Статья

<i>NuSTAR</i> DISCOVERY OF A 3.76 s TRANSIENT MAGNETAR NEAR SAGITTARIUS A*

Kaya MoriColumbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA; [email protected]E. V. GotthelfColumbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA; [email protected]Shuo ZhangColumbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA; [email protected]Hongjun AnDepartment of Physics, McGill University, Montreal, QC H3A 2T8, CanadaFrederick K. BaganoffKavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USANicolas M. BarrièreSpace Sciences Laboratory, University of California, Berkeley, CA 94720, USAAndrei M. BeloborodovColumbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA; [email protected]Steven E. BoggsSpace Sciences Laboratory, University of California, Berkeley, CA 94720, USAFinn E. ChristensenDTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, 2800 Lyngby, DenmarkWilliam W. CraigSpace Sciences Laboratory, University of California, Berkeley, CA 94720, USAFrançois DufourDepartment of Physics, McGill University, Montreal, QC H3A 2T8, CanadaBrian W. GrefenstetteCahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USACharles J. HaileyColumbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA; [email protected]Fiona A. HarrisonCahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USAJaesub HongHarvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USAV. M. KaspiDepartment of Physics, McGill University, Montreal, QC H3A 2T8, CanadaJ. A. KenneaDepartment of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USAKristin K. MadsenCahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USAC. B. MarkwardtNASA Goddard Space Flight Center, Greenbelt, MD 20771, USAMelania NynkaColumbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA; [email protected]Daniel SternJet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USAJohn A. TomsickSpace Sciences Laboratory, University of California, Berkeley, CA 94720, USAWilliam W. ZhangNASA Goddard Space Flight Center, Greenbelt, MD 20771, USA

2013en

ABI

Аннотация

We report the discovery of 3.76 s pulsations from a new burst source near Sgr A^* observed by the NuSTAR observatory. The strong signal from SGR J1745–29 presents a complex pulse profile modulated with pulsed fraction 27% ± 3% in the 3-10 keV band. Two observations spaced nine days apart yield a spin-down rate of Ṗ =(6.5 ± 1.4) × 10^(–12). This implies a magnetic field B = 1.6 × 10^(14) G, spin-down power Ė =5 × 10^(33) erg s^(–1), and characteristic age P/2Ṗ =9 × 10^3 yr for the rotating dipole model. However, the current Ṗ may be erratic, especially during outburst. The flux and modulation remained steady during the observations and the 3-79 keV spectrum is well fitted by a combined blackbody plus power-law model with temperature kT_(BB) = 0.96 ± 0.02 keV and photon index Γ = 1.5 ± 0.4. The neutral hydrogen column density (N_H ~ 1.4 × 10^(23) cm^(–2)) measured by NuSTAR and Swift suggests that SGR J1745–29 is located at or near the Galactic center. The lack of an X-ray counterpart in the published Chandra survey catalog sets a quiescent 2-8 keV luminosity limit of L_x ≾ 10^(32) erg s^(–1). The bursting, timing, and spectral properties indicate a transient magnetar undergoing an outburst with 2-79 keV luminosity up to 3.5 × 10^(35) erg s^(–1) for a distance of 8 kpc. SGR J1745–29 joins a growing subclass of transient magnetars, indicating that many magnetars in quiescence remain undetected in the X-ray band or have been detected as high-B radio pulsars. The peculiar location of SGR J1745–29 has important implications for the formation and dynamics of neutron stars in the Galactic center region.

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Идентификаторы

DOI: 10.1088/2041-8205/770/2/l23

Цитирования и источники

Цитирований: 14Использованных источников: 0

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