S. E. Motta - University of Oxford - Department of Physics, Astrophysics, Oxford, UK

S. E. Motta
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S. E. Motta
University of Oxford - Department of Physics, Astrophysics, Oxford, UK
United Kingdom

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High Energy Astrophysical Phenomena (48)
Astrophysics of Galaxies (12)
Instrumentation and Methods for Astrophysics (3)
Cosmology and Nongalactic Astrophysics (2)

Publications Authored By S. E. Motta

Black hole X-ray transients show a variety of state transitions during their outburst phases, characterized by changes in their spectral and timing properties. In particular, power density spectra (PDS) show quasi periodic oscillations (QPOs) that can be related to the accretion regime of the source. We looked for type-C QPOs in the disc-dominated state (i. Read More

In June 2015, the black hole X-ray binary (BHXRB) V404 Cygni went into outburst for the first time since 1989. Here, we present a comprehensive search for quasi-periodic oscillations (QPOs) of V404 Cygni during its recent outburst, utilizing data from six instruments on board five different X-ray missions: Swift/XRT, Fermi/GBM, Chandra/ACIS, INTEGRAL's IBIS/ISGRI and JEM-X, and NuSTAR. We report the detection of a QPO at 18 mHz simultaneously with both Fermi/GBM and Swift/XRT, another example of a rare but slowly growing new class of mHz-QPOs in BHXRBs linked to sources with a high orbital inclination. Read More

After more than 26 years in quiescence, the black hole transient V404 Cyg went into a luminous outburst in June 2015, and additional activity was detected in late December of the same year. Here, we present an optical spectroscopic follow-up of the December mini-outburst, together with X-ray, optical and radio monitoring that spanned more than a month. Strong flares with gradually increasing intensity are detected in the three spectral ranges during the ~10 days following the Swift trigger. Read More

Quasi-periodic oscillations (QPOs) with frequencies from $\sim0.05$-$30$ Hz are a common feature in the X-ray emission of accreting black hole binaries. As the QPOs originate from the innermost accretion flow, they provide the opportunity to probe the behaviour of matter in extreme gravity. Read More

Aims. Hard X-ray spectra of black hole binaries (BHB) are produced by Comptonization of soft seed photons by hot electrons near the black hole. The slope of the resulting energy spectra is governed by two main parameters: the electron temperature and the optical depth of the emitting plasma. Read More

Authors: S. N. Zhang, M. Feroci, A. Santangelo, Y. W. Dong, H. Feng, F. J. Lu, K. Nandra, Z. S. Wang, S. Zhang, E. Bozzo, S. Brandt, A. De Rosa, L. J. Gou, M. Hernanz, M. van der Klis, X. D. Li, Y. Liu, P. Orleanski, G. Pareschi, M. Pohl, J. Poutanen, J. L. Qu, S. Schanne, L. Stella, P. Uttley, A. Watts, R. X. Xu, W. F. Yu, J. J. M. in 't Zand, S. Zane, L. Alvarez, L. Amati, L. Baldini, C. Bambi, S. Basso, S. Bhattacharyya, R. Bellazzini, T. Belloni, P. Bellutti, S. Bianchi, A. Brez, M. Bursa, V. Burwitz, C. Budtz-Jorgensen, I. Caiazzo, R. Campana, X. L. Cao, P. Casella, C. Y. Chen, L. Chen, T. X. Chen, Y. Chen, Y. Chen, Y. P. Chen, M. Civitani, F. Coti Zelati, W. Cui, W. W. Cui, Z. G. Dai, E. Del Monte, D. De Martino, S. Di Cosimo, S. Diebold, M. Dovciak, I. Donnarumma, V. Doroshenko, P. Esposito, Y. Evangelista, Y. Favre, P. Friedrich, F. Fuschino, J. L. Galvez, Z. L. Gao, M. Y. Ge, O. Gevin, D. Goetz, D. W. Han, J. Heyl, J. Horak, W. Hu, F. Huang, Q. S. Huang, R. Hudec, D. Huppenkothen, G. L. Israel, A. Ingram, V. Karas, D. Karelin, P. A. Jenke, L. Ji, T. Kennedy, S. Korpela, D. Kunneriath, C. Labanti, G. Li, X. Li, Z. S. Li, E. W. Liang, O. Limousin, L. Lin, Z. X. Ling, H. B. Liu, H. W. Liu, Z. Liu, B. Lu, N. Lund, D. Lai, B. Luo, T. Luo, B. Ma, S. Mahmoodifar, M. Marisaldi, A. Martindale, N. Meidinger, Y. P. Men, M. Michalska, R. Mignani, M. Minuti, S. Motta, F. Muleri, J. Neilsen, M. Orlandini, A T. Pan, A. Patruno, E. Perinati, A. Picciotto, C. Piemonte, M. Pinchera, A. Rachevski, M. Rapisarda, N. Rea, E. M. R. Rossi, A. Rubini, G. Sala, X. W. Shu, C. Sgro, Z. X. Shen, P. Soffitta, L. M. Song, G. Spandre, G. Stratta, T. E. Strohmayer, L. Sun, J. Svoboda, G. Tagliaferri, C. Tenzer, H. Tong, R. Taverna, G. Torok, R. Turolla, A. Vacchi, J. Wang, J. X. Wang, D. Walton, K. Wang, J. F. Wang, R. J. Wang, Y. F. Wang, S. S. Weng, J. Wilms, B. Winter, X. Wu, X. F. Wu, S. L. Xiong, Y. P. Xu, Y. Q. Xue, Z. Yan, S. Yang, X. Yang, Y. J. Yang, F. Yuan, W. M. Yuan, Y. F. Yuan, G. Zampa, N. Zampa, A. Zdziarski, C. Zhang, C. L. Zhang, L. Zhang, X. Zhang, Z. Zhang, W. D. Zhang, S. J. Zheng, P. Zhou, X. L. Zhou

eXTP is a science mission designed to study the state of matter under extreme conditions of density, gravity and magnetism. Primary targets include isolated and binary neutron stars, strong magnetic field systems like magnetars, and stellar-mass and supermassive black holes. The mission carries a unique and unprecedented suite of state-of-the-art scientific instruments enabling for the first time ever the simultaneous spectral-timing-polarimetry studies of cosmic sources in the energy range from 0. Read More

Typical black hole binaries in outburst show spectral states and transitions, characterized by a clear connection between the inflow onto the black hole and outflow from its vicinity. The transient stellar mass black hole binary V404 Cyg apparently does not fit in this picture. Its outbursts are characterized by intense flares and intermittent low-flux states, with a dynamical range of several orders of magnitude on timescales of hours. Read More

