Chandra Observations and Monte Carlo Simulations of the Grain-Scattered Halo of the Binary X-Ray Pulsar 4U 1538-52

Abstract

Properties of the X-ray halo of the eclipsing X-ray pulsar 4U 1538-52 are derived from a 25 ksec observation by the Chandra X-Ray Observatory. Profiles of the halo, compiled in two energy ranges, 2 to 4 keV and 4 to 6 keV, and three time intervals before and after an eclipse immersion, exhibit a three-peak shape. The observed profiles are fitted by the profiles of a simulated halo generated by a Monte Carlo ray-tracing code operating on a model of three discrete clouds and a spectrum of the photons emitted by the source over a period of time extending from 270 ksec before the observation began till it ended. The distances of the two nearer dust clouds are fixed at the distances of the peaks of atomic hydrogen derived from the 21-cm spectrum in the direction of the X-ray source, namely at 1.30 and 2.56 kpc. A good fit is achieved with the source at a distance 4.5 kpc, the distance of the third cloud at 4.05 kpc, the total scattering optical depth of the three clouds equal to 0.159 at 3 keV, and the column density of hydrogen set to 4.6x10^22 cm^-2. With Av=6.5 mag for the binary companion star, QV Nor, the ratio of the scattering optical depth at 3 keV to the visual extinction is 0.0234 mag^-1.

arXiv comment36 pages, 15 figures, 4 tables, abridged version of paper accepted for publication in August 1, 2004 ApJ

References in corpus (4)

• Scattering by Interstellar Dust Grains. II. X-Rays
• Soft X-ray Scattering and Halos from Dust
• The BeppoSAX 0.1 - 100 keV Spectrum of the X-ray Pulsar 4U 1538-52
• X-ray Halos and Large Grains in the Diffuse Interstellar Medium

Cited by in corpus (16)

• The gas-to-extinction ratio and the gas distribution in the Galaxy
• Population of persistent high mass X-ray binaries in the Milky Way
• Clustering between high-mass X-ray binaries and OB associations in the Milky Way
• Distribution of High-Mass X-ray Binaries in the Milky Way
• Distances to Galactic X-ray Binaries with Gaia DR2
• X-ray Spectroscopy of the High Mass X-ray Binary Pulsar Centaurus X-3 over its Binary Orbit
• A giant X-ray dust scattering ring around the black hole transient MAXI J1348-630 discovered with SRG/eROSITA
• The dust-scattered X-ray halo around Swift GRB 050724
• CHANDRA Observations of the X-ray Halo around the Crab Nebula
• Measurements of Cyclotron Features and Pulse Periods in the High-Mass X-Ray Binaries 4U 1538-522 and 4U 1907+09 with INTEGRAL
• The First NuSTAR Observation of 4U 1538-522: Updated Orbital Ephemeris and A Strengthened Case for an Evolving Cyclotron Line Energy
• Direct Extragalactic Distance Determination Using X-Ray Scattering
• Evidence for an Evolving Cyclotron Line Energy in 4U 1538-522
• Geometrical Distance Determination using Type I X-ray Bursts
• Further evidence for natal kick segregation by spectral type in high-mass X-ray binaries
• Spectroscopic modelling of two high-mass X-ray binaries, Cyg X--3 and 4U 1538--522