Near-infrared/optical identification of five low-luminosity X-ray pulsators (2009)
Kaur, Ramanpreet, Wijnands, Rudy, Paul, Biswajit, Patruno, Alessandro, Degenaar, Nathalie
We present the identification of the most likely near-infrared/optical counterparts of five low-luminosity X-ray pulsators (AX J1700.1-4157, AX 1740.1-2847, AX J1749.2-2725, AX J1820.5-1434 and AX...
Watts, Anna L., Altamirano, Diego, Linares, Manuel, Patruno, Alessandro, Casella, Piergiorgio, Cavecchi, Yuri, ...
We report the discovery of burst oscillations from the intermittent accretion-powered millisecond pulsar (AMP) HETE J1900.1-2455, with a frequency approximately 1 Hz below the known spin frequency....
Type I X-ray Bursts from the Neutron-star Transient XTE J1701-462 (2009)
Lin, Dacheng, Altamirano, Diego, Homan, Jeroen, Remillard, Ronald A., Wijnands, Rudy, Belloni, Tomaso
The neutron-star X-ray transient XTE J1701-462 was observed for $\sim$3 Ms with \xte during its 2006-2007 outburst. Here we report on the discovery of three type-I X-ray bursts from XTE J1701-462....
An alternative interpretation of the timing noise in accreting millisecond pulsars (2009)
Patruno, Alessandro, Wijnands, Rudy, Van Der Klis, Michiel
The measurement of the spin frequency in accreting millisecond X-ray pulsars (AMXPs) is strongly affected by the presence of an unmodeled component in the pulse arrival times called 'timing noise'....
Hiemstra, Beike, Soleri, Paolo, Mendez, Mariano, Belloni, Tomaso, Mostafa, Reham, Wijnands, Rudy
We analyzed simultaneous archival XMM-Newton and RXTE observations of the X-ray binary and black hole candidate Swift J1753.5-0127. In a previous analysis of the same data a soft thermal component...
A decade of accreting millisecond x-ray pulsars (2008)
Wijnands, Rudy, Altamirano, Diego, Soleri, Paolo, Degenaar, Nathalie, Rea, Nanda, Casella, Piergiorgio, ...
GCRT J1742-3001: A New Radio Transient Towards the Galactic Center (2008)
Hyman, Scott D., Wijnands, Rudy, Lazio, T. Joseph W., Pal, Sabyasachi, Starling, Rhaana, Kassim, Namir E., ...
We report the detection of a new transient radio source, GCRT J1742-3001, located ~1 degree from the Galactic center. The source was detected ten times from late 2006 to 2007 May in our 235 MHz...
Kaur, Ramanpreet, Wijnands, Rudy, Patruno, Alessandro, Testa, Vincenzo, Israel, GianLuca, Degenaar, Nathalie, ...
We present results from our Chandra and XMM-Newton observations of two low-luminosity X-ray pulsators SAX J1324.4-6200 and SAX J1452.8-5949 which have spin-periods of 172 s and 437 s respectively....
The Swift capture of a long X-ray burst from XTE J1701-407 (2008)
Linares, Manuel, Watts, Anna L., Wijnands, Rudy, Soleri, Paolo, Degenaar, Nathalie, Curran, Peter A., ...
XTE J1701-407 is a new transient X-ray source discovered on June 8th, 2008. More than one month later it showed a rare type of thermonuclear explosion: a long type I X-ray burst. We report herein the...
Cooling of the crust in the neutron star low-mass X-ray binary MXB 1659-29 (2008)
Cackett, Edward M., Wijnands, Rudy, Miller, Jon M., Brown, Edward F., Degenaar, Nathalie
In quasi-persistent neutron star transients, long outbursts cause the neutron star crust to be heated out of thermal equilibrium with the rest of the star. During quiescence, the crust then cools...
Multiwavelength observations of the black hole candidate Swift J1753.5-0127 (2008)
Soleri, Paolo, Altamirano, Diego, Fender, Rob, Casella, Piergiorgio, Tudose, Valeriu, Maitra, Dipankar, ...