Affiliations: 1-INAF-IASF Milano, 2-INAF-IASF Milano, 3-Department of Physics, Astrophysics, University of Oxford, 4-INAF, Osservatorio Astronomico di Roma, 5-INAF, Osservatorio Astronomico di Roma

We report on the discovery of mHz quasi-periodic oscillations (QPOs) from the high mass X-ray binary (HMXB) IGRJ19140+0951, during a 40 ks XMM-Newton observation performed in 201 5, which caught the source in its faintest state ever observed. At the start of the observation, IGRJ19140+0951 was at a low flux of 2$\times$10$^{-12}$~erg~cm$^{-2}$~s$^{-1}$ ( 2-10 keV; L$_{\rm X}$=3$\times$10$^{33}$~erg~s$^{-1}$ at 3.6 kpc), then its emission rised reaching a flux 10 times higher, in a flare-like activity. Read More

The last two decades have seen a great improvement in our understand- ing of the complex phenomenology observed in transient black-hole binary systems, especially thanks to the activity of the Rossi X-Ray Timing Explorer satellite, com- plemented by observations from many other X-ray observatories and ground-based radio, optical and infrared facilities. Accretion alone cannot describe accurately the intricate behavior associated with black-hole transients and it is now clear that the role played by different kinds of (often massive) outflows seen at different phases of the outburst evolution of these systems is as fundamental as the one played by the accretion process itself. The spectral-timing states originally identified in the X-rays and fundamentally based on the observed effect of accretion, have acquired new importance as they now allow to describe within a coherent picture the phenomenology observed at other wave- length, where the effects of ejection processes are most evident. Read More

Fast time variability is the most prominent characteristic of accreting systems and the presence of quasi periodic oscillations (QPOs) is a constant in all accreting systems, from cataclysmic variables to AGNs, passing through black hole and neutron star X-ray binaries and through the enigmatic ultra-luminous X-ray sources. In this paper I will briefly review the current knowledge of QPOs in black hole X-ray binaries, mainly focussing on their observed properties, but also mentioning the most important models that have been proposed to explain the origin of QPOs over the last decades. Read More

In this paper, we report on the available X-ray data collected by INTEGRAL, Swift, and XMM-Newton during the first outburst of the INTEGRAL transient IGR J17451-3022, discovered in 2014 August. The monitoring observations provided by the JEM-X instruments on-board INTEGRAL and the Swift/XRT showed that the event lasted for about 9 months and that the emission of the source remained soft for the entire period. The source emission is dominated by a thermal component (kT~1. Read More

Affiliations: 1INAF-Osservatorio Astronomico di Cagliari, Selargius, 2INAF-Osservatorio Astronomico di Cagliari, Selargius, 3INAF-Osservatorio Astronomico di Cagliari, Selargius, 4INAF-Osservatorio Astronomico di Cagliari, Selargius, 5Jodrell Bank Centre for Astrophysics, Manchester, UK, 6Department of Physics, Purdue University, West Lafayette, IN, USA, 7Jodrell Bank Centre for Astrophysics, Manchester, UK, 8INAF-Osservatorio Astronomico di Cagliari, Selargius, 9University of Oxford - Department of Physics, Astrophysics, Oxford, UK, 10INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, Milano, Italy, 11INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, Milano, Italy

The relativistic double neutron star binary PSR J0737-3039 shows clear evidence of orbital phase-dependent wind-companion interaction, both in radio and X-rays. In this paper we present the results of timing analysis of PSR J0737-3039 performed during 2006 and 2011 XMM-Newton Large Programs that collected ~20,000 X-ray counts from the system. We detected pulsations from PSR J0737-3039A (PSR A) through the most accurate timing measurement obtained by XMM-Newton so far, the spin period error being of 2x10^-13 s. Read More

We studied time variability and spectral evolution of the Galactic black hole transient Swift J174510.8-262411 during the first phase of its outburst. INTEGRAL and Swift observations collected from 2012 September 16 until October 30 have been used. Read More

We study the timing and spectral properties of the low-magnetic field, transient magnetar SWIFT J1822.3-1606 as it approached quiescence. We coherently phase-connect the observations over a time-span of ~500 days since the discovery of SWIFT J1822. Read More

We present unpublished data from a tidal disruption candidate in NGC 3599 which show that the galaxy was already X-ray bright 18 months before the measurement which led to its classification. This removes the possibility that the flare was caused by a classical, fast-rising, short-peaked, tidal disruption event. Recent relativistic simulations indicate that the majority of disruptions will actually take months or years to rise to a peak, which will then be maintained for longer than previously thought. Read More

This is a White Paper in support of the mission concept of the Large Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We discuss the potential of LOFT for the study of the physics of accretion and ejection around compact objects. For a summary, we refer to the paper. Read More

We studied the properties of the low-frequency quasi-periodic oscillations detected in a sample of six black hole candidates (XTE J1550-564, H 1743-322, XTE J1859+226, 4U 1630-47,GX 339-4, XTE J1650-500) observed by the Rossi XTE satellite. We analyzed the relation between the full width half maximum and the frequency of all the narrow peaks detected in power density spectra where a type-C QPO is observed. Our goal was to understand the nature of the modulation of the signal by comparing the properties of different harmonic peaks in the power density spectrum. Read More

NGC 55 ULX1 is a bright Ultraluminous X-ray source located 1.78 Mpc away. We analysed a sample of 20 Swift observations, taken between 2013 April and August, and two Chandra observations taken in 2001 September and 2004 June. Read More

