Optical-ultraviolet spectrum and proper motion of the middle-aged pulsar B1055-52

R. P. Mignani, George Pavlov, O. Kargaltsev

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

PSR B1055-52 is a middle-aged (τ = 535 kyr) radio, X-ray, and γ-ray pulsar showing X-ray thermal emission from the neutron star (NS) surface. A candidate optical counterpart to PSR B1055-52 was proposed by Mignani and coworkers based on Hubble Space Telescope (HST) observations performed in 1996, in one spectral band only. We report on HST observations of this field carried out in 2008, in four spectral bands. The astrometric and photometric analyses of these data confirm the identification of the proposed candidate as the pulsar's optical counterpart. Similar to other middle-aged pulsars, its optical-UV spectrum can be described by the sum of a power-law (PLO) component (Fv α?-αO), presumably emitted from the pulsar magnetosphere, and a Rayleigh-Jeans (RJ) component emitted from the NS surface. The spectral index of the PLO component, αO = 1.05 ± 0.34, is larger than for other pulsars with optical counterparts. The RJ component, with a brightness temperature T O = (0.66 ± 0.10)d2350 R O,13-2 MK (where d350 and RO, 13 are the distance to the pulsar in units of 350 pc and the radius of the emitting area in units of 13 km, respectively), shows a factor of 4 excess with respect to the extrapolation of the X-ray thermal component into the UV-optical. This hints that the RJ component is emitted from a larger, colder area, and suggests that the distance to the pulsar is smaller than previously thought. From absolute astrometry of the HST images, we measured the pulsar coordinates with a position accuracy of 0″.f 15. From comparison with previous observations, we measured the pulsar proper motion, μ = 42 ± 5 mas yr-1, which corresponds to a transverse velocity Vt = (70 ± 8) d350 km s-1.

Original languageEnglish (US)
Pages (from-to)1635-1643
Number of pages9
JournalAstrophysical Journal
Volume720
Issue number2
DOIs
StatePublished - Sep 10 2010

Fingerprint

ultraviolet spectra
proper motion
pulsars
optical spectrum
Hubble Space Telescope
brightness temperature
magnetosphere
power law
spectral bands
radio
neutron stars
pulsar magnetospheres
x rays
astrometry
thermal emission
extrapolation
rays
spectral band
radii

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Mignani, R. P. ; Pavlov, George ; Kargaltsev, O. / Optical-ultraviolet spectrum and proper motion of the middle-aged pulsar B1055-52. In: Astrophysical Journal. 2010 ; Vol. 720, No. 2. pp. 1635-1643.
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Optical-ultraviolet spectrum and proper motion of the middle-aged pulsar B1055-52. / Mignani, R. P.; Pavlov, George; Kargaltsev, O.

In: Astrophysical Journal, Vol. 720, No. 2, 10.09.2010, p. 1635-1643.

Research output: Contribution to journalArticle

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