We present preliminary results from the analysis of simultaneous multiwavelength observations of the black hole candidate Swift J1753.5-0127. The source is still continuing its outburst started in...
Timing and spectral properties of the accreting millisecond pulsar SWIFT J1756.9-2508 (2008)
Linares, Manuel, Wijnands, Rudy, Van Der Klis, Michiel, Krimm, Hans, Markwardt, Craig, Chakrabarty, Deepto
SWIFT J1756.9-2508 is one of the few accreting millisecond pulsars (AMPs) discovered to date. We report here the results of our analysis of its aperiodic X-ray variability, as measured with the Rossi...
Enigmatic sub-luminous accreting neutron stars in our Galaxy (2008)
During the last few years a class of enigmatic sub-luminous accreting neutron stars has been found in our Galaxy. They have peak X-ray luminosities (2-10 keV) of a few times 1E34 erg/s to a few times...
Phase-coherent timing of the accreting millisecond pulsar SAX J1748.9-2021 (2008)
Patruno, Alessandro, Altamirano, Diego, Hessels, Jason W. T., Casella, Piergiorgio, Wijnands, Rudy, Van Der Klis, Michiel
We present a phase-coherent timing analysis of the intermittent accreting millisecond pulsar SAX J1748.9-2021. A new timing solution for the pulsar spin period and the Keplerian binary orbital...
GRB060602B = Swift J1749.4-2807: an unusual transiently accreting neutron-star X-ray binary (2007)
Wijnands, Rudy, Rol, Evert, Cackett, Ed M., Starling, Rhaana L. C., Remillard, Ron A.
We present an analysis of the Swift BAT and XRT data of GRB060602B, which is most likely an accreting neutron star in a binary system and not a gamma-ray burst. Our analysis shows that the BAT burst...
Cackett, Edward M., Miller, Jon M., Bhattacharyya, Sudip, Grindlay, Jonathan E., Homan, Jeroen, Van Der Klis, Michiel, ...
Using Suzaku observations of three neutron star low-mass X-ray binaries (Ser X-1, 4U 1820-30 and GX 349+2) we have found broad, asymmetric, relativistic Fe K emission lines in all three objects....
Kong, Albert K. H., Miller, Jon M., Mendez, Mariano, Cottam, Jean, Lewin, Walter H. G., Paerels, Frederik, ...
During a 200 ks observation with the XMM-Newton Reflection Grating Spectrometer, we detected 16 type-I X-ray bursts from GS 1826-24. We combined the burst spectra in an attempt to measure the...
Hartman, Jacob M., Patruno, Alessandro, Chakrabarty, Deepto, Kaplan, David L., Markwardt, Craig B., Morgan, Edward H., ...
We present a 7 yr timing study of the 2.5 ms X-ray pulsar SAX J1808.4-3658, an X-ray transient with a recurrence time of ~2 yr, using data from the Rossi X-ray Timing Explorer covering 4 transient...
The LOFAR Transients Key Project (2006)
Fender, Rob, Braun, Robert, Stappers, Ben, Wijers, Ralph, Wise, Michael, Coenen, Thijs, ...
LOFAR, the Low Frequency Array, is a new radio telescope under construction in the Netherlands, designed to operate between 30 and 240 MHz. The Transients Key Project is one of the four Key Science...
Accreting millisecond pulsars: one on each hand (2006)
Linares, Manuel, Van Der Klis, Michiel, Wijnands, Rudy
We report on the X-ray aperiodic timing analysis of two accreting millisecond pulsars: XTE J1807-294 and IGR J00291+5934. On the one hand, we discovered in XTE J1807-294 seven pairs of simultaneous...
Homan, Jeroen, Van Der Klis, Michiel, Wijnands, Rudy, Belloni, Tomaso, Fender, Rob, Klein-Wolt, Marc, ...
