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Pulsations in the Ultraviolet and X-Ray Spectra of VELA X-1

1996; IOP Publishing; Volume: 465; Linguagem: Inglês

10.1086/177477

1538-4357

Bram Boroson, Richard McCray, T. R. Kallman, F. Nagase,

Stellar, planetary, and galactic studies

view Abstract Citations (10) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Pulsations in the Ultraviolet and X-Ray Spectra of VELA X-1 Boroson, Bram ; McCray, Richard ; Kallman, Timothy ; Nagase, Fumiaki Abstract In simultaneous observations with the Faint Object Spectrograph aboard the Hubble Space Telescope and the large-area counters aboard Ginga, we obtained time-resolved ultraviolet and X-ray spectra of the X-ray binary HD 77581/4U 0900-40 (Vela X-1) during inferior conjunction of the X-ray source. We detected pulsations at the 283.33 s X-ray pulse period in the absorption lines Si IV λ1402 and N V λλ1238, 1242. The pulse amplitudes in the UV lines were ∼3%. The profile of the pulsed UV intensity in the Si IV absorption line resembled that of the soft X-rays, while that in the N V line was anticorrelated with the profile of the hard X-ray pulsations. The effect is probably due to photoionization of Si IV and N IV in the stellar wind of HD 77581 by the rotating beam of Vela X-1. Publication: The Astrophysical Journal Pub Date: July 1996 DOI: 10.1086/177477 Bibcode: 1996ApJ...465..940B Keywords: STARS: INDIVIDUAL CONSTELLATION NAME: VELA X-1; STARS: OSCILLATIONS; X-RAYS: STARS full text sources ADS | data products SIMBAD (4) MAST (1) ESA (1)