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Related papers: The Secular Decrease of the Crab Nebula at 927 and…

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The Crab Nebula was detected with the Milagro experiment at a statistical significance of 17 standard deviations over the lifetime of the experiment. The experiment was sensitive to approximately 100 GeV - 100 TeV gamma ray air showers by…

The HEGRA system of imaging atmospheric Cherenkov telescopes provides for specially selected classes of events an angular resolution of better than 3'. By comparing the measured angular distribution of TeV gamma rays from the Crab Nebula…

Astrophysics · Physics 2007-05-23 HEGRA Collaboration , F. Aharonian

We have analysed the radio fluxes for 264 planetary nebulae for which reliable measurements of fluxes at 1.4 and 5 GHz, and of nebular diameters are available. For many of the investigated nebulae the optical thickness is important,…

Astrophysics · Physics 2009-11-06 N. Siodmiak , R. Tylenda

We study properties of the superorbital modulation of the X-ray emission of Cyg X-1. We find that it has had a stable period of about 300 d in soft and hard X-rays and in radio since 2005 until at least 2010, which is about double the…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Andrzej A. Zdziarski , Guy G. Pooley , Gerald K. Skinner

We have constructed MOCASSIN photoionization plus dust radiative transfer models for the Crab Nebula core-collapse supernova (CCSN) remnant, using either smooth or clumped mass distributions, in order to determine the chemical composition…

Astrophysics of Galaxies · Physics 2015-06-23 P. J. Owen , M. J. Barlow

We show that the mysterious, rapidly variable emission at ~400 MeV observed from the Crab Nebula by the AGILE and Fermi experiments could be the result of a sudden drop in the mass-loading of the pulsar wind. The current required to…

High Energy Astrophysical Phenomena · Physics 2017-11-29 John G. Kirk , Gwenael Giacinti

We present analysis of the rate of giant radio pulses (GPs) emission from the Crab pulsar (B0531+21). Results of our 9 years daily observations with the Large Phased Array radio telescope of Pushchino Radio Astronomy Observatory at 111 MHz…

High Energy Astrophysical Phenomena · Physics 2020-05-19 A. N. Kazantsev , V. A. Potapov , M. S. Pshirkov , B. Ya. Losovskii

The GRANAT group (R. Sunyaev {\it et al.\/}, Central Bureau of Astronomical Telegrams, International Astronomical Union, Circular No.~5481) recently reported the observation of a $(545 \pm 11)$ keV line in the spectrum of the Crab Nebula.…

High Energy Physics - Phenomenology · Physics 2007-05-23 Myron Bander , H. R. Rubinstein

We report on observations of the polarization of optical and {\gamma}-ray photons from the Crab nebula and pulsar system using the Galway Astronomical Stokes Polarimeter (GASP), the Hubble Space Telescope/Advanced Camera for Surveys…

High Energy Astrophysical Phenomena · Physics 2016-01-27 Paul Moran , Gillian Kyne , Christian Gouiffes , 3 , Philipe Laurent , Gregg Hallinan , Michael Redfern , Andrew Shearer

The Crab nebula is widely used as a polarization angle calibrator for single-dish radio observations because of its brightness, high degree of linear polarization, and well-known polarization angle over a wide frequency range. However, the…

Astrophysics of Galaxies · Physics 2023-01-25 Minchul Kam , Sascha Trippe , Do-Young Byun , Jongho Park , Sincheol Kang , Naeun Shin , Sang-Sung Lee , Taehyun Jung

Since 2009, several rapid and bright flares have been observed at high energies (>100 MeV) from the direction of the Crab Nebula. Several hypotheses have been put forward to explain this phenomenon, but the origin is still unclear. The…

High Energy Astrophysical Phenomena · Physics 2022-10-11 Enrique Mestre , Emma de Ona Wilhelmi , Dmitry Khangulyan , Roberta Zanin , Fabio Acero , Diego F. Torres

A model of an accelerated expansion of the Crab Nebula powered by the spinning-down Crab pulsar is proposed, in which time dependence of the acceleration is connected with evolution of pulsar luminosity. Using recent observational data, we…

Astrophysics · Physics 2011-05-23 M. Bejger , P. Haensel

We present deep images of a region around the Crab nebula made with the VLA, utilizing new imaging and deconvolution algorithms in a search for a faint radio shell. The existence of a high-velocity, hydrogen-rich envelope has been predicted…

Astrophysics · Physics 2009-10-28 D. A. Frail , N. E. Kassim , T. J. Cornwell , W. M. Goss

We present a systematic study of the recently reported anti-correlation between X-ray flux and photon index ($\Gamma$) in the Crab Nebula, using archival RXTE/PCA (3 - 50 keV), RXTE/HEXTE (20 - 100 keV), and NuSTAR (3 - 78 keV)…

High Energy Astrophysical Phenomena · Physics 2025-06-24 Debjit Chatterjee , Hsiang-Kuang Chang , Dipak Debnath , Koothodil Abhijith Augustine , Tzu-Hsuan Lin

From existing broad-band images obtained with the Hubble Space Telescope, we located 92 globules, for which we derived positions, dimensions, orientations, extinctions, masses, proper motions, and their distributions. The globules have mean…

Solar and Stellar Astrophysics · Physics 2017-03-15 Tiia Grenman , Gösta F. Gahm , Erik Elfgren

Accurate calibration of data is essential for the current generation of CMB experiments. Using data from the Very Small Array (VSA), we describe procedures which will lead to an accuracy of 1 percent or better for experiments such as the…

Strong gamma-ray flares from the Crab Nebula have been recently discovered by AGILE and confirmed by Fermi-LAT. We study here the spectral evolution in the gamma-ray energy range above 50 MeV of the September 2010 flare that was…

High Energy Astrophysical Phenomena · Physics 2015-05-27 V. Vittorini , M. Tavani , G. Pucella , I. Donnarumma

The CAT imaging telescope, recently built on the site of the former solar plant Themis (French Pyrenees), observed gamma-rays from the Crab nebula from October 1996 to March 1997. This steady source, often considered as the standard candle…

We analyzed four epochs of beamformed EVN data of the Crab Pulsar at 1658.49 MHz. With the high sensitivity resulting from resolving out the Crab Nebula, we are able to detect even the faint high-frequency components in the folded profile.…

High Energy Astrophysical Phenomena · Physics 2023-09-18 Rebecca Lin , Marten H. van Kerkwijk

We analyze the effect of polarized diffuse emission in the calibration of wide-beam mm-wave polarimeters, when using the Crab Nebula as a reference source for both polarized brightness and polarization angle. We show that, for CMB…

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