Authors: M. Feroci1, J. W. den Herder2, E. Bozzo3, D. Barret4, S. Brandt5, M. Hernanz6, M. van der Klis7, M. Pohl8, A. Santangelo9, L. Stella10, A. Watts11, J. Wilms12, S. Zane13, M. Ahangarianabhari14, C. Albertus15, M. Alford16, A. Alpar17, D. Altamirano18, L. Alvarez19, L. Amati20, C. Amoros21, N. Andersson22, A. Antonelli23, A. Argan24, R. Artigue25, B. Artigues26, J. -L. Atteia27, P. Azzarello28, P. Bakala29, G. Baldazzi30, S. Balman31, M. Barbera32, C. van Baren33, S. Bhattacharyya34, A. Baykal35, T. Belloni36, F. Bernardini37, G. Bertuccio38, S. Bianchi39, A. Bianchini40, P. Binko41, P. Blay42, F. Bocchino43, P. Bodin44, I. Bombaci45, J. -M. Bonnet Bidaud46, S. Boutloukos47, L. Bradley48, J. Braga49, E. Brown50, N. Bucciantini51, L. Burderi52, M. Burgay53, M. Bursa54, C. Budtz-Jørgensen55, E. Cackett56, F. R. Cadoux57, P. Cais58, G. A. Caliandro59, R. Campana60, S. Campana61, F. Capitanio62, J. Casares63, P. Casella64, A. J. Castro-Tirado65, E. Cavazzuti66, P. Cerda-Duran67, D. Chakrabarty68, F. Château69, J. Chenevez70, J. Coker71, R. Cole72, A. Collura73, R. Cornelisse74, T. Courvoisier75, A. Cros76, A. Cumming77, G. Cusumano78, A. D'Aì79, V. D'Elia80, E. Del Monte81, A. De Luca82, D. De Martino83, J. P. C. Dercksen84, M. De Pasquale85, A. De Rosa86, M. Del Santo87, S. Di Cosimo88, S. Diebold89, T. Di Salvo90, I. Donnarumma91, A. Drago92, M. Durant93, D. Emmanoulopoulos94, M. H. Erkut95, P. Esposito96, Y. Evangelista97, A. Fabian98, M. Falanga99, Y. Favre100, C. Feldman101, V. Ferrari102, C. Ferrigno103, M. Finger104, M. H. Finger105, G. W. Fraser106, M. Frericks107, F. Fuschino108, M. Gabler109, D. K. Galloway110, J. L. Galvez Sanchez111, E. Garcia-Berro112, B. Gendre113, S. Gezari114, A. B. Giles115, M. Gilfanov116, P. Giommi117, G. Giovannini118, M. Giroletti119, E. Gogus120, A. Goldwurm121, K. Goluchová122, D. Götz123, C. Gouiffes124, M. Grassi125, P. Groot126, M. Gschwender127, L. Gualtieri128, C. Guidorzi129, L. Guy130, D. Haas131, P. Haensel132, M. Hailey133, F. Hansen134, D. H. Hartmann135, C. A. Haswell136, K. Hebeler137, A. Heger138, W. Hermsen139, J. Homan140, A. Hornstrup141, R. Hudec142, J. Huovelin143, A. Ingram144, J. J. M. in't Zand145, G. Israel146, K. Iwasawa147, L. Izzo148, H. M. Jacobs149, F. Jetter150, T. Johannsen151, H. M. Jacobs152, P. Jonker153, J. Josè154, P. Kaaret155, G. Kanbach156, V. Karas157, D. Karelin158, D. Kataria159, L. Keek160, T. Kennedy161, D. Klochkov162, W. Kluzniak163, K. Kokkotas164, S. Korpela165, C. Kouveliotou166, I. Kreykenbohm167, L. M. Kuiper168, I. Kuvvetli169, C. Labanti170, D. Lai171, F. K. Lamb172, P. P. Laubert173, F. Lebrun174, D. Lin175, D. Linder176, G. Lodato177, F. Longo178, N. Lund179, T. J. Maccarone180, D. Macera181, S. Maestre182, S. Mahmoodifar183, D. Maier184, P. Malcovati185, I. Mandel186, V. Mangano187, A. Manousakis188, M. Marisaldi189, A. Markowitz190, A. Martindale191, G. Matt192, I. M. McHardy193, A. Melatos194, M. Mendez195, S. Mereghetti196, M. Michalska197, S. Migliari198, R. Mignani199, M. C. Miller200, J. M. Miller201, T. Mineo202, G. Miniutti203, S. Morsink204, C. Motch205, S. Motta206, M. Mouchet207, G. Mouret208, J. Mulačová209, F. Muleri210, T. Muñoz-Darias211, I. Negueruela212, J. Neilsen213, A. J. Norton214, M. Nowak215, P. O'Brien216, P. E. H. Olsen217, M. Orienti218, M. Orio219, M. Orlandini220, P. Orleanski221, J. P. Osborne222, R. Osten223, F. Ozel224, L. Pacciani225, M. Paolillo226, A. Papitto227, J. M. Paredes228, A. Patruno229, B. Paul230, E. Perinati231, A. Pellizzoni232, A. V. Penacchioni233, M. A. Perez234, V. Petracek235, C. Pittori236, J. Pons237, J. Portell238, A. Possenti239, J. Poutanen240, M. Prakash241, P. Le Provost242, D. Psaltis243, D. Rambaud244, P. Ramon245, G. Ramsay246, M. Rapisarda247, A. Rachevski248, I. Rashevskaya249, P. S. Ray250, N. Rea251, S. Reddy252, P. Reig253, M. Reina Aranda254, R. Remillard255, C. Reynolds256, L. Rezzolla257, M. Ribo258, R. de la Rie259, A. Riggio260, A. Rios261, P. Rodríguez- Gil262, J. Rodriguez263, R. Rohlfs264, P. Romano265, E. M. R. Rossi266, A. Rozanska267, A. Rousseau268, F. Ryde269, L. Sabau-Graziati270, G. Sala271, R. Salvaterra272, A. Sanna273, J. Sandberg274, S. Scaringi275, S. Schanne276, J. Schee277, C. Schmid278, S. Shore279, R. Schneider280, A. Schwenk281, A. D. Schwope282, J. -Y. Seyler283, A. Shearer284, A. Smith285, D. M. Smith286, P. J. Smith287, V. Sochora288, P. Soffitta289, P. Soleri290, A. Spencer291, B. Stappers292, A. W. Steiner293, N. Stergioulas294, G. Stratta295, T. E. Strohmayer296, Z. Stuchlik297, S. Suchy298, V. Sulemainov299, T. Takahashi300, F. Tamburini301, T. Tauris302, C. Tenzer303, L. Tolos304, F. Tombesi305, J. Tomsick306, G. Torok307, J. M. Torrejon308, D. F. Torres309, A. Tramacere310, A. Trois311, R. Turolla312, S. Turriziani313, P. Uter314, P. Uttley315, A. Vacchi316, P. Varniere317, S. Vaughan318, S. Vercellone319, V. Vrba320, D. Walton321, S. Watanabe322, R. Wawrzaszek323, N. Webb324, N. Weinberg325, H. Wende326, P. Wheatley327, R. Wijers328, R. Wijnands329, M. Wille330, C. A. Wilson-Hodge331, B. Winter332, K. Wood333, G. Zampa334, N. Zampa335, L. Zampieri336, L. Zdunik337, A. Zdziarski338, B. Zhang339, F. Zwart340, M. Ayre341, T. Boenke342, C. Corral van Damme343, E. Kuulkers344, D. Lumb345
Affiliations: 11,1b, 2SRON, The Netherlands, 3ISDC, Geneve University, Switzerland, 4IRAP, Toulouse, France, 5National Space Institute, Lyngby, Denmark, 6IEEC-CSIC-UPC-UB, Barcelona, Spain, 7Astronomical Institute Anton Pannekoek, University of Amsterdam, The Netherlands, 8DPNC, Geneve University, Switzerland, 9IAAT Tuebingen, Germany, 10INAF-OA Rome, Italy, 11Astronomical Institute Anton Pannekoek, University of Amsterdam, The Netherlands, 12University of Erlangen-Nuremberg, Germany, 13MSSL, Surrey, United Kingdom, 14Politecnico Milano, Italy, 15Universidad de Granada, Spain, 16Washington University, United States, 17Sabanci University, Istanbul, Turkey, 18Astronomical Institute Anton Pannekoek, University of Amsterdam, The Netherlands, 19IEEC-CSIC-UPC-UB, Barcelona, Spain, 20INAF-IASF-Bologna, Italy, 21IRAP, Toulouse, France, 22Faculty of Physical and Applied Sciences, University of Southampton, United Kingdom, 23ASDC, Rome, Italy, 24IAPS-INAF, Rome, Italy, 25IRAP, Toulouse, France, 26IEEC-CSIC-UPC-UB, Barcelona, Spain, 27IRAP, Toulouse, France, 28ISDC, Geneve University, Switzerland, 29Silesian University in Opava, Czech Republic, 30University of Bologna, Italy, 31Middle East Technical University, Ankara, Turkey, 32Dipartimento di Chimica e Fisica, Palermo