The faint 'heartbeats' of IGR J17091-3624: an exceptional black-hole candidate
| Autor: | Altamirano, D., Belloni, T., Linares, M., van der Klis, M., Wijnands, R., Curran, P. A., Kalamkar, M., Stiele, H., Motta, S., Munoz-Darias, T., Casella, P., Krimm, H. |
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| Rok vydání: | 2011 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1088/2041-8205/742/2/L17 |
| Popis: | We report on the first 180 days of RXTE observations of the outburst of the black hole candidate IGR J17091-3624. This source exhibits a broad variety of complex light curve patterns including periods of strong flares alternating with quiet intervals. Similar patterns in the X-ray light curves have been seen in the (up to now) unique black hole system GRS 1915+105. In the context of the variability classes defined by Belloni et al. (2000) for GRS 1915+105, we find that IGR J17091-3624 shows the \nu, \rho, \alpha, \lambda, \beta and \mu classes as well as quiet periods which resemble the \chi class, all occurring at 2-60 keV count rate levels which can be 10-50 times lower than observed in GRS 1915+105. The so-called \rho class "heartbeats" occur as fast as every few seconds and as slow as ~100 seconds, tracing a loop in the hardness-intensity diagram which resembles that previously seen in GRS 1915+105. However, while GRS 1915+105 traverses this loop clockwise, IGR J17091-3624 does so in the opposite sense. We briefly discuss our findings in the context of the models proposed for GRS 1915+105 and find that either all models requiring near Eddington luminosities for GRS 1915+105-like variability fail, or IGR J17091-3624 lies at a distance well in excess of 20 kpc or, it harbors one of the least massive black holes known (< 3 M_sun). Comment: 7 pages, 5 figures, published on ApJ Letters |
| Databáze: | arXiv |
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