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We report limits on the Galactic foreground emission contribution to the Background Emission Anisotropy Scanning Telescope (BEAST) Ka- and Q-band CMB anisotropy maps. We estimate the contribution from the cross-correlations between these…

We describe different methods for estimating the bispectrum of Cosmic Microwave Background data. In particular we construct a minimum variance estimator for the flat-sky limit and compare results with previously-studied frequentist methods.…

We utilize new VLA Galactic plane catalogs at 5 and 1.4 GHz covering the first Galactic quadrant (350<l<42, |b|<0.4) in conjunction with the MSX6C Galactic plane catalog to construct a large sample of ultra-compact HII regions. A radio…

天体物理学 · 物理学 2009-11-10 Uriel Giveon , Robert H. Becker , David J. Helfand , Richard L. White

We extend the description of the isotropic and anisotropic random component of the small-scale magnetic field within the existing magnetic field model of the Milky Way from Jansson&Farrar, by including random realizations of the small-scale…

星系天体物理 · 物理学 2016-06-02 Marcus C. Beck , Alexander M. Beck , Rainer Beck , Klaus Dolag , Andrew W. Strong , Peter Nielaba

Gigahertz-Peaked spectrum (GPS) sources are compact active galactic nuclei, presumably young precursors of bright radio sources. The study of GPS radio properties provides information about the features of synchrotron radiation in…

星系天体物理 · 物理学 2020-01-08 Yu. Sotnikova , T. Mufakharov , E. Majorova , M. Mingaliev , R. Udovitskiy , N. Bursov , T. Semenova

Several anomalies appear to be present in the large-angle cosmic microwave background (CMB) anisotropy maps of WMAP, including the alignment of large-scale multipoles. Models in which isotropy is spontaneously broken (e.g., by a scalar…

宇宙学与河外天体物理 · 物理学 2015-03-13 Haoxuan Zheng , Emory F. Bunn

We report the direct detection of gamma-ray emission from the Galactic center in the 150-600 keV band using the electron-tracking Compton camera (ETCC), which has a wide field of view of 3.1 sr. This represents the first application of this…

Noncoherent communication systems have regained interest due to the growing demand for high-mobility and low-latency applications. Most existing studies using large antenna arrays rely on the far-field approximation, which assumes locally…

信号处理 · 电气工程与系统科学 2025-05-26 Aniol Martí , Luca Sanguinetti , Meritxell Lamarca , Jaume Riba

We report results from the observations of the well studied TeV blazar Mrk 421 with the Swift and the Suzaku satellites in December 2008. During the observation, Mrk 421 was found in a relatively low activity state, with the corresponding…

宇宙学与河外天体物理 · 物理学 2015-05-19 M. Ushio , L. Stawarz , T. Takahashi , D. Paneque , G. Madejski , M. Hayashida , J. Kataoka , Y. T. Tanaka , T. Tanaka , M. Ostrowski

Using data from the Wide-field Infrared Survey Explorer we studied the mid infrared 3.4 $\mu$m (W1-band) and 4.6 $\mu$m (W2-band) flux variability of $\gamma$-ray emitting blazars. Our sample consists of 460 flat spectrum radio quasars…

星系天体物理 · 物理学 2020-04-15 Ayesha Anjum , C. S. Stalin , Suvendu Rakshit , S. B. Gudennavar , Alok Durgapal

The radio continuum spectra of 14 star-forming galaxies are investigated by fitting nonthermal (synchrotron) and thermal (free-free) radiation laws. The underlying radio continuum measurements cover a frequency range of ~325 MHz to 24.5 GHz…

星系天体物理 · 物理学 2018-03-28 Uli Klein , Ute Lisenfeld , Simon Verley

The recent data release of ESA's Planck mission together with earlier WMAP releases provide the first opportunity to compare high resolution full sky Cosmic Microwave Background temperature anisotropy maps. To quantify the coherence of…

宇宙学与河外天体物理 · 物理学 2015-06-16 András Kovács , Julien Carron , István Szapudi

Context: The relation between Galactic cosmic-ray electrons, magnetic fields and synchrotron radiation. Aims: We exploit synchrotron radiation to constrain the low-energy interstellar electron spectrum, using various radio surveys and…

高能天体物理现象 · 物理学 2011-10-03 A. W. Strong , E. Orlando , T. R. Jaffe

We detect anisotropy in the cosmic microwave background (CMB) at degree angular scales and confirm a previous detection reported by Wollack et al. (1993). The root-mean-squared amplitude of the fluctuations is $44^{+13}_{-7} \mu$K. This may…

天体物理学 · 物理学 2008-11-26 C. B. Netterfield , N. Jarosik , L. Page , D. Wilkinson , E. Wollack

First results of a Cosmic Microwave Background (CMB) anisotropy experiment conducted at the Observatorio del Teide (Tenerife, Spain) are presented. The instrument is a four channel (3.1, 2.1, 1.3 and 1.1 mm) $^3$He bolometer system coupled…

We present 2-4 GHz observations of polarized radio galaxies towards eight fast radio bursts (FRBs), producing grids of Faraday rotation measure (RM) sources with sky densities of 9-28 polarized sources per square degree. Using a Bayesian…

We use the local curvature to investigate the possible existence of non-Gaussianity/asymmetry in the WMAP data. Considering the full sky we find results which are consistent with the Gaussian assumption. However, strong non-Gaussian…

天体物理学 · 物理学 2010-04-06 Frode K. Hansen , Paolo Cabella , Domenico Marinucci , Nicola Vittorio

Aims. We use 5 years of Fermi-LAT data towards the Galactic-centre giant molecular cloud complex, Sagittarius B, to test questions of how well-mixed the Galactic component of cosmic rays are and what the level of the cosmic-ray sea in…

高能天体物理现象 · 物理学 2015-08-12 Rui-zhi Yang , David I. Jones , Felix Aharonian

We re-examine the observational evidence for large-scale (4 Mpc) galactic conformity in the local Universe, as presented in Kauffmann et al. (2013). We show that a number of methodological features of their analysis act to produce a…

星系天体物理 · 物理学 2017-09-06 Larry P. T. Sin , Simon J. Lilly , Bruno M. B. Henriques

We apply the Gabor transform methodology proposed in (Hansen et al. 2002, 2003) to the WMAP data in order to test the statistical properties of the CMB fluctuation field and specifically to evaluate the fundamental assumption of…

天体物理学 · 物理学 2009-05-29 F. K. Hansen , A. J. Banday , K. M. Gorski