(Abridged) We report on ten weeks of RXTE observations of the X-ray transient XTE J1701-462. Comparisons with other sources suggest it had all the characteristics of the neutron star Z sources (the...
An accreting millisecond pulsar with black hole-like X-ray variability: IGR J00291+5934 (2006)
Linares, Manuel, Van Der Klis, Michiel, Wijnands, Rudy
IGR J00291+5934 is one of the seven accreting millisecond pulsars (AMPs) discovered so far. We report on the aperiodic timing and color analysis of its X-ray flux, using all the RXTE observations of...
Cooling of the quasi-persistent neutron star X-ray transients KS 1731-260 and MXB 1659-29 (2006)
Cackett, Edward M., Wijnands, Rudy, Linares, Manuel, Miller, Jon M., Homan, Jeroen, Lewin, Walter
We present Chandra and XMM-Newton X-ray observations that monitor the neutron star cooling of the quasi-persistent neutron star X-ray transients KS 1731-260 and MXB 1659-29 for approximately 4 years...
The magnetic nature of disk accretion onto black holes (2006)
Miller, J. M., Raymond, J., Fabian, A. C., Steeghs, D., Homan, J., Reynolds, C. S., ...
Although disk accretion onto compact objects - white dwarfs, neutron stars, and black holes - is central to much of high energy astrophysics, the mechanisms which enable this process have remained...
XMM-Newton Discovery of the X-ray Transient XMMU J181227.8-181234 in the Galactic Plane (2006)
Cackett, Edward M., Wijnands, Rudy, Remillard, Ron
We report the discovery of an X-ray transient, observed in outburst with XMM-Newton on March 20, 2003, and with position 18h12m27.8s, -18 12 34 (J2000, approximate positional error 2"). No known...
XMM-Newton observations of the black hole X-ray transient XTE J1650-500 in quiescence (2005)
Homan, Jeroen, Wijnands, Rudy, Kong, Albert, Miller, Jon M., Rossi, Sabrina, Belloni, Tomaso, ...
We report the result of an XMM-Newton observation of the black-hole X-ray transient XTE J1650-500 in quiescence. The source was not detected and we set upper limits on the 0.5-10 keV luminosity of...
Recent X-ray observations have detected a class of very faint X-ray transients in the Galaxy which probably reveal a previously unrecognised type of accretion on to neutron stars or black holes. We...
Accretion-driven millisecond X-ray pulsars (2005)
I present an overview of our current observational knowledge of the six known accretion-driven millisecond X-ray pulsars. A prominent place in this review is given to SAX J1808.4-3658; it was the...
Relations Between Timing Features and Colors in Accreting Millisecond Pulsars (2004)
Van Straaten, Steve, Van Der Klis, Michiel, Wijnands, Rudy
We have studied the aperiodic X-ray timing and color behavior of the accreting millisecond pulsars SAX J1808.4-3658, XTE J1751-305, XTE J0929-314, and XTE J1814-338 using large data sets obtained...
Cackett, Edward M., Wijnands, Rudy, Heinke, Craig O., Edmonds, Peter D., Lewin, Walter H. G., Pooley, David, ...
The globular cluster NGC 6440 is known to harbor a bright neutron-star X-ray transient. We observed the globular cluster with Chandra on two occasions when the bright transient was in its quiescent...
Homan, Jeroen, Miller, Jon M., Wijnands, Rudy, Van Der Klis, Michiel, Belloni, Tomaso, Steeghs, Danny, ...
We present a variability study of the black hole candidate and X-ray transient H1743-322 during its 2003/2004 outburst. We analyzed five Rossi X-ray Timing Explorer observations that were performed...
Wijnands, Rudy, Homan, Jeroen, Heinke, Craig O., Miller, Jon M., Lewin, Walter H. G.
(Abridge) We observed the accreting millisecond X-ray pulsars XTE J0929-314 and XTE J1751-305 in their quiescent states using Chandra. From XTE J0929-314 we detected 22 photons (0.3-8 keV) in 24.4...