University, Italy, 33SRON, The Netherlands, 34Tata Institute of Fundamental Research, Mumbai, India, 35Middle East Technical University, Ankara, Turkey, 36INAF-OA Brera, Italy, 37Wayne State University, Detroit, United States, 38Politecnico Milano, Italy, 39University of Rome III, Italy, 40Dept. of Physics and Astronomy University of Padua, Italy, 41ISDC, Geneve University, Switzerland, 42University of Valencia, Spain, 43INAF-OA Padova, Padova, Italy, 44CNES, Toulouse, France, 45University of Pisa, Italy, 46CEA Saclay, DSM/IRFU/SAp, France, 47IAAT Tuebingen, Germany, 48MSSL, Surrey, United Kingdom, 49INPE, São José dos Campos, Brazil, 50Michigan state University, United States, 51Arcetri Observatory, INAF, Firenze, Italy, 52Cagliari University, Italy, 53INAF-OA Cagliari, Italy, 54Astronomical Institute of the Academy of Sciences of the Czech Republic, Czech Republic, 55National Space Institute, Lyngby, Denmark, 56Wayne State University, Detroit, United States, 57DPNC, Geneve University, Switzerland, 58Laboratoire d'Astrophysique de Bordeaux, France, 59IEEC-CSIC-UPC-UB, Barcelona, Spain, 601,1b, 61INAF-OA Brera, Italy, 62IAPS-INAF, Rome, Italy, 63Instituto de Astrofisica de Canarias, Tenerife, Spain, 64INAF-OA Rome, Italy, 65Instituto Astrofisica de Andalucia, Granada, Spain, 66ASDC, Rome, Italy, 67University of Valencia, Spain, 68MIT, Cambridge, United States, 69CEA Saclay, DSM/IRFU/SAp, France, 70National Space Institute, Lyngby, Denmark, 71MSSL, Surrey, United Kingdom, 72MSSL, Surrey, United Kingdom, 73INAF- Osservatorio Astronomico di Palermo, Italy, 74Instituto de Astrofisica de Canarias, Tenerife, Spain, 75ISDC, Geneve University, Switzerland, 76IRAP, Toulouse, France, 77INAF-OA Capodimonte, Napoli, Italy, 78INAF IFC, Palermo, Italy, 79Dipartimento di Chimica e Fisica, Palermo University, Italy, 80ASDC, Rome, Italy, 811,1b, 82INAF-IASF-Milano, Italy, 83INAF-OA Capodimonte, Napoli, Italy, 84SRON, The Netherlands, 85MSSL, Surrey, United Kingdom, 86IAPS-INAF, Rome, Italy, 87IAPS-INAF, Rome, Italy, 88IAPS-INAF, Rome, Italy, 89IAAT Tuebingen, Germany, 90Dipartimento di Chimica e Fisica, Palermo University, Italy, 91IAPS-INAF, Rome, Italy, 92Ferrara University, Ferrara, Italy, 93Department of Medical Biophysics, University of Toronto, Canada, 94School of Physics and Astronomy, University of Southampton, United Kingdom, 95Istanbul Kültür University, Turkey, 96INAF-IASF-Milano, Italy, 971,1b, 98Cambridge University, Cambridge, United Kingdom, 99ISSI Bern, Switzerland, 100DPNC, Geneve University, Switzerland, 101Leicester University, United Kingdom, 102Sapienza University, Rome, Italy, 103ISDC, Geneve University, Switzerland, 104Charles University in Prague, Czech Republic, 105Universities Space Research Association, Huntsville, United States, 106Leicester University, United Kingdom, 107SRON, The Netherlands, 108INAF-IASF-Bologna, Italy, 109University of Valencia, Spain, 110Monash Centre for Astrophysics, School of Physics and School of Mathematical Sciences, Monash University, Australia, 111IEEC-CSIC-UPC-UB, Barcelona, Spain, 112IEEC-CSIC-UPC-UB, Barcelona, Spain, 113ASDC, Rome, Italy, 114University of Maryland, United States, 115University of Tasmania, Australia, 116MPA Garching, Germany, 117ASDC, Rome, Italy, 118INAF-IRA-Bologna, Italy, 119INAF-IRA-Bologna, Italy, 120Sabanci University, Istanbul, Turkey, 121APC, Université Paris Diderot, CEA/Irfu, Observatoire de Paris, France, 122Silesian University in Opava, Czech Republic, 123CEA Saclay, DSM/IRFU/SAp, France, 124CEA Saclay, DSM/IRFU/SAp, France, 125Pavia University, Italy, 126Clemson University, United States, 127IAAT Tuebingen, Germany, 128Sapienza University, Rome, Italy, 129Ferrara University, Ferrara, Italy, 130ISDC, Geneve University, Switzerland, 131SRON, The Netherlands, 132Copernicus Astronomical Center, Warsaw, Poland, 133MSSL, Surrey, United Kingdom, 134National Space Institute, Lyngby, Denmark, 135Clemson University, United States, 136Open University, United Kingdom, 137Institut für Kernphysik, Technische Universität Darmstadt and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Germany, 138Monash Centre for Astrophysics, School of Physics and School of Mathematical Sciences, Monash University, Australia, 139SRON, The Netherlands, 140MIT, Cambridge, United States, 141National Space Institute, Lyngby, Denmark, 142Astronomical Institute of the Academy of Sciences of the Czech Republic, Czech Republic, 143University of Helsinki, Finland, 144Astronomical Institute Anton Pannekoek, University of Amsterdam, The Netherlands, 145SRON, The Netherlands, 146INAF-OA Rome, Italy, 147DAM and ICC-UB, Universitat de Barcelona, Spain, 148Sapienza University and ICRA, Rome, Italy, 149SRON, The Netherlands, 150IAAT Tuebingen, Germany, 151Perimeter Institute for Theoretical Physics, Waterloo, Canada, 152SRON, The Netherlands, 153SRON, The Netherlands, 154Technical University of Catalonia, Barcelona, Spain, 155Michigan state University, United States, 156Max-Planck-Institut fuer extraterrestrische Physik, Garching, Germany, 157Astronomical Institute of the Academy of Sciences of the Czech Republic, Czech Republic, 158IEEC-CSIC-UPC-UB, Barcelona, Spain, 159MSSL, Surrey, United Kingdom, 160Michigan state University, United States, 161MSSL, Surrey, United Kingdom, 162IAAT Tuebingen, Germany, 163Copernicus Astronomical Center, Warsaw, Poland, 164IAAT Tuebingen, Germany, 165University of Helsinki, Finland, 166NASA/Marshall Space Flight Center, United States, 167University of Erlangen-Nuremberg, Germany, 168SRON, The Netherlands, 169National Space Institute, Lyngby, Denmark, 170INAF-IASF-Bologna, Italy, 171Cornell University, Ithaca, United States, 172University of Illinois, United States, 173SRON, The Netherlands, 174APC, Université Paris Diderot, CEA/Irfu, Observatoire de Paris, France, 175IRAP, Toulouse, France, 176MSSL, Surrey, United Kingdom, 177Dipartimento di Fisica, Università degli Studi di Milano, Italy, 178University of Trieste, Italy, 179National Space Institute, Lyngby, Denmark, 180Texas Tech. University, United States, 181Politecnico Milano, Italy, 182IRAP, Toulouse, France, 183University of Maryland, United States, 184IAAT Tuebingen, Germany, 185Pavia University, Italy, 186School of Physics and Astronomy, University of Birmingham, United Kingdom, 187The Pennsylvania State University, United States, 188Copernicus Astronomical Center, Warsaw, Poland, 189INAF-IASF-Bologna, Italy, 190University of California, San Diego, United States, 191Leicester University, United Kingdom, 