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  • 1
    Publication Date: 2014-10-10
    Description: The majority of ultraluminous X-ray sources are point sources that are spatially offset from the nuclei of nearby galaxies and whose X-ray luminosities exceed the theoretical maximum for spherical infall (the Eddington limit) onto stellar-mass black holes. Their X-ray luminosities in the 0.5-10 kiloelectronvolt energy band range from 10(39) to 10(41) ergs per second. Because higher masses imply less extreme ratios of the luminosity to the isotropic Eddington limit, theoretical models have focused on black hole rather than neutron star systems. The most challenging sources to explain are those at the luminous end of the range (more than 10(40) ergs per second), which require black hole masses of 50-100 times the solar value or significant departures from the standard thin disk accretion that powers bright Galactic X-ray binaries, or both. Here we report broadband X-ray observations of the nuclear region of the galaxy M82 that reveal pulsations with an average period of 1.37 seconds and a 2.5-day sinusoidal modulation. The pulsations result from the rotation of a magnetized neutron star, and the modulation arises from its binary orbit. The pulsed flux alone corresponds to an X-ray luminosity in the 3-30 kiloelectronvolt range of 4.9 x 10(39) ergs per second. The pulsating source is spatially coincident with a variable source that can reach an X-ray luminosity in the 0.3-10 kiloelectronvolt range of 1.8 x 10(40) ergs per second. This association implies a luminosity of about 100 times the Eddington limit for a 1.4-solar-mass object, or more than ten times brighter than any known accreting pulsar. This implies that neutron stars may not be rare in the ultraluminous X-ray population, and it challenges physical models for the accretion of matter onto magnetized compact objects.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bachetti, M -- Harrison, F A -- Walton, D J -- Grefenstette, B W -- Chakrabarty, D -- Furst, F -- Barret, D -- Beloborodov, A -- Boggs, S E -- Christensen, F E -- Craig, W W -- Fabian, A C -- Hailey, C J -- Hornschemeier, A -- Kaspi, V -- Kulkarni, S R -- Maccarone, T -- Miller, J M -- Rana, V -- Stern, D -- Tendulkar, S P -- Tomsick, J -- Webb, N A -- Zhang, W W -- England -- Nature. 2014 Oct 9;514(7521):202-4. doi: 10.1038/nature13791.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Universite de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planetologie, 9, Avenue du Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France [2] CNRS, Institut de Recherche en Astrophysique et Planetologie, 9, Avenue du Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France. ; Cahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USA. ; MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. ; Physics Department, Columbia University, 538 West 120th Street, New York, New York 10027, USA. ; Space Sciences Laboratory, University of California, Berkeley, California 94720, USA. ; DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby, Denmark. ; Lawrence Livermore National Laboratory, Livermore, California 94550, USA. ; Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK. ; Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA. ; NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA. ; Department of Physics, McGill University, Montreal, Quebec H3A 2T8, Canada. ; Department of Physics, Texas Tech University, Lubbock, Texas 79409, USA. ; Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, Michigan 48109-1042, USA. ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25297433" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The survey, described briefly in ref. 1, has been searching the southern sky for millisecond and other low-luminosity pulsars since July 1991, using the Parkes 64-m radiotelescope at 430 MHz. A very strong signal was seen in data taken on February 13,1992 and observations taken July 11 1992 ...
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Following the SAS-2 and COS-B high-energy y-ray observations of the Crab (0531 + 21) and Vela (0833-45) pulsars1'2, searches were made for additional y-ray pulsars3'5. No other positive results were then found, but calculations have indicated that y-ray emission is likely from other ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 381 (1996), S. 584-586 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Radio timing observations7 made not long after the discovery of PSR J0045 - 73199 showed that the minimum mass of the pulsar companion is 4 solar masses (4M0), and optical observations revealed a 16-mag main-sequence B star near the pulsar timing position. The association was confirmed by the ...
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillian Magazines Ltd.
    Nature 419 (2002), S. 142-144 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Anomalous X-ray pulsars (AXPs) are a class of rare X-ray emitting pulsars whose energy source has been perplexing for some 20 years. Unlike other X-ray emitting pulsars, AXPs cannot be powered by rotational energy or by accretion of matter from a binary companion star, hence the designation ...
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe a flexible, inexpensive data acquisition system built for high-precision timing observations of pulsars. The system is designed to interface with a wide variety of radio telescope receiver back ends; it permits standardized measurement techniques and data formats in work carried out at a number of different observatories. Copies of the basic "Mark III'' system are now in regular use at the Arecibo Observatory, Green Bank, and the Very Large Array. We describe the specifications, hardware, and software implementation of the system, and briefly outline some of its current applications.
    Type of Medium: Electronic Resource
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