Crust cooling curves of accretion-heated neutron stars (2004)
We discuss the recent efforts to use a sub-class of neutron-star X-ray transients (the quasi-persistent transients) to probe the properties of neutron-star crusts and cores. Quasi-persistent X-ray...
Observations of millisecond X-ray pulsars (2004)
I present an observational review of the five accretion-driven millisecond X-ray pulsars currently known, focusing on the results obtained with the Rossi X-ray Timing Explorer (RXTE) satellite. A...
The crust cooling curve of the neutron star in MXB 1659-29 (2004)
We have monitored the quasi-persistent neutron-star X-ray transient MXB 1659-29 in quiescence using Chandra. The purpose of our observations was to monitor the quiescent behavior of the source after...
The crust cooling curve of the neutron star in mxb 1659-29 (2004)
Hemos monitoreado con Chandra MXB 1659-29, un sistema transitorio en rayos X, en su etapa de quietud. El propósito de nuestras observaciones es documentar el comportamiento de este objeto en su...
Wijnands, Rudy, Homan, Jeroen, Miller, Jon M., Lewin, Walter H. G.
We have observed the quasi-persistent neutron-star X-ray transient and eclipsing binary MXB 1659-29 in quiescence on three occasions with Chandra. The purpose of our observations was to monitor the...
Homan, Jeroen, Wijnands, Rudy, Berg, Maureen Van Den
We present an analysis of XMM-Newton light curves of the dipping, bursting, and eclipsing low-mass X-ray binary EXO 0748-676, focusing on the variability on time scales of seconds to hours. The...
Wijnands, Rudy, Heinke, Craig O., Pooley, David, Edmonds, Peter D., Lewin, Walter H. G., Grindlay, Jonathan E., ...
We present a Chandra observation of the globular cluster Terzan 5 during times when the neutron-star X-ray transient EXO 1745-248 located in this cluster was in its quiescent state. We detected the...
Chandra Detections of Two Quiescent Black Hole X-Ray Transients (2003)
Tomsick, John A., Corbel, Stephane, Fender, Rob, Miller, Jon M., Orosz, Jerome A., Rupen, Michael P., ...
Using the Chandra X-ray Observatory, we have detected the black hole transients V4641 Sgr and XTE J1859+226 in their low luminosity, quiescent states. The 0.3-8 keV luminosities are...
An observational review of accretion-driven millisecond X-ray pulsars (2003)
I present an observational review of the five currently known accretion-driven millisecond X-ray pulsars. A prominent place in this review is given to SAX J1808.4-3658; it was the first such system...
Simultaneous radio and X-ray observations of the low-mass X-ray binary GX 13+1 (2003)
Homan, Jeroen, Wijnands, Rudy, Rupen, Michael P., Fender, Rob, Hjellming, Robert M., Di Salvo, Tiziana, ...
We present the results of two simultaneous X-ray/radio observations of the low-mass X-ray binary GX 13+1, performed in July/August 1999 with the Rossi X-ray Timing Explorer and the Very Large Array....
Quasi-periodic X-ray brightness fluctuations in an accreting millisecond pulsar (2003)
Wijnands, Rudy, Van Der Klis, Michiel, Homan, Jeroen, Chakrabarty, Deepto, Markwardt, Craig B., Morgan, Ed H.
The relativistic plasma flows onto neutron stars that are accreting material from stellar companions can be used to probe strong-field gravity as well as the physical conditions in the...
Nuclear-Powered Millisecond Pulsars and the Maximum Spin Frequency of Neutron Stars (2003)
Chakrabarty, Deepto, Morgan, Edward H., Muno, Michael P., Galloway, Duncan K., Wijnands, Rudy, Van Der Klis, Michiel, ...
Millisecond pulsars are neutron stars (NSs) that are thought to have been spun-up by mass accretion from a stellar companion. It is unknown whether there is a natural brake for this process, or if it...