192University of Rome III, Italy, 193School of Physics and Astronomy, University of Southampton, United Kingdom, 194University of Melbourne, Australia, 195Kapteyn Astronomical Institute, University of Groningen, The Netherlands, 196INAF-IASF-Milano, Italy, 197Space Research Centre, Warsaw, Poland, 198DAM and ICC-UB, Universitat de Barcelona, Spain, 199INAF-IASF-Milano, Italy, 200University of Maryland, United States, 201Michigan state University, United States, 202INAF IFC, Palermo, Italy, 203Centro de Astrobiologia, 204University of Alberta, Canada, 205Observatoire Astronomique de Strasbourg, France, 206INAF-OA Brera, Italy, 207Université Paris Diderot France, 208IRAP, Toulouse, France, 209National Space Institute, Lyngby, Denmark, 2101,1b, 211Oxford University, United Kingdom, 212University of Alicante, Spain, 213MIT, Cambridge, United States, 214Open University, United Kingdom, 215MIT, Cambridge, United States, 216Leicester University, United Kingdom, 217National Space Institute, Lyngby, Denmark, 218INAF-IRA-Bologna, Italy, 219INAF-OA Padova, Padova, Italy, 220INAF-IASF-Bologna, Italy, 221Space Research Centre, Warsaw, Poland, 222Leicester University, United Kingdom, 223Space Telescope Institute, United States, 224University of Arizona, United States, 2251,1b, 226Università di Napoli Fedelico II, Italy, 227IEEC-CSIC-UPC-UB, Barcelona, Spain, 228DAM and ICC-UB, Universitat de Barcelona, Spain, 229Leiden Observatory, The Netherlands, 230Raman Research Institute, India, 231IAAT Tuebingen, Germany, 232INAF-OA Cagliari, Italy, 233Sapienza University and ICRA, Rome, Italy, 234Facultad de Ciencias-Trilingüe University of Salamanca, Spain, 235Czech Technical University in Prague, Czech Republic, 236ASDC, Rome, Italy, 237University of Alicante, Spain, 238IEEC-CSIC-UPC-UB, Barcelona, Spain, 239INAF-OA Cagliari, Italy, 240Tuorla Observatory, University of Turku, Finland, 241Ohio University, United States, 242CEA Saclay, DSM/IRFU/SAp, France, 243University of Arizona, United States, 244IRAP, Toulouse, France, 245IRAP, Toulouse, France, 246Armagh Observatory, United Kingdom, 2471,1b, 248INFN, Trieste, Italy, 249INFN, Trieste, Italy, 250NRL, Washington, United States, 251IEEC-CSIC-UPC-UB, Barcelona, Spain, 252Institute for Nuclear Theory, University of Washington, United States, 253Foundation for Research and Technology, Heraklion, Greece, 254National Institute of Aerospace Technology, 255MIT, Cambridge, United States, 256University of Maryland, United States, 257Max Planck Institute for Gravitational Physics, Germany, 258DAM and ICC-UB, Universitat de Barcelona, Spain, 259SRON, The Netherlands, 260INAF-OA Cagliari, Italy, 261University of Surrey, United Kingdom, 262Instituto de Astrofisica de Canarias, Tenerife, Spain, 263CEA Saclay, DSM/IRFU/SAp, France, 264ISDC, Geneve University, Switzerland, 265INAF IFC, Palermo, Italy, 266Leiden Observatory, The Netherlands, 267Copernicus Astronomical Center, Warsaw, Poland, 268MSSL, Surrey, United Kingdom, 269KTH Royal Institute of Technology, Stockholm, Sweden, 270National Institute of Aerospace Technology, 271IEEC-CSIC-UPC-UB, Barcelona, Spain, 272INAF-IASF-Milano, Italy, 273Kapteyn Astronomical Institute, University of Groningen, The Netherlands, 274Jorgen Sandberg Consulting, Denmark, 275Institute for Astronomy K.U. Leuven, Leuven, Belgium, 276CEA Saclay, DSM/IRFU/SAp, France, 277Silesian University in Opava, Czech Republic, 278University of Erlangen-Nuremberg, Germany, 279University of Pisa, Italy, 280INAF-OA Rome, Italy, 281Institut für Kernphysik, Technische Universität Darmstadt and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Germany, 282Leibniz-Institut fuer Astrophysik Potsdam, Germany, 283CNES, Toulouse, France, 284National University of Ireland, Ireland, 285MSSL, Surrey, United Kingdom, 286University of California, United States, 287MSSL, Surrey, United Kingdom, 288Astronomical Institute of the Academy of Sciences of the Czech Republic, Czech Republic, 289IAPS-INAF, Rome, Italy, 290Kapteyn Astronomical Institute, University of Groningen, The Netherlands, 291MSSL, Surrey, United Kingdom, 292University of Manchester, United Kingdom, 293Institute for Nuclear Theory, University of Washington, United States, 294Aristotle University of Thessaloniki, Greece, 295ASDC, Rome, Italy, 296Goddard Space Flight Center, Greenbelt, United States, 297Silesian University in Opava, Czech Republic, 298IAAT Tuebingen, Germany, 299IAAT Tuebingen, Germany, 300ISAS, Kanagawa, Japan, 301Dept. of Physics and Astronomy University of Padua, Italy, 302Argelander-Institut für Astronomie, Bonn, Germany, 303IAAT Tuebingen, Germany, 304IEEC-CSIC-UPC-UB, Barcelona, Spain, 305University of Maryland, United States, 306University of California, Berkeley, Space Sciences Laboratory, United States, 307Silesian University in Opava, Czech Republic, 308University of Alicante, Spain, 309ICREA, Barcelona, Spain, 310ISDC, Geneve University, Switzerland, 311IAPS-INAF, Rome, Italy, 312Dept. of Physics and Astronomy University of Padua, Italy, 313University of Rome Tor Vergata, Italy, 314IAAT Tuebingen, Germany, 315Astronomical Institute Anton Pannekoek, University of Amsterdam, The Netherlands, 316INFN, Trieste, Italy, 317APC, Université Paris Diderot, CEA/Irfu, Observatoire de Paris, France, 318Leicester University, United Kingdom, 319INAF IFC, Palermo, Italy, 320Physical Institute of the Academy of Sciences of the Czech Republic, Czech Republic, 321MSSL, Surrey, United Kingdom, 322ISAS, Kanagawa, Japan, 323Space Research Centre, Warsaw, Poland, 324IRAP, Toulouse, France, 325MIT, Cambridge, United States, 326IAAT Tuebingen, Germany, 327University of Warwick, United Kingdom, 328Astronomical Institute Anton Pannekoek, University of Amsterdam, The Netherlands, 329Astronomical Institute Anton Pannekoek, University of Amsterdam, The Netherlands, 330University of Erlangen-Nuremberg, Germany, 331NASA/Marshall Space Flight Center, Huntsville, United States, 332MSSL, Surrey, United Kingdom, 333NRL, Washington, United States, 334INFN, Trieste, Italy, 335INFN, Trieste, Italy, 336INAF-OA Padova, Padova, Italy, 337Copernicus Astronomical Center, Warsaw, Poland, 338Copernicus Astronomical Center, Warsaw, Poland, 339University of Nevada, Las Vegas, United States, 340SRON, The Netherlands, 341European Space Agency, ESTEC, The Netherlands, 342European Space Agency, ESTEC, The Netherlands, 343European Space Agency, ESTEC, The Netherlands, 344European Space Astronomy Centre, Madrid, Spain, 345European Space Agency, ESTEC, The Netherlands

