1st PostDoc: Teo Muñoz-Darias & 2nd PostDoc: Holger Stiele

• outreach page of the project, by Teo Muñoz-Darias

Time for 1st PostDoc project: Feb 2009 -Jan 2011
Time for 2nd PostDoc project: April 2010-March 2012
Responsible Advisor: Tomaso Belloni (INAF Brera)
Co-Advisors: Michiel van der Klis (Amsterdam), Emrah Kalemci (Sabanci), Stéphane Corbel (CEA Saclay), Jörn Wilms (FAU Erlangen-Nuremberg)

Galactic back holes in binary systems can accrete matter from the companion star. Close to the compact object, the accreting plasma emits in the X-ray band and can reach very high luminosities. This region located a few kilometers from a black hole constitutes an ideal laboratory for studying the effects of General Relativity in presence of a strong field. At the same time, it is important to study the properties of the accretion flow itself. Its different physical components and emission mechanisms are very complex and not yet fully understood. Moreover, there is a strong relation between the accretion properties and the ejection of powerful relativistic jets from the systems. In particular, the observed X-ray flux varies in a non-periodic fashion on very fast time scales, down to a few milliseconds. This complex fast time variability shows a marked dependence on the energy spectrum of the source, with transitions which can be as fast as a few seconds. The spectral dependence of this variability also changes markedly as a function of the energy spectrum, leading to a rather complex picture. This postdoc project will seek an improved understanding of these issues through the analysis of archival and new RXTE, INTEGRAL and Swift data for both black hole and neutron star X-ray binaries. Power-density spectra, phase-lag spectra and rms-weighed energy spectra will be produced and the structure and evolution of the different components will be studied as a function of the system’s spectral properties. A homogeneous analysis with both black-hole and neutron-star binaries will allow a comparison of the observational properties and advance our understanding of the full relation between spectral components and fast time variability. In addition, we will perform an unbiased search for high-frequency oscillations in black-hole binaries, which constitute the best approach for obtaining observational evidence for strong gravity effects. These oscillations do not obviously correspond to any of the main features in the variability of NS binaries. The detections will be studied in terms of timing and spectral properties and will provide a firm observational ground for the interpretation in terms of relativistic models.
The project is led by Dr. Tomaso Belloni, who is a leading expert on aperiodic time variability from X-ray binaries and on the global properties of black-hole systems. It will be carried on in collaboration with other institutes of the network as listed above and includes trips to these institutions. Because of the complexity of the research to be undertaken, the project will be performed by two postdoctorial researchers, both employed for 24 months each, and starting in January 2009 and April 2010, respectively.

An overview talk on the current state  of the project as presented at the Collaboration Meeting in September 2010 in Istanbul can be found here.

Related publications

7. Durant, M., Shahbaz, T., Gandhi, P., Cornelisse, R., Muñoz-Darias, T., Casares, J., Dhillon, V., Marsh, T., Spruit, H., O'Brien, K., Steeghs, D., and Hynes, R., 2010, High time resolution optical/X-ray cross-correlations for X-ray binaries: anticorrelations and rapid variability, MNRAS, 1581 (ADS-Entry)
6. Muñoz-Darias, T., Motta, S., and Belloni, T. M., 2010, Fast variability as a tracer of accretion regimes in black hole transients, MNRAS, 1553 (ADS-Entry)
5. Rodríguez-Gil, P., Santander-García, M., Knigge, C., Corradi, R. L. M., Gänsicke, B. T., Barlow, M. J., Drake, J. J., Drew, J., Miszalski, B., Napiwotzki, R., Steeghs, D., Wesson, R., Zijlstra, A. A., Jones, D., Liimets, T., Muñoz-Darias, T., Pyrzas, S., and Rubio-Díez, M. M., 2010, The orbital period of V458 Vulpeculae, a post-double common-envelope nova, MNRAS, 407, 21 (ADS-Entry)
4. Motta, S., Muñoz-Darias, T., and Belloni, T. M., 2010, On the outburst evolution of H1743-322: a 2008/2009 comparison, MNRAS, 408, 1796 (ADS-Entry)
3. Göğüş, E., Cusumano, G., Levan, A. J., Kouveliotou, C., Sakamoto, T., Barthelmy, S. D., Campana, S., Kaneko, Y., Stappers, B. W., de Ugarte Postigo, A., Strohmayer, T., Palmer, D. M., Gelbord, J., Burrows, D. N., van der Horst, A. J., Muñoz-Darias, T., Gehrels, N., Hessels, J. W. T., Kamble, A. P., Wachter, S., Wiersema, K., Wijers, R. A. M. J., and Woods, P. M., 2010, Discovery of a New Soft Gamma Repeater, SGR J1833-0832, ApJ, 718, 331 (ADS-Entry)
2. Muñoz-Darias, T., Motta, S., Pawar, D., Belloni, T. M., Campana, S., and Bhattacharya, D., 2010, The hard state of black hole candidates: XTEJ1752-223, MNRAS, 404, 94 (ADS-Entry)
1. Dobrotka, A., Hric, L., Casares, J., Shahbaz, T., Martínez-Pais, I. G., and Muñoz-Darias, T., 2010, Searching for flickering statistics in T CrB, MNRAS, 402, 2567 (ADS-Entry)

1. Muñoz-Darias, T., 2010, Mapping LMXBs with reprocessed X-ray burst, in: High Time Resolution Astrophysics IV, held on May 5-7, Agios Nikolaos, Crete, Greece, in press (ADS-Entry)

11. Muñoz-Darias, T., Stiele, H., Belloni, T. M., and Motta, S., 2010, Soft-to-Hard transition in MAXI J1659-152, ATel 2999 (ATel-Link)
10. Belloni, T. M., Motta, S., and Muñoz-Darias, T., 2010, Transition to the soft-intermediate state of MAXI J1659-152, ATel 2927 (ATel-Link)
9. Belloni, T. M., Muñoz-Darias, T., and Kuulkers, E., 2010, RXTE dips yield better orbital period determination for MAXI J1659-152, ATel 2926 (ATel-Link)
8. Belloni, T. M., Muñoz-Darias, T., Motta, S., Stiele, H., and Carbone, D., 2010, State transition in H 1743-322, ATel 2797 (ATel-Link)
7. Belloni, T. M., Muñoz-Darias, T., Motta, S., Stiele, H., and Carbone, D., 2010, H 1743-322 approaching state transition, ATel 2792 (ATel-Link)
6. Belloni, T. M., Muñoz-Darias, T., Motta, S., Stiele, H., and Carbone, D., 2010, RXTE pointed observations of H 1743-322, ATel 2788 (ATel-Link)
5. Russell, D. M., Muñoz-Darias, T., Lewis, F., and Soleri, P., 2010, XTE J1752-223 has faded to quiescence: optical and infrared magnitudes, ATel 2775 (ATel-Link)
4. Motta, S., Belloni, T. M., Muñoz-Darias, T., and Homan, J., 2010, Multiple fast state transitions in GX 339-4, ATel 2593 (ATel-Link)
3. Belloni, T. M., Motta, S., and Muñoz-Darias, T., 2010, Transition to the soft state in GX 339-4, ATel 2577 (ATel-Link)
2. Motta, S., Belloni, T. M., and Muñoz-Darias, T., 2010, GX 339-4 in transition from the hard state, ATel 2545 (ATel-Link)
1. Muñoz-Darias, T., Motta, S., Belloni, T. M., and Homan, J., 2010, XTE J1752-223 in transition from a soft to a hard state, ATel 2518 (ATel-Link)