High frequency quasi-periodic oscillations in the black hole X-ray transient XTE J1650-500 (2002)
Homan, Jeroen, Klein-Wolt, Marc, Rossi, Sabrina, Miller, Jon M., Wijnands, Rudy, Belloni, Tomaso, ...
We report the detection of high frequency variability in the black hole X-ray transient XTE J1650-500. A quasi-periodic oscillation (QPO) was found at 250 Hz during a transition from the hard to the...
X-Ray Jet Emission from the Black Hole X-Ray Binary XTE J1550-564 with Chandra in 2000 (2002)
Tomsick, John A., Corbel, Stephane, Fender, Rob, Miller, Jon M., Orosz, Jerome A., Tzioumis, Tasso, ...
We have discovered an X-ray jet due to material ejected from the black hole X-ray transient XTE J1550-564. The discovery was first reported by Corbel et al. (Science, 298, 196 and astro-ph/0210224),...
A XMM-Newton observation during the 2000 outburst of SAX J1808.4-3658 (2002)
I present a XMM-Newton observation of the accretion driven millisecond X-ray pulsar SAX J1808.4-3658 during its 2000 outburst. The source was conclusively detected, albeit at a level of only ~2 x...
Wijnands, Rudy, Nowak, Mike, Miller, Jon M., Homan, Jeroen, Wachter, Stefanie, Lewin, Walter H. G.
After almost 2.5 years of actively accreting, the neutron star X-ray transient and eclipsing binary MXB 1659-29 returned to quiescence in 2001 September. We report on a Chandra observation of this...
XMM-Newton observations of the neutron star X-ray transient KS 1731-260 in quiescence (2002)
Wijnands, Rudy, Guainazzi, Matteo, Van Der Klis, Michiel, Mendez, Mariano
We report on XMM-Newton observations performed on 2001 September 13-14 of the neutron star X-ray transient KS 1731-260 in quiescence. The source was detected at an unabsorbed 0.5-10 keV flux of only...
Wijnands, Rudy, Miller, J. M., Wang, Q. Daniel
We present Chandra/ACIS observations of the bursting X-ray transient SAX J1747.0-2853 performed on 18 July 2001. We detected a bright source at the position of R.A = 17^h 47^m 02.60^s and Dec. = -28...
A Chandra observation of GRO J1744-28: the bursting pulsar in quiescence (2002)
Wijnands, Rudy, Wang, Q. Daniel
We present a Chandra/ACIS-I observation of GRO J1744-28. We detected a source at a position of R.A = 17h 44m 33.09s and Dec. = -28degr 44' 27.0'' (J2000.0; with a 1sigma error of ~0.8 arcseconds),...
Wijnands, Rudy, Heinke, Craig O., Grindlay, Jonathan E.
We present a short (~3.6 ks) Chandra/HRC-I observation of the globular cluster Terzan 1. This cluster is known to contain the bright neutron star low-mass X-ray binary X 1732-304 which was active...
I will briefly discuss the implications of the recent quiescent Chandra observation of the long-duration neutron star transient KS 1731-260 (Wijnands et al. 2001a) on models for quiescent systems...
Wijnands, Rudy, Miller, Jon M., Markwardt, Craig, Lewin, Walter H. G., Van Der Klis, Michiel
After more than a decade of actively accreting at about a tenth of the Eddington critical mass accretion rate, the neutron-star X-ray transient KS 1731-260 returned to quiescence in early 2001. We...
Mukai, Koji, Smale, Alan P., Stahle, Caroline K., Schlegel, Eric M., Wijnands, Rudy
MS 1603.6+2600 is a high-latitude X-ray binary with a 111 min orbital period, thought to be either an unusual cataclysmic variable or an unusual low-mass X-ray binary. In an ASCA observation in 1997...
