An Ultraluminous X-ray Source Powered by An Accreting Neutron Star
An Ultraluminous X-ray Source Powered by An Accreting Neutron Star
Ultraluminous X-ray sources (ULX) are off-nuclear point sources in nearby galaxies whose X-ray luminosity exceeds the theoretical maximum for spherical infall (the Eddington limit) onto stellar-mass black holes. Their luminosity ranges from $10^{40}$ erg s$^{-1} < L_X$(0.5 - 10 keV) $<10^{40}$ erg s$^{-1}$. Since 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 ($L_X$ > $10^{40}$ erg s$^{-1}$), which require black hole masses MBH >50 solar masses and/or significant departures from the standard thin disk accretion that powers bright Galactic X-ray binaries. Here we report broadband X-ray observations of the nuclear region of the galaxy M82, which contains two bright ULXs. The observations reveal pulsations of average period 1.37 s with 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 $L_X$(3 - 30 keV) = $4.9 \times 10^{39}$ erg s$^{-1}$. The pulsating source is spatially coincident with a variable ULX which can reach $L_X$ (0.3 - 10 keV) = $1.8 \times 10^{40}$ erg s$^{-1}$. This association implies a luminosity ~100 times the Eddington limit for a 1.4 solar mass object, or more than ten times brighter than any known accreting pulsar. This finding implies that neutron stars may not be rare in the ULX population, and it challenges physical models for the accretion of matter onto magnetized compact objects.
M. Bachetti、F. A. Harrison、A. C. Fabian、J. M. Miller、D. Chakrabarty、W. W. Zhang、N. A. Webb、D. Barret、A. Hornschemeier、C. J. Hailey、T. Maccarone、V. Kaspi、W. W. Craig、F. F¨1rst、S. R. Kulkarni、S. E. Boggs、S. P. Tendulkar、A. Beloborodov、V. Rana、B. W. Grefenstette、J. Tomsick、F. E. Christensen、D. J. Walton、D. Stern
Universit¨| de Toulouse, UPS-OMP, IRAP, F-31400 Toulouse, FranceCahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USAInstitute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UKDepartment of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042, USAMIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USANASA Goddard Space Flight Center, Greenbelt, MD 20771, USAUniversit¨| de Toulouse, UPS-OMP, IRAP, F-31400 Toulouse, FranceUniversit¨| de Toulouse, UPS-OMP, IRAP, F-31400 Toulouse, FranceNASA Goddard Space Flight Center, Greenbelt, MD 20771, USAColumbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USADepartment of Physics, Texas Tech University, Lubbock, TX 79409, USADepartment of Physics, McGill University, Montreal, Quebec, H3A 2T8, CanadaLawrence Livermore National Laboratory, Livermore, CA 94550, USACahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USACahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USADTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby, DenmarkCahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USAPhysics Department, Columbia University. 538 W 120th Street, New York, NY 10027, USA 6Space Sciences Laboratory, University of California, Berkeley, CA 94720, USACahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USACahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USAUniversit¨| de Toulouse, UPS-OMP, IRAP, F-31400 Toulouse, FranceDTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby, DenmarkCahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USAJet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
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M. Bachetti,F. A. Harrison,A. C. Fabian,J. M. Miller,D. Chakrabarty,W. W. Zhang,N. A. Webb,D. Barret,A. Hornschemeier,C. J. Hailey,T. Maccarone,V. Kaspi,W. W. Craig,F. F¨1rst,S. R. Kulkarni,S. E. Boggs,S. P. Tendulkar,A. Beloborodov,V. Rana,B. W. Grefenstette,J. Tomsick,F. E. Christensen,D. J. Walton,D. Stern.An Ultraluminous X-ray Source Powered by An Accreting Neutron Star[EB/OL].(2014-10-14)[2025-08-10].https://arxiv.org/abs/1410.3590.点此复制
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