Open AccessX‐ray spectral properties of the pulsar EXO 2030+375 during an outburst
Author(s) -
Reig P.,
Coe M. J.
Publication year - 1999
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1999.02179.x
Subject(s) - physics , pulsar , astrophysics , black body radiation , neutron star , spectral line , luminosity , radius , x ray pulsar , cyclotron , power law , radiation , astronomy , nuclear physics , electron , statistics , computer security , mathematics , galaxy , computer science
We present the results of the spectral analysis carried out of the X‐ray pulsar EXO 2030+375. The observations were made using the Rossi X‐ray Timing Explorer (RXTE) satellite. Our study concentrates on the X‐ray characteristics of this source at lower luminosities (L x < 5 × 10 36 erg s ‐1 ) than have previously been observed and in the energy range 2.7‐‐30 keV. The PCA X‐ray continuum spectra can be represented by a model containing two components: a power law with an exponential cut‐off at higher energies and a blackbody. The power‐law component accounts for the high‐energy part of the continuum whereas the blackbody component describes the part of the spectrum below ∼ 10 keV. The radius of the X‐ray emission surface is found to be ∼ 1 km, which agrees with the size of the neutron star polar caps. Our results are compared with higher‐luminosity studies and are seen to agree with trends observed in these previous findings. We also show the first hard X‐ray spectrum (17‐‐65 keV) of EXO 2030+375. A possible spectral feature at ∼ 36 keV is tentatively ascribed to a cyclotron absorption line.