The erratic luminosity behavior of SAX J1808.4-3658 during its 2000 outburst (2001)
Wijnands, Rudy, Mendez, Mariano, Markwardt, Craig, Van Der Klis, Michiel, Chakrabarty, Deepto, Morgan, Ed
We report on the highly variable and erratic long-term X-ray luminosity behavior of the only known accretion-driven millisecond X-ray pulsar SAX J1808.4-3658 during its 2000 outburst, as observed...
Wijnands, Rudy, Kuiper, Lucien, Zand, Jean In 't, Dotani, Tadayasu, Van Der Klis, Michiel, Heise, John
We have observed the millisecond X-ray pulsar SAX J1808.4-3658 on three occasions during its 2000 outburst with the BeppoSAX satellite. The source was highly variable and erratic during this...
Wijnands, Rudy, Miller, Jon M.
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...
Wijnands, Rudy, Mendez, Mariano, Miller, Jon M., Homan, Jeroen
We present a detailed study of the 5 Hz quasi-periodic oscillation (QPO) recently discovered in the bright X-ray transient and black-hole candidate GRS 1739-278 (Borozdin & Trudolyubov 2000) during a...
4U 1957+11: a persistent low-mass X-ray binary and black-hole candidate in the high state? (2001)
Wijnands, Rudy, Miller, Jon M., Van Der Klis, Michiel
We report on several pointed Rossi X-ray Timing Explorer observations of the enigmatic low-mass X-ray binary (LMXB) 4U 1957+11 at different X-ray luminosities. The luminosity of the source varied by...
Homan, Jeroen, Van Der Klis, Michiel, Jonker, Peter G., Wijnands, Rudy, Kuulkers, Erik, Mendez, Mariano, ...
We have analyzed ~600 ks of Rossi X-ray Timing Explorer data of the neutron star low-mass X-ray binary and Z source GX 17+2. A study was performed of the properties of the noise components and...
Recurrent very-long type-I X-ray bursts in the low-mass X-ray binary 4U 1636-53 (2001)
Two flares with a duration of several hours are reported for the low-mass X-ray binary 4U 1636-53. The characteristics of these flares (i.e., decay time scales, spectral softening, fluences) are very...
Normal-Branch Quasi-Periodic Oscillations during the High Intensity State of Cygnus X-2 (2000)
Wijnands, Rudy, Van Der Klis, Michiel
Using data obtained with the Rossi X-ray Timing Explorer, we report the detection of a 5 Hz quasi-periodic oscillation (QPO) in the bright low-mass X-ray binary and Z source Cygnus X-2 during high...
Dotani, Tadayasu, Asai, Kazumi, Wijnands, Rudy
The accretion-powered millisecond X-ray pulsar, SAX J1808.4-3658, was observed in quiescence with ASCA in September 1999. We detected a dim X-ray source in the SIS data at the position consistent to...
Wijnands, Rudy, Strohmayer, Tod, Franco, Lucia M.
We report the discovery of nearly coherent oscillations with a frequency of 567 Hz during type-I X-ray bursts from the X-ray transient and eclipsing binary X 1658-298. If these oscillations are...
Quasi-periodic oscillations and noise in neutron star and black-hole X-ray binaries (2000)
Before the launch of the Rossi X-ray Timing Explorer (RXTE) satellite, the differences in the rapid X-ray variability between the two main types of neutron star binaries (i.e., the Z and atoll...
Ford, Eric C., Van Der Klis, Michiel, Mendez, Mariano, Wijnands, Rudy, Homan, Jeroen, Jonker, Peter G., ...
We measure simultaneously the properties of the energy spectra and the frequencies of the kilohertz quasi-periodic oscillations (QPOs) in fifteen low mass X-ray binaries covering a wide range of...
The power spectral properties of the Z-source GX 340+0 (2000)
Jonker, Peter G., Van Der Klis, Michiel, Wijnands, Rudy, Homan, Jeroen, Van Paradijs, Jan, Mendez, Mariano, ...
We present an analysis of ~390 ksec of data of the Z source GX 340+0 taken during 24 observations with the Rossi X-ray Timing Explorer satellite. We report the discovery of a new broad component in...
