Detection of a broad iron emission line and sub-millisecond quasiperiodic oscillations from the type I X-ray burster 4U1728-34 in a high state

2000/08/09 by S. Piraino, Piraino, S., A. Santangelo +3
Earth and Planetary Sciences · Engineering · Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #Gamma-ray bursts and supernovae #High-pressure geophysics and materials #Mechanics and Biomechanics Studies #Pulsars and Gravitational Waves Research #astro-ph

paper · pdf · doi:10.48550/arxiv.astro-ph/0008141

4 pages, to appear in Astronomy and Astrophysics Letters

arxiv created 2000/08/09 · openalex publication_date 2000/08/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We report results from simultaneous RossiXTE and BeppoSAX observations of the neutron-star x-ray binary and type I X-ray burster 4U1728-34. The source was found in a high luminosity state, L_X near 0.1 L_Edd, and quasiperiodic oscillations were detected at 1284 +/- 6 Hz, the highest frequency ever observed from this source. The x-ray spectrum shows a broad, FWHM = 0.8 keV, iron K-alpha fluorescence line. We discuss interpretations of the broad line and the quasiperiodic oscillations and how future simultaneous spectral and timing observations can be used to test these interpretations and, potentially, to estimate the mass of the compact object.

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