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Title: The Vela pulsar with an active fallback disk

Fallback disks are expected to form around young neutron stars. The presence of these disks can be revealed by their blackbody spectrum in the infrared, optical, and UV bands. We present a re-reduction of the archival optical and infrared data of the Vela pulsar, together with the existing infrared and UV spectrum of Vela, and model their unpulsed components with the blackbody spectrum of a supernova debris disk. We invoke the quiescent disk solution of Sunyaev and Shakura for the description of the disk in the propeller stage and find the inner radius of the disk to be inside the light cylinder radius. We perform a high-resolution X-ray analysis with XMM-Newton and find a narrow absorption feature at 0.57 keV that can be interpreted as the K {sub α} line of He-like oxygen (O VII). The strength of the line indicates an element over-abundance in our line of sight exceeding the amounts that would be expected from interstellar medium. The spectral feature may originate from the pulsar wind nebula and may be partly caused by the reprocessed X-ray radiation by the fallback disk. We discuss the lower-than-three braking index of Vela as partially due to the contribution of the propellermore » torques. Our results suggest that the pulsar mechanism can work simultaneously with the propeller processes and that the debris disks can survive the radiation pressure for at least ∼10{sup 4} yr. As Vela is a relatively close object, and a prototypical pulsar, the presence of a disk, if confirmed, may indicate the ubiquity of debris disks around young neutron stars.« less
Authors:
;  [1] ; ; ; ;  [2] ;  [3]
  1. Faculty of Science and Letters, Department of Physics, İstanbul Technical University, Maslak 34469, İstanbul (Turkey)
  2. Astrophysikalisches Institut und Universitäts-Sternwarte, Universität Jena, Schillergäßchen 2-3, 07745 Jena (Germany)
  3. Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, D-72076 Tübingen (Germany)
Publication Date:
OSTI Identifier:
22370195
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 796; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ACCRETION DISKS; ELEMENT ABUNDANCE; KEV RANGE; NEBULAE; NEUTRON STARS; NEUTRONS; OXYGEN; PULSARS; RADIATION PRESSURE; RESOLUTION; STELLAR WINDS; ULTRAVIOLET SPECTRA; VISIBLE RADIATION; X RADIATION