The Large Observatory For x-ray Timing (LOFT) was studied within ESA M3 Cosmic Vision framework and participated in the final down-selection for a launch slot in 2022-2024. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument, LOFT will study the behaviour of matter under extreme conditions, such as the strong gravitational field in the innermost regions of accretion flows close to black holes and neutron stars, and the supra-nuclear densities in the interior of neutron stars. The science payload is based on a Large Area Detector (LAD, 10 m 2 effective area, 2-30 keV, 240 eV spectral resolution, 1 deg collimated field of view) and a WideField Monitor (WFM, 2-50 keV, 4 steradian field of view, 1 arcmin source location accuracy, 300 eV spectral resolution). Read More

The relativistic precession model (RPM) can be used to obtain a precise measurement of the mass and spin of a black hole when the appropriate set of quasi periodic oscillations is detected in the power-density spectrum of an accreting black hole. However, in previous studies the solution of the RPM equations could be obtained only through numerical methods at a price of an intensive computational effort. Here we demonstrate that the RPM system of equations can be solved analytically, drastically reducing the computational load, now limited to the Monte-Carlo simulation necessary to estimate the uncertainties. Read More

We have systematically studied a large sample of the neutron star low mass X-ray binaries (LMXBs) monitored by the Rossi X-ray Timing Explorer (50 sources; 10000+ observations). We find that the hysteresis patterns between Compton dominated and thermal dominated states, typically observed in black hole LMXBs, are also common in neutron star systems. These patterns, which also sample intermediate states, are found when looking at the evolution of both X-ray colour and fast variability of ten systems accreting below ~ 30 % of the Eddington Luminosity. Read More

We present a systematic study of the orbital inclination effects on black-hole transients fast time-variability properties. We have considered all the black-hole binaries that have been densely monitored by the Rossi XTE satellite. We find that the amplitude of low-frequency quasi periodic oscillations (QPOs) depends on the orbital inclination. Read More

We present a systematic analysis of the complete set of observations of the black hole (BH) binary XTE J1550-564 obtained by the Rossi X-ray Timing Explorer. We study the fast time variability properties of the source and determine the spin of the black hole through the relativistic precession model. Similarly to what is observed in the BH binary GRO J1655-40, the frequencies of the QPOs and broad band noise components match the general relativistic frequencies of particle motion close to the compact object predicted by the relativistic precession model. Read More

We report on the discovery with Chandra of a strong modulation (~90% pulsed fraction) at ~6.4 h from the source CXOU J123030.3+413853 in the star-forming, low-metallicity spiral galaxy NGC 4490, which is interacting with the irregular companion NGC 4485. Read More

We present a systematic analysis of the fast time variability properties of the transient black hole binary GRO J1655-40, based on the complete set of RossiXTE observations. We demonstrate that the frequencies of the quasi-periodic oscillations and of the broad band noise components and their variations match accurately the strong field general relativistic frequencies of particle motion in the close vicinity of the innermost stable circular orbit, as predicted by the relativistic precession model. We obtain high precision measurements of the black hole mass (M = (5. Read More

Affiliations: 1INAF -- Osservatorio Astronomico di Padova, 2INAF -- Istituto di Astrofisica Spaziale e Fisica Cosmica - Milano, 3ESA/European Space Astronomy Centre, Villanueva de la Cañada, 4INAF -- Osservatorio Astronomico di Padova

