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Title: On the puzzling high-energy pulsations of the energetic radio-quiet γ-ray pulsar J1813–1246

We have analyzed the new deep XMM-Newton and Chandra observations of the energetic, radio-quiet pulsar J1813–1246. The X-ray spectrum is nonthermal, very hard, and absorbed. Based on spectral considerations, we propose that J1813 is located at a distance further than 2.5 kpc. J1813 is highly pulsed in the X-ray domain, with a light curve characterized by two sharp, asymmetrical peaks, separated by 0.5 in phase. We detected no significant X-ray spectral changes during the pulsar phase. We extended the available Fermi ephemeris to five years. We found two glitches. The γ-ray light curve is characterized by two peaks, separated by 0.5 in phase, with a bridge in between and no off-pulse emission. The spectrum shows clear evolution in phase, being softer at the peaks and hardening toward the bridge. Surprisingly, both X-ray peaks lag behind the γ-ray ones by a quarter of phase. We found a hint of detection in the 30-500 keV band with INTEGRAL, which is consistent with the extrapolation of both the soft X-ray and γ-ray emission of J1813. The unique X-ray and γ-ray phasing suggests a singular emission geometry. We discuss some possibilities within the current pulsar emission models. Finally, we develop an alternative geometrical modelmore » where the X-ray emission comes from polar cap pair cascades.« less
Authors:
; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via E. Bassini 15, I-20133 Milano (Italy)
  2. Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  3. Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)
  4. Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong)
  5. Laboratoire AIM, CEA-IRFU/CNRS/Universit Paris Diderot, Service d'Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France)
Publication Date:
OSTI Identifier:
22370220
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMIC GAMMA BURSTS; COSMIC RADIO SOURCES; DETECTION; DISTANCE; EMISSION; EXTRAPOLATION; GAMMA RADIATION; KEV RANGE; NEUTRONS; PULSARS; SOFT X RADIATION; STAR EVOLUTION; STARS; VISIBLE RADIATION; X-RAY SPECTRA