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A timing analysis of VHE gamma-ray observations of Cen X-3 taken with the University of Durham Mark 6 telescope was performed, using both Rayleigh and Bayesian statistics. Data from only 1 observation produced evidence for periodicity, in a…

We present new X-ray observations of the high mass X-ray binary (HMXRB) pulsar OAO 1657-415, obtained during one orbital period (10.44 days) with the Rossi X-Ray Timing Explorer (RXTE). Using the binary orbital parameters, obtained from…

Astrophysics · Physics 2009-10-31 Altan Baykal

We report on long-term monitoring of the anomalous X-ray pulsar 1E 1048.1-5937 using the Rossi X-ray Timing Explorer. This pulsar's timing behavior is different from that of other AXPs. In particular, the pulsar shows significant deviations…

Astrophysics · Physics 2009-11-06 V. M. Kaspi , F. P. Gavriil , D. Chakrabarty , J. R. Lackey , M. P. Muno

In the period between May 1997 and August 1997 a series of pointed RXTE observations were made of Cyg X-3. During this period Cyg X-3 made a transition from a quiescent radio state to a flare state (including a major flare) and then…

We present the results of a detailed analysis of RXTE observations which show an unusual state transition between high-soft and low-soft states in the microquasar GRS 1915+105. The RXTE pointed observations reveal that these events appeared…

Astrophysics · Physics 2007-05-23 S. Naik , A. R. Rao , Sandip K. Chakrabarti

We present results of a comprehensive analysis of the X-ray pulsar X Persei over the period 1996 to 2011, encompassing the quite low state and subsequent strong outburst activity. Using data from the RXTE and Swift observatories we detected…

High Energy Astrophysical Phenomena · Physics 2015-06-04 A. Lutovinov , S. Tsygankov , M. Chernyakova

We have investigated the Quasi Periodic Oscillation (QPO) properties of the transient accreting X-ray pulsar XTE J1858+034 during the second outburst of this source in April-May 2004. We have used observations made with the Proportional…

Astrophysics · Physics 2009-11-11 U. Mukherjee , S. Bapna , H. Raichur , B. Paul , S. N. A. Jaaffrey

We study the spin-down changes of PSR B1859$+$07 over a period of more than 28 years of radio observation. We identify that the time derivative of the rotational frequency ($\nu$) varies quasi-periodically with a period of $\sim$350 days,…

Solar and Stellar Astrophysics · Physics 2015-11-18 B. B. P. Perera , B. W. Stappers , P. Weltevrede , A. G. Lyne , J. M. Rankin

We report on the serendipitous discovery of a new X-ray source, SAX J1802.7-2017, ~22' away from the bright X-ray source GX 9+1, during a BeppoSAX observation of the latter source on 2001 September 16-20. SAX J1802.7-2017 remained…

Astrophysics · Physics 2009-11-10 G. Augello , R. Iaria , N. R. Robba , T. Di Salvo , L. Burderi , G. Lavagetto , L. Stella

We have searched for persistent radio pulsations, bright single pulses, and bursts from four Southern anomalous X-ray pulsars (AXPs). Deep observations were conducted at 1.4 GHz in 1999 July and August with the Parkes 64-m telescope. For…

Astrophysics · Physics 2008-11-26 Fronefield Crawford , Jason W. T. Hessels , Victoria M. Kaspi

The wind-accreting X-ray binary pulsar and cyclotron line source Vela X-1 has been observed extensively during INTEGRAL Core Program observations of the Vela region in June-July and November-December 2003. In the latter set of observations…

We report detailed timing and spectral analysis of RXTE-PCA data obtained from observations during the outburst of a transient X-ray pulsar 1A 1118--61 in January 2009. The pulse profile showed significant evolution during the outburst and…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Jincy Devasia , Marykutty James , Biswajit Paul , Kavila Indulekha

We have compared simultaneous Ryle Telescope radio and Rossi X-Ray Timing Explorer X-ray observations of the galactic microquasar GRS 1915+105, using the classification of the X-ray behaviour in terms of three states as previously…

We present a study of the correlated spectral and timing behavior of the new X-ray transient SAX J1711.6-3808 during its 2001 outburst using data obtained with the RXTE. We also investigate the correlations between those source properties…

Astrophysics · Physics 2009-11-06 Rudy Wijnands , Jon M. Miller

Her X-1 has been monitored nearly continuously in soft X-rays (2-12 keV) since February 1996 by the ASM on board RXTE. We present analysis of these observations which include 23 contiguous 35-day cycles. We present the best yet average…