We present a multi-wavelenght study of the recently discovered Ultraluminous X-ray transient XMMUJ004243.6+412519 (ULX2 hereafter) in M31, based on Swift data and the 1.8-m Copernico Telescope in Asiago (Italy). Read More

We present a 30-day monitoring campaign of the optical counterpart of the bright X-ray transient Swift J1745-26, starting only 19 minutes after the discovery of the source. We observe the system peaking at i' ~17.6 on day 6 (MJD 56192) to then decay at a rate of ~0. Read More

We present a study of correlations between spectral and timing parameters for a sample of black hole X-ray binary candidates. Data are taken from GX 339-4, H 1743-322, and XTE J1650-500, as the Rossi X-ray Timing Explorer (RXTE) observed complete outbursts of these sources. In our study we investigate outbursts that happened before the end of 2009 to make use of the high-energy coverage of the HEXTE detector and select observations that show a certain type of quasi-periodic oscillations (type-C QPOs). Read More

Affiliations: 1U. Groningen, 2U. Southampton, 3ESAC, 4INAF-OAB, 5INAF-OAR, 6U. Groningen, 7U. Amsterdam, 8IAC, 9U. Amsterdam, 10U. Southampton, 11U. Amsterdam

We present our monitoring campaign of the outburst of the black-hole candidate Swift J1753.5-0127, observed with the Rossi X-ray Timing Explorer and the Swift satellites. After ~4. Read More

We use data of the bright atoll source 4U 1705-44 taken with XMM-Newton, BeppoSAX and RXTE both in the hard and in the soft state to perform a self-consistent study of the reflection component in this source. Although the data from these X-ray observatories are not simultaneous, the spectral decomposition is shown to be consistent among the different observations, when the source flux is similar. We therefore select observations performed at similar flux levels in the hard and soft state in order to study the spectral shape in these two states in a broad band (0. Read More

We report on a multi-wavelength study of the recently discovered X-ray transient XMMU J004243.6+412519 in M31, based on data collected with Swift and the 1.8-m Copernico Telescope at Cima Ekar in Asiago (Italy) between 2012 February and August. Read More

Ultra-Luminous X-ray sources are accreting black holes that might represent strong evidence of the Intermediate Mass Black Holes (IMBH), proposed to exist by theoretical studies but with no firm detection (as a class) so far. We analyze the best X-ray timing and spectral data from the ULX in NGC 5408 provided by XMM-Newton. The main goal is to study the broad-band noise variability of the source. Read More

Authors: M. Feroci, J. W. den Herder, E. Bozzo, D. Barret, S. Brandt, M. Hernanz, M. van der Klis, M. Pohl, A. Santangelo, L. Stella, A. Watts, J. Wilms, S. Zane, M. Ahangarianabhari, A. Alpar, D. Altamirano, L. Alvarez, L. Amati, C. Amoros, N. Andersson, A. Antonelli, A. Argan, R. Artigue, P. Azzarello, G. Baldazzi, S. Balman, M. Barbera, T. Belloni, G. Bertuccio, S. Bianchi, A. Bianchini, P. Bodin, J. -M. Bonnet Bidaud, S. Boutloukos, J. Braga, E. Brown, N. Bucciantini, L. Burderi, M. Bursa, C. Budtz-Jørgensen, E. Cackett, F. R. Cadoux, P. Cais, G. A. Caliandro, R. Campana, S. Campana, P. Casella, D. Chakrabarty, J. Chenevez, J. Coker, R. Cole, A. Collura, T. Courvoisier, A. Cros, A. Cumming, G. Cusumano, A. D'Aì, V. D'Elia, E. Del Monte, D. De Martino, A. De Rosa, S. Di Cosimo, S. Diebold, T. Di Salvo, I. Donnarumma, A. Drago, M. Durant, D. Emmanoulopoulos, Y. Evangelista, A. Fabian, M. Falanga, Y. Favre, C. Feldman, C. Ferrigno, M. H. Finger, G. W. Fraser, F. Fuschino, D. K. Galloway, J. L. Galvez Sanchez, E. Garcia-Berro, B. Gendre, S. Gezari, A. B. Giles, M. Gilfanov, P. Giommi, G. Giovannini, M. Giroletti, A. Goldwurm, D. Götz, C. Gouiffes, M. Grassi, P. Groot C. Guidorzi, D. Haas, F. Hansen, D. H. Hartmann, C. A. Haswe, A. Heger, J. Homan, A. Hornstrup, R. Hudec, J. Huovelin, A. Ingram, J. J. M. in't Zand, J. Isern, G. Israe, L. Izzo, P. Jonker, P. Kaaret, V. Karas, D. Karelin, D. Kataria, L. Keek, T. Kennedy, D. Klochkov, W. Kluzniak, K. Kokkotas, S. Korpela, C. Kouveliotou, I. Kreykenbohm, L. M. Kuiper, I. Kuvvetli, C. Labanti, D. Lai, F. K. Lamb, F. Lebrun, D. Lin, D. Linder, G. Lodato, F. Longo, N. Lund, T. J. Maccarone, D. Macera, D. Maier, P. Malcovati, V. Mangano, A. Manousakis, M. Marisaldi, A. Markowitz, A. Martindale, G. Matt, I. M. McHardy, A. Melatos, M. Mendez, S. Migliari, R. Mignani, M. C. Miller, J. M. Miller, T. Mineo, G. Miniutti, S. Morsink, C. Motch, S. Motta, M. Mouchet, F. Muleri, A. J. Norton, M. Nowak, P. O'Brien, M. Orienti, M. Orio, M. Orlandini, P. Orleanski, J. P. Osborne, R. Osten, F. Ozel, L. Pacciani, A. Papitto, B. Paul, E. Perinati, V. Petracek, J. Portell, J. Poutanen, D. Psaltis, D. Rambaud, G. Ramsay, M. Rapisarda, A. Rachevski, P. S. Ray, N. Rea, S. Reddy, P. Reig, M. Reina Aranda, R. Remillard, C. Reynolds, P. Rodríguez-Gil, J. Rodriguez, P. Romano, E. M. R. Rossi, F. Ryde, L. Sabau-Graziati, G. Sala, R. Salvaterra, A. Sanna, S. Schanne, J. Schee, C. Schmid, A. Schwenk, A. D. Schwope, J. -Y. Seyler, A. Shearer, A. Smith, D. M. Smith, P. J. Smith, V. Sochora, P. Soffitta, P. Soleri, B. Stappers, B. Stelzer, N. Stergioulas, G. Stratta, T. E. Strohmayer, Z. Stuchlik, S. Suchy, V. Sulemainov, T. Takahashi, F. Tamburini, C. Tenzer, L. Tolos, G. Torok, J. M. Torrejon, D. F. Torres, A. Tramacere, A. Trois, S. Turriziani, P. Uter, P. Uttley, A. Vacchi, P. Varniere, S. Vaughan, S. Vercellone, V. Vrba, D. Walton, S. Watanabe, R. Wawrzaszek, N. Webb, N. Weinberg, H. Wende, P. Wheatley, R. Wijers, R. Wijnands, M. Wille, C. A. Wilson-Hodge, B. Winter, K. Wood, G. Zampa, N. Zampa, L. Zampieri, A. Zdziarski, B. Zhang

