Hysteresis in the spectral states of the neutron star low-mass X-ray binary EXO 1745-248

Дата и время публикации : 2011-01-27T18:21:11Z

Авторы публикации и институты :
Arunava Mukherjee (TIFR, India)
Sudip Bhattacharyya (TIFR, India)

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: 8 pages, 4 figures, 1 table, submitted to MNRAS
Первичная категория: astro-ph.HE

Все категории : astro-ph.HE, astro-ph.GA

Краткий обзор статьи: We study the low-frequency timing properties and the spectral state evolution of the transient neutron star low-mass X-ray binary EXO 1745-248 using the entire Rossi X-ray Timing Explorer Proportional Counter Array data. We tentatively conclude that EXO 1745-248 is an atoll source, and report the discovery of a ~ 0.45 Hz low-frequency quasi-periodic oscillation and ~ 10 Hz peaked noises. If it is an atoll, this source is unusual because (1) instead of a `C’-like curve, it traced a clear overall clockwise hysteresis curve in each of the colour-colour diagram and the hardness-intensity diagram; and (2) the source took at least 2.5 months to trace the softer banana state, as opposed to a few hours to a day, which is typical for an atoll source. The shape of the hysteresis track was intermediate between the characteristic `q’-like curves of several black hole systems and `C’-like curves of atolls, implying that EXO 1745-248 is an important source for the unification of the black hole and neutron star accretion processes.

Category: Physics