Astrophysics · Physics 2007-05-23 D. Matthew Scott Denis A. Leahy

We present a detailed analysis of observations of the high mass X-ray binary Cen X-3 spanning two consecutive binary orbits performed with the RXTE satellite in early March 1997. The PCA and HEXTE light curves both show a clear reduction in…

(Abridged) We present high-resolution Chandra X-ray observations of PSR B0833-45, the 89 ms pulsar associated with the Vela supernova remnant. We have acquired two observations separated by one month to search for changes in the pulsar and…

Astrophysics · Physics 2009-10-31 D. J. Helfand , E. V. Gotthelf , J. P. Halpern

With ASCA, we have detected three X-ray flares from the Class I protostar YLW15. The flares occurred every ~20 hours and showed an exponential decay with time constant 30-60 ks. The X-ray spectra are explained by a thin thermal plasma…

Astrophysics · Physics 2009-10-31 Yohko Tsuboi , Kensuke Imanishi , Katsuji Koyama , Nicolas Grosso , Thierry Montmerle

We report on Imaging X-ray polarimetry explorer (IXPE) observations of the Be-transient X-ray pulsar LS V +44 17/RX J0440.9+4431 made at two luminosity levels during the giant outburst in January--February 2023. Considering the observed…

High Energy Astrophysical Phenomena · Physics 2023-09-06 Victor Doroshenko , Juri Poutanen , Jeremy Heyl , Sergey S. Tsygankov , Ilaria Caiazzo , Roberto Turolla , Alexandra Veledina , Martin C. Weisskopf , Sofia V. Forsblom , Denis González-Caniulef , Vladislav Loktev , Christian Malacaria , Alexander A. Mushtukov , Valery F. Suleimanov , Alexander A. Lutovinov , Ilya A. Mereminskiy , Sergey V. Molkov , Alexander Salganik , Andrea Santangelo , Andrei V. Berdyugin , Vadim Kravtsov , Anagha P. Nitindala , Iván Agudo , Lucio A. Antonelli , Matteo Bachetti , Luca Baldini , Wayne H. Baumgartner , Ronaldo Bellazzini , Stefano Bianchi , Stephen D. Bongiorno , Raffaella Bonino , Alessandro Brez , Niccolò Bucciantini , Fiamma Capitanio , Simone Castellano , Elisabetta Cavazzuti , Chien-Ting Chen , Stefano Ciprini , Enrico Costa , Alessandra De Rosa , Ettore Del Monte , Laura Di Gesu , Niccolò Di Lalla , Alessandro Di Marco , Immacolata Donnarumma , Michal Dovčiak , Steven R. Ehlert , Teruaki Enoto , Yuri Evangelista , Sergio Fabiani , Riccardo Ferrazzoli , Javier A. García , Shuichi Gunji , Kiyoshi Hayashida , Wataru Iwakiri , Svetlana G. Jorstad , Philip Kaaret , Vladimir Karas , Fabian Kislat , Takao Kitaguchi , Jeffery J. Kolodziejczak , Henric Krawczynski , Fabio La Monaca , Luca Latronico , Ioannis Liodakis , Simone Maldera , Alberto Manfreda , Frédéric Marin , Andrea Marinucci , Alan P. Marscher , Herman L. Marshall , Francesco Massaro , Giorgio Matt , Ikuyuki Mitsuishi , Tsunefumi Mizuno , Fabio Muleri , Michela Negro , Chi-Yung Ng , Stephen L. O'Dell , Nicola Omodei , Chiara Oppedisano , Alessandro Papitto , George G. Pavlov , Abel L. Peirson , Matteo Perri , Melissa Pesce-Rollins , Pierre-Olivier Petrucci , Maura Pilia , Andrea Possenti , Simonetta Puccetti , Brian D. Ramsey , John Rankin , Ajay Ratheesh , Oliver J. Roberts , Roger W. Romani , Carmelo Sgrò , Patrick Slane , Paolo Soffitta , Gloria Spandre , Douglas A. Swartz , Toru Tamagawa , Fabrizio Tavecchio , Roberto Taverna , Yuzuru Tawara , Allyn F. Tennant , Nicholas E. Thomas , Francesco Tombesi , Alessio Trois , Jacco Vink , Kinwah Wu , Fei Xie , Silvia Zane

We investigate the radio emission behaviour of PSR B0823+26, a pulsar which is known to undergo pulse nulling, using an 153-d intensive sequence of observations. The pulsar is found to exhibit both short (~min) and unusually long-term…

High Energy Astrophysical Phenomena · Physics 2015-06-11 N. J. Young , B. W. Stappers , P. Weltevrede , A. G. Lyne , M. Kramer
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