The LOFT mission concept is one of four candidates selected by ESA for the M3 launch opportunity as Medium Size missions of the Cosmic Vision programme. The launch window is currently planned for between 2022 and 2024. LOFT is designed to exploit the diagnostics of rapid X-ray flux and spectral variability that directly probe the motion of matter down to distances very close to black holes and neutron stars, as well as the physical state of ultra-dense matter. Read More

We studied the low-frequency quasi-periodic oscillations (LFQPOs) in the black hole GRO J1655-40 during the 2005 outburst, using data from the Rossi X-ray Timing Explorer. All LFQPOs could be identified as either type B or type C using previously proposed classification schemes. In the soft state of the outburst the type-C LFQPOs reached frequencies that are among the highest ever seen for LFQPOs in black holes. Read More

On 2010 October 13, the X-ray astronomical satellite Rossi XTE, during the observation of the newly discovered accretion powered X-ray pulsar IGR J17480--2446, detected a lunar occultation of the source. From knowledge of lunar topography and Earth, Moon, and spacecraft ephemeris at the epoch of the event, we determined the source position with an accuracy of 40 mas (1{\sigma} c.l. Read More

(abridged) We analyse the spectral and pulse properties of the 11 Hz transient accreting pulsar, IGR J17480-2446, in the globular cluster Terzan 5, considering all the available RXTE, Swift and INTEGRAL observations performed between October and November, 2010. By measuring the pulse phase evolution we conclude that the NS spun up at an average rate of =1.48(2)E-12 Hz/s, compatible with the accretion of the Keplerian angular momentum of matter at the inner disc boundary. Read More

GRS 1915+105 is a widely studied black hole binary, well known because of its extremely fast and complex variability. Flaring periods of high variability alternate with "stable" phases (the plateaux) when the flux is low, the spectra are hard and the timing properties of the source are similar to those of a number of black hole candidates in hard spectral state. In the plateaux the power density spectra are dominated by a low frequency quasi periodic oscillation (LFQPO) superposed onto a band limited noise continuum and accompanied by at least one harmonic. Read More

We report on a spectral-timing analysis of the black hole X-ray binary candidate MAXI J1543- 564 during its 2011 outburst. All 99 pointed observations of this outburst obtained with the Rossi X-ray Timing Explorer (RXTE) were included in our study. We computed the fundamental diagrams commonly used to study black hole transients, and fitted power density and energy spectra to study the spectral and timing parameters along the outburst. Read More

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. Read More

We present optical monitoring of the black hole candidate XTE J1752-223 during its 2009 - 2010 outburst and decay to quiescence. The optical light curve can be described by an exponential decay followed by a plateau, then a more rapid fade towards quiescence. The plateau appears to be due to an extra component of optical emission that brightens and then fades over ~ 40 days. Read More

Affiliations: 1INAF-OAB, Merate, Italy, 2INAF-OAB, Merate, Italy, 3Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain

Sixteen years of observations of black hole transients with the Rossi X-ray Timing Explorer, complemented by other X-ray observatories and ground-based optical/infrared/radio telescopes have given us a clear view of the complex phenomenology associated with their bright outbursts. This has led to the definition of a small number of spectral/timing states which are separated by marked transitions in observables. The association of these states and their transitions to changes in the radio emission from relativistic radio jets completes the picture and have led to the study of the connection between accretion and ejection. Read More

We present a study of the spectral properties during state transition of GX 339-4. Data are taken from the 2010 outburst of GX 339-4, which is densely covered by Rossi X-ray Timing Explorer, providing an excellent coverage of the state transitions between the low/hard state and the high/soft state. We select all observations within a certain hardness ratio range during the soft intermediate state (SIMS). Read More

We analyzed RXTE/PCA and HEXTE data of the transient black hole binary GX 339-4, col- lected over a time span of eight years. We studied the properties and the behavior of low frequency quasi periodic oscillations (QPOs) as a function of the integrated broad-band variability and the spectral parameters during four outbursts (2002, 2004, 2007, 2010). Most of the QPOs could be classified following the ABC classification that has been proposed before. Read More

We report on X-ray monitoring observations of the transient black hole candidate (BHC) XTE J1752-223 with the Rossi X-ray Timing Explorer (RXTE). The source was discovered on 2009 October 23 and during its low/hard state, which lasted for at least 25 days, all timing and spectral properties were similar to those of Cyg X-1 during its canonical hard state. The combined PCA/HEXTE spectra were well fitted by an absorbed broken powerlaw with a high energy cutoff. Read More

We present a comprehensive spectral-timing study of the black hole candidate MAXI J1659-152 during its 2010 outburst. We analysed 65 RXTE observations taken along this period and computed the fundamental diagrams commonly used to study black hole transients. We fitted power density and energy spectra and studied the evolution of the spectral and timing parameters along the outburst. Read More

The newly discovered 11 Hz accreting pulsar, IGR J17480-2446, located in the globular cluster Terzan 5, has shown several bursts with a recurrence time as short as few minutes. The source shows the shortest recurrence time ever observed from a neutron star. Here we present a study of the morphological, spectral and temporal properties of 107 of the bursts observed by the Rossi X-ray Timing Explorer. Read More

Affiliations: 1Univ.Cagliari, 2Univ.Palermo, 3INAF-OAB, 4INAF-OAC, 5Univ.Cagliari, 6Univ.Palermo, 7INAF-OAB, 8Univ.Palermo

We present an analysis of the spin and orbital properties of the newly discovered accreting pulsar IGR J17480-2446, located in the globular cluster Terzan 5. Considering the pulses detected by the Rossi X-ray Timing Explorer at a period of 90.539645(2) ms, we derive a solution for the 21. Read More

We present the rms-intensity diagram for black hole transients. Using observations taken with the Rossi X-ray timing explorer we study the relation between the root mean square (rms) amplitude of the variability and the net count-rate during the 2002, 2004 and 2007 outbursts of the black hole X-ray binary GX 339-4. We find that the rms-flux relation previously observed during the hard state in X-ray binaries does not hold for the other states, when different relations apply. Read More