Homan, Jeroen, Wijnands, Rudy, Van Der Klis, Michiel, Belloni, Tomaso, Van Paradijs, Jan, Klein-Wolt, Marc, ...
We present an analysis of RXTE data of the X-ray transient XTE J1550-564. The source went through several states, which were divided into spectrally soft and hard states. These states showed up as...
Discovery of a ~1 Hz quasi-periodic oscillation in the low-mass X-ray binary 4U 1746-37 (1999)
Jonker, Peter G., Van Der Klis, Michiel, Homan, Jeroen, Wijnands, Rudy, Van Paradijs, Jan, Mendez, Mariano, ...
We have discovered a ~1 Hz quasi-periodic oscillation (QPO) in the persistent X-ray emission and during type I X-ray bursts of the globular cluster source, dipper and low-mass X-ray binary (LMXB) 4U...
The rapid X-ray variability of V4641 Sagittarii (SAX J1819.3-2525 = XTE J1819-254) (1999)
Wijnands, Rudy, Van Der Klis, Michiel
We report on the rapid X-ray variability of the variable star and X-ray transient V4641 Sagittarii (SAX J1819.3-2525; XTE J1819-254) as observed on 15 Sept. 1999 by the proportional counter array...
Wijnands, Rudy, Homan, Jeroen, Van Der Klis, Michiel
We present a study of the complex phase lag behavior of the low-frequency (
X-ray timing behaviour of Cygnus X-2 at low intensities (1999)
Kuulkers, Erik, Wijnands, Rudy, Van Der Klis, Michiel
It is known that the overall (mean) intensity of the low-mass X-ray binary Cyg X-2 varies on time scales from a day to months, independently from the variations on time scales of hours to a day by...
The X-ray Timing Behavior of the X-ray Burst Source SLX 1735-269 (1999)
Wijnands, Rudy, Van Der Klis, Michiel
We report for the first time on the rapid X-ray variability of the galactic bulge source and X-ray burster SLX 1735-269. The power spectrum as observed with the Rossi X-ray Timing Explorer is...
Homan, Jeroen, Jonker, Peter G., Wijnands, Rudy, Van Der Klis, Michiel, Van Paradijs, Jan
We report the discovery of a quasi-periodic oscillation (QPO) in data obtained with the Rossi X-ray Timing Explorer of the dipping and eclipsing low-mass X-ray binary EXO 0748-676. The QPO had a...
Psaltis, Dimitrios, Wijnands, Rudy, Homan, Jeroen, Jonker, Peter G., Van Der Klis, Michiel, Miller, M. Coleman, ...
We study the horizontal branch oscillations (HBO) and the two simultaneous kilohertz QPOs comparing their properties in five Z sources with the predictions of the magnetospheric beat-frequency and...
The discovery of a 7-14 Hz Quasi-Periodic Oscillation in the X-ray Transient XTE J1806-246 (1999)
Wijnands, Rudy, Van Der Klis, Michiel
We have studied the correlated X-ray spectral and X-ray timing behavior of the X-ray transient XTE J1806-246 using data obtained with the proportional counter array onboard the Rossi X-ray Timing...
Homan, Jeroen, Mendez, Mariano, Wijnands, Rudy, Van Der Klis, Michiel, Van Paradijs, Jan
We report the discovery of twin kHz quasi-periodic oscillations (QPOs) in the persistent X-ray flux of the new X-ray transient XTE J2123-058. We detected the QPOs in data taken with the proportional...
Wijnands, Rudy, Van Der Klis, Michiel, Rijkhorst, Erik-Jan
We have discovered a 7.06+-0.08 Hz quasi-periodic oscillation (QPO) in the X-ray flux of the low-luminosity low-mass X-ray binary (LMXB) and atoll source 4U 1820-30. This QPO was only observable at...
