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Title: HERSCHEL AND SPITZER OBSERVATIONS OF SLOWLY ROTATING, NEARBY ISOLATED NEUTRON STARS

Abstract

Supernova fallback disks around neutron stars have been suspected to influence the evolution of the diverse neutron star populations. Slowly rotating neutron stars are the most promising places to find such disks. Searching for the cold and warm debris of old fallback disks, we carried out Herschel PACS (70 μm, 160 mu m) and Spitzer IRAC (3.6 μm, 4.5 μm) observations of eight slowly rotating (P ≈ 3-11 s) nearby (<1 kpc) isolated neutron stars. Herschel detected 160 μm emission (>5σ) at locations consistent with the positions of the neutron stars RX J0806.4-4123 and RX J2143.0+0654. No other significant infrared emission was detected from the eight neutron stars. We estimate probabilities of 63%, 33%, and 3% that, respectively, none, one, or both Herschel PACS 160 μm detections are unrelated excess sources due to background source confusion or an interstellar cirrus. If the 160 μm emission is indeed related to cold (10-22 K) dust around the neutron stars, this dust is absorbing and re-emitting ∼10% to ∼20% of the neutron stars' X-rays. Such high efficiencies would be at least three orders of magnitude larger than the efficiencies of debris disks around nondegenerate stars. While thin dusty disks around the neutron starsmore » can be excluded as counterparts of the 160 μm emission, dusty asteroid belts constitute a viable option.« less

Authors:
;  [1];  [2];  [3]
  1. Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)
  2. Sternberg Astronomical Institute, Lomonosov Moscow State University, Moscow 119992 (Russian Federation)
  3. Max Planck Institute for Astronomy, Königsstuhl 17, D-69117 Heidelberg (Germany)
Publication Date:
OSTI Identifier:
22340141
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal, Supplement Series; Journal Volume: 215; 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; ASTEROIDS; COSMIC DUST; DETECTION; EMISSION; NEUTRON STARS; PROBABILITY; STAR EVOLUTION; X RADIATION

Citation Formats

Posselt, B., Pavlov, G. G., Popov, S., and Wachter, S., E-mail: posselt@psu.edu. HERSCHEL AND SPITZER OBSERVATIONS OF SLOWLY ROTATING, NEARBY ISOLATED NEUTRON STARS. United States: N. p., 2014. Web. doi:10.1088/0067-0049/215/1/3.
Posselt, B., Pavlov, G. G., Popov, S., & Wachter, S., E-mail: posselt@psu.edu. HERSCHEL AND SPITZER OBSERVATIONS OF SLOWLY ROTATING, NEARBY ISOLATED NEUTRON STARS. United States. doi:10.1088/0067-0049/215/1/3.
Posselt, B., Pavlov, G. G., Popov, S., and Wachter, S., E-mail: posselt@psu.edu. 2014. "HERSCHEL AND SPITZER OBSERVATIONS OF SLOWLY ROTATING, NEARBY ISOLATED NEUTRON STARS". United States. doi:10.1088/0067-0049/215/1/3.
@article{osti_22340141,
title = {HERSCHEL AND SPITZER OBSERVATIONS OF SLOWLY ROTATING, NEARBY ISOLATED NEUTRON STARS},
author = {Posselt, B. and Pavlov, G. G. and Popov, S. and Wachter, S., E-mail: posselt@psu.edu},
abstractNote = {Supernova fallback disks around neutron stars have been suspected to influence the evolution of the diverse neutron star populations. Slowly rotating neutron stars are the most promising places to find such disks. Searching for the cold and warm debris of old fallback disks, we carried out Herschel PACS (70 μm, 160 mu m) and Spitzer IRAC (3.6 μm, 4.5 μm) observations of eight slowly rotating (P ≈ 3-11 s) nearby (<1 kpc) isolated neutron stars. Herschel detected 160 μm emission (>5σ) at locations consistent with the positions of the neutron stars RX J0806.4-4123 and RX J2143.0+0654. No other significant infrared emission was detected from the eight neutron stars. We estimate probabilities of 63%, 33%, and 3% that, respectively, none, one, or both Herschel PACS 160 μm detections are unrelated excess sources due to background source confusion or an interstellar cirrus. If the 160 μm emission is indeed related to cold (10-22 K) dust around the neutron stars, this dust is absorbing and re-emitting ∼10% to ∼20% of the neutron stars' X-rays. Such high efficiencies would be at least three orders of magnitude larger than the efficiencies of debris disks around nondegenerate stars. While thin dusty disks around the neutron stars can be excluded as counterparts of the 160 μm emission, dusty asteroid belts constitute a viable option.},
doi = {10.1088/0067-0049/215/1/3},
journal = {Astrophysical Journal, Supplement Series},
number = 1,
volume = 215,
place = {United States},
year = 2014,
month =
}
  • The nearby isolated neutron stars (INSs) are a group of seven relatively slowly rotating neutron stars that show thermal X-ray spectra, most with broad absorption features. They are interesting both because they may allow one to determine fundamental neutron-star properties by modeling their spectra, and because they appear to be a large fraction of the overall neutron-star population. Here, we describe a series of XMM -Newton observations of the nearby INS RX J0806.4-4123, taken as part of larger program of timing studies. From these, we limit the spin-down rate to nu-dot=(-4.3+-2.3)x10{sub -16}Hz s{sup -1}. This constrains the dipole magnetic fieldmore » to be <3.7 x 10{sup 13} G at 2sigma, significantly less than the field of approx10{sup 14} G implied by simple models for the X-ray absorption found at 0.45 keV. We confirm that the spectrum is thermal and stable (to within a few percent), but find that the 0.45 keV absorption feature is broader and more complex than previously thought. Considering the population of INSs, we find that magnetic field decay from an initial field of approx<3 x 10{sup 14} G accounts most naturally for their timing and spectral properties, both qualitatively and in the context of the models for field decay of Pons and collaborators.« less
  • The origin of the slowly pulsing X-ray sources is considered. It is shown that tidal forces in a pre-supernova binary system will lead to synchronization of the stellar rotation with the orbital period. Consideration of the structure of the presupernova star then indicates that X-ray periods of the correct order of magnitude will be produced in these systems. (AIP)