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Spectropolarimetry is a powerful technique that has provided critical support for the geometric unification model of local active galactic nuclei. In this paper, we present optical (rest-frame UV) Keck spectropolarimetry of five luminous…

Bright clusters of galaxies can be seen out to cosmological distances, and thus they can be used to derive cosmological parameters. Although the continuum X-ray emission from the intra-cluster gas is optically thin, the optical depth of…

Astrophysics · Physics 2009-11-11 S. M. Molnar , M. Birkinshaw , R. F. Mushotzky

The cosmic ray spectrum has been shown to extend well beyond 10^{20}eV. With nearly 20 events observed in the last 40 years, it is now established that particles are accelerated or produced in the universe with energies near 10^{21}eV. In…

Astrophysics · Physics 2014-10-13 X. Bertou , P. Billoir , O. Deligny , C. Lachaud , A. Letessier-Selvon

Measuring the angles of muons and electrons in air showers is proposed as a method for studying the primary cosmic-ray mass composition near the knee of the cosmic-ray energy spectrum at a few $10^{15}$ eV. Conventional tracking detectors…

Astrophysics · Physics 2009-10-28 Konrad Bernlöhr

Pulsar wind driven synchrotron nebulae are offering a unique view on the connection of the pulsar wind and the surrounding medium. The Crab nebula is particularly well suited for detailed studies of the different emission regions. As…

Astrophysics · Physics 2007-05-23 D. Horns , F. A. Aharonian

We present submillimeter polarimetry at 850 micron toward the filamentary star-forming region associated with the reflection nebulosity NGC 2068 in Orion B. These data were obtained using the James Clerk Maxwell Telescope's SCUBA…

Astrophysics · Physics 2009-11-07 B. C. Matthews , C. D. Wilson

We compute the angular power spectrum C_l from the BATSE 3B catalog of 1122 gamma-ray bursts, and find no evidence for clustering on any scale. These constraints bridge the entire range from small scales (which probe source clustering and…

Astrophysics · Physics 2009-10-07 Max Tegmark , Dieter Hartmann , Michael Briggs , Charles Meegan

The distribution of arrival directions of cosmic rays is remarkably isotropic, which is a consequence of their repeated scattering in magnetic fields. Yet, high-statistics observatories like IceCube and HAWC have revealed the presence of…

High Energy Astrophysical Phenomena · Physics 2019-12-04 Philipp Mertsch , Markus Ahlers

The nuclear region of Type 1 AGNs has only been partially resolved so far in the near-infrared (IR) where we expect to see the dust sublimation region and the nucleus directly without obscuration. Here we present the near-IR interferometric…

Directional clustering can be expected in cosmic ray observations due to purely statistical fluctuations for sources distributed randomly in the sky. We develop an analytic approach to estimate the probability of random cluster…

Astrophysics · Physics 2008-11-26 Haim Goldberg , Thomas J. Weiler

Mid-infrared imaging at resolutions of 300 mas of the central kpc region of 13 nearby, well-known active galaxies is presented. The bulk of the mid-IR emission is concentrated on an unresolved central source within a size of less than 5 to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 J. Reunanen , M. A. Prieto , R. Siebenmorgen

Many different physical processes have been suggested to explain the prompt gamma-ray emission in gamma-ray bursts (GRBs). Although there are examples of both bursts with photospheric and synchrotron emission origins, these distinct…

High Energy Astrophysical Phenomena · Physics 2018-02-07 Zeynep Acuner , Felix Ryde

Angular broadening observations of compact radio sources provide a powerful method for probing the solar corona and solar wind. Such observations enable studies of the phase structure function, turbulence amplitude, intermediate-scale…

Airy beams are known for displaying shape invariance and self-acceleration along the transverse direction while they propagate forwards. Although these properties could be associated with the beam coherence, it has been revealed that they…

Quantum Physics · Physics 2022-11-17 R. Martínez-Herrero , A. S. Sanz

In order to study the ram-pressure interaction between radio galaxies and the intracluster medium, we analyse a sample of 208 highly-bent narrow-angle tail radio sources (NATs) in clusters, detected by the LOFAR Two-metre Sky Survey. For…

Astrophysics of Galaxies · Physics 2021-07-14 K de Vos , N. A. Hatch , M. R. Merrifield , B. Mingo

Atmospheric Cherenkov telescopes rely on the Earth's atmosphere as part of the detector. The presence of clouds affects observations and can introduce biases if not corrected for. Correction methods typically require an atmospheric profile,…

Instrumentation and Methods for Astrophysics · Physics 2024-04-03 Julian Sitarek , Mario Pecimotika , Natalia Żywucka , Dorota Sobczyńska , Abelardo Moralejo , Dario Hrupec

One of the most intriguing results from the gamma-ray instruments in orbit has been the detection of powerful flares from the Crab Nebula. These flares challenge our understanding of pulsar wind nebulae and models for particle acceleration.…

Quasars show a remarkable degree of atomic emission line-broadening, an observational feature which, in conjunction with a radial distance estimate for this emission from the nucleus is often used to infer the mass of the central…

A most desirable feature of a standard candle to estimate astronomical distances is robustness against changes in metallicity and age. It is argued that the radii of main sequence stars with spectral types from solar to A0 show predictable…

Astrophysics · Physics 2009-10-31 Carlos Allende Prieto

Using ALMA observations of $^{12}$CO(2-1), $^{28}$SiO(5-4) and $^{32}$SO$_2$(16$_{6,10}$-17$_{5,13}$) emissions of the circumstellar envelope of AGB star EP Aqr, we describe the morpho-kinematics governing the nascent wind. Main results…

Solar and Stellar Astrophysics · Physics 2019-05-15 P. Tuan-Anh , D. T. Hoai , P. T. Nhung , P. Darriulat , P. N. Diep , T. Le Bertre , N. T. Phuong , T. T. Thai , J. M. Winters
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