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Published version

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2005-11

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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/99489

The Island State of the Atoll Source 4U 1820-30

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http://dx.doi.org/10.1086/447761

Abstract

We study the rapid X-ray time variability in all public data available from the Rossi X-Ray Timing Explorer Proportional Counter Array on the atoll source 4U 1820-30 in the low-luminosity island state. A total of ~46 ks of data were used. We compare the frequencies of the variability components of 4U 1820-30 with those in other atoll sources. These frequencies were previously found to follow a universal scheme of correlations. We find that 4U 1820-30 shows correlations that are shifted by factors of 1.13 ± 0.01 and 1.21 ± 0.02 with respect to those in other atoll sources. These shifts are similar to, but smaller than, the shift factor of ~1.45 previously reported for some accreting millisecond pulsars. Therefore, 4U 1820-30 is the first atoll source that shows no significant pulsations but has a significant shift in the frequency correlations compared with the other three nonpulsating atoll sources.

Subject

Estels binaris de raigs X, Estels de neutrons, Astronomia de raigs X

Subject (English)

X-ray binaries, Neutron stars, X-ray astronomy

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Articles publicats en revistes (Física Quàntica i Astrofísica)

Citation

ALTAMIRANO, Diego, et al. The Island State of the Atoll Source 4U 1820-30. Astrophysical Journal. 2005. Vol. 633, num. 1, pags. 358-366. ISSN 0004-637X. [consulted: 12 of August of 2026]. Available at: https://hdl.handle.net/2445/99489

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