Phase-dependent spectral variability in 4U 1907 + 09

Mallory Roberts, Peter F. Michelson, Denis A. Leahy, Tony A. Hall, John P. Finley, Lynn R. Cominsky, Radhika Srinivasan

Research output: Contribution to journalArticle

Abstract

We report on ASCA, RXTE, and archival observations of the high-mass X-ray binary pulsar 4U 1907+09. Spectral measurements of the absorption and flux were made at all phases of the X-ray pulsar orbit, including the first spectral measurements of an extended period of low flux during two of the ASCA observations. We find that a simple spherical wind model can fit the time-averaged light curve as measured by the RXTE All-Sky Monitor but does not fit the observed changes in the absorption column or account for the existence of the phase-locked secondary flare. An additional model component consisting of a trailing stream can account for the variations in column depth. However, these models favor a high inclination angle for the system, suggesting a companion mass more consistent with an identification as a Be star. In this case, an equatorially enhanced wind and inclined neutron star orbit may be a more appropriate interpretation of the data.

Original languageEnglish (US)
Pages (from-to)967-977
Number of pages11
JournalAstrophysical Journal
Volume555
Issue number2 PART 1
DOIs
StatePublished - Jul 10 2001

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X Ray Timing Explorer
pulsars
orbits
flares
neutron stars
light curve
inclination
sky
monitors
x rays
stars

Keywords

  • Stars: emission-line, Be
  • Stars: mass loss
  • X-rays: stars

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Roberts, M., Michelson, P. F., Leahy, D. A., Hall, T. A., Finley, J. P., Cominsky, L. R., & Srinivasan, R. (2001). Phase-dependent spectral variability in 4U 1907 + 09. Astrophysical Journal, 555(2 PART 1), 967-977. https://doi.org/10.1086/321487

Phase-dependent spectral variability in 4U 1907 + 09. / Roberts, Mallory; Michelson, Peter F.; Leahy, Denis A.; Hall, Tony A.; Finley, John P.; Cominsky, Lynn R.; Srinivasan, Radhika.

In: Astrophysical Journal, Vol. 555, No. 2 PART 1, 10.07.2001, p. 967-977.

Research output: Contribution to journalArticle

Roberts, M, Michelson, PF, Leahy, DA, Hall, TA, Finley, JP, Cominsky, LR & Srinivasan, R 2001, 'Phase-dependent spectral variability in 4U 1907 + 09', Astrophysical Journal, vol. 555, no. 2 PART 1, pp. 967-977. https://doi.org/10.1086/321487
Roberts M, Michelson PF, Leahy DA, Hall TA, Finley JP, Cominsky LR et al. Phase-dependent spectral variability in 4U 1907 + 09. Astrophysical Journal. 2001 Jul 10;555(2 PART 1):967-977. https://doi.org/10.1086/321487
Roberts, Mallory ; Michelson, Peter F. ; Leahy, Denis A. ; Hall, Tony A. ; Finley, John P. ; Cominsky, Lynn R. ; Srinivasan, Radhika. / Phase-dependent spectral variability in 4U 1907 + 09. In: Astrophysical Journal. 2001 ; Vol. 555, No. 2 PART 1. pp. 967-977.
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