1999/04/23 by R. I. Hynes, Hynes, R. I., P. A. Charles +7
Engineering · Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #SAS software applications and methods #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9904325
To appear in the Proceedings of the 19th Texas Symposium on Relativistic Astrophysics and Cosmology (CD-ROM Edn.) 11 pages, 9 postscript figs. included. Uses texas.sty (included)
arxiv created 1999/04/23 · openalex publication_date 1999/04/23 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present time-resolved spectroscopy of the soft X-ray transient XTE J2123-058 in outburst. Spectral coverage of 3700-6700A was achieved spanning two orbits of the binary. The strongest emission lines are HeII 4686A and CIII/NIII 4640A (Bowen blend). Other weak emission lines of HeII and CIV are present and Balmer lines show a complex structure, possibly contaminated by HeII. HeII 4686A and CIII/NIII 4640A show different orbital light curves indicating an origin in different regions. HeII 4686A profiles show a complex multiple S-wave structure. Doppler tomography reveals this emission is not associated with the companion star, and occurs at velocities too low for Keplerian disk material. It can possibly be associated with overflowing or splashing stream material. The optical spectrum approximates a steep blue power-law, consistent with emission on the Rayleigh-Jeans tail of a black body spectrum. Orbital modulations show no wavelength dependence; this is as expected if both disk and companion star are hot enough for the peak of their spectral energy distributions to be in the UV. The hot continuum and presence of high-excitation emission lines indicate strong X-ray heating.