However, the pseudo-Cl estimator used by the…

Astrophysics · Physics 2009-07-09 G. Efstathiou

We introduce a method for removing CMB and anomalous microwave emission (AME, or spinning dust) intensity signals at high to intermediate Galactic latitudes in temperature sky maps at frequencies roughly between 5 and 40 GHz. The method…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-23 J. L. Weiland , Charles L. Bennett , Graeme E. Addison , Mark Halpern , Gary Hinshaw

Studying gamma-ray emission by Galactic objects is key to understanding the origins and acceleration mechanisms of Galactic cosmic ray electrons and hadrons. The HAWC observatory provides an unprecedented view of the gamma-ray sky at TeV…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Henrike Fleischhack , Petra Huentemeyer

Despite significant progress over more than 100 years, no accelerator has been unambiguously identified as the source of the locally measured flux of cosmic rays. High-energy electrons and positrons are of particular importance in the…

High Energy Astrophysical Phenomena · Physics 2018-11-30 Philipp Mertsch

In order to construct accurate point sources simulations at the frequencies relevant to 21 cm experiments, the angular correlation of radio sources must be taken into account. Using the 74 MHz VLSS survey, we measured the angular 2-point…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Angelica de Oliveira-Costa , John Capodilupo