A persistent ~1 Hz quasi-periodic oscillation in the dipping low-mass X-ray binary 4U 1323-62 (1998)
Jonker, Peter G., Van Der Klis, Michiel, Wijnands, Rudy
We have discovered a ~1 Hz quasi-periodic oscillation (QPO) in the persistent-emission, the dips, and the type I X-ray bursts of the low-mass X-ray binary 4U 1323-62. The rms amplitude of the QPO is...
Mendez, Mariano, Van Der Klis, Michiel, Ford, Eric C., Wijnands, Rudy, Van Paradijs, Jan
We present new results based on observations carried out with the Rossi X-ray Timing Explorer during the decay of an outburst of the low-mass X-ray binary (LMXB) and atoll source 4U 1608-52. Our...
The broad-band power spectra of X-ray binaries (1998)
Wijnands, Rudy, Van Der Klis, Michiel
We analyzed the rapid aperiodic X-ray variability of different types of X-ray binaries (black hole candidates, atoll sources, the recently discovered millisecond X-ray pulsar, and Z sources) at their...
Discovery of a Second Kilohertz QPO in the X-ray Binary 4U 1735-44 (1998)
Ford, Eric C., Van Der Klis, Michiel, Van Paradijs, Jan, Mendez, Mariano, Wijnands, Rudy, Kaaret, Philip
In recent observations with the Rossi X-Ray Timing Explorer we have detected two simultaneous quasi-periodic oscillation (QPO) peaks in the low mass X-ray binary and atoll source 4U 1735-44. The...
The broad-band power spectrum of SAX J1808.4-3658 (1998)
Wijnands, Rudy, Van Der Klis, Michiel
We analyzed the rapid aperiodic X-ray variability of the recently discovered millisecond X-ray pulsar SAX J1808.4-3658. The power density spectrum is dominated by a strong band-limited noise...
Mendez, Mariano, Van Der Klis, Michiel, Wijnands, Rudy, Ford, Eric C., Van Paradijs, Jan, Vaughan, Brian A.
We present new Rossi X-ray Timing Explorer observations of the low-mass X-ray binary 4U 1608-52 during the decay of its 1998 outburst. We detect by a direct FFT method the existence of a second...
Discovery of KiloHertz Quasi-Periodic Oscillations in the Z source GX 5-1 (1998)
Wijnands, Rudy, Mendez, Mariano, Van Der Klis, Michiel, Psaltis, Dimitrios, Kuulkers, Erik, Lamb, Frederick K.
We discovered two simultaneous kHz quasi-periodic oscillations (QPOs) in the bright low-mass X-ray binary and Z source GX 5-1 with the Rossi X-ray Timing Explorer. In the X-ray color-color and...
Discovery of the first accretion-powered millisecond X-ray pulsar (1998)
Wijnands, Rudy, Van Der Klis, Michiel
The precise origins of the millisecond radio pulsars, discovered in the early 1980s, remain uncertain until this day. They plausibly evolve from accreting low magnetic-field neutron stars in X-ray...
Discovery of kilohertz quasi-periodic oscillations in the Z source GX 340+0 (1998)
Jonker, Peter G., Wijnands, Rudy, Van Der Klis, Michiel, Psaltis, Dimitrios, Kuulkers, Erik, Lamb, Frederick K.
We have discovered two simultaneous kHz quasi-periodic oscillations (QPOs) in the Z source GX 340+0 with the Rossi X-ray Timing Explorer. The X-ray hardness-intensity and color-color diagram each...
Discovery of a 57-69 Hz quasi-periodic oscillation in GX13+1 (1998)
Homan, Jeroen, Van Der Klis, Michiel, Wijnands, Rudy, Vaughan, Brian, Kuulkers, Erik
We report the discovery of a quasi-periodic oscillation (QPO) at 61.0+/-1.7 Hz with the Rossi X-Ray Timing Explorer in the low-mass X-ray binary and persistently bright atoll source GX 13+1 (4U...
Discovery of KiloHertz Quasi-Periodic Oscillations in 4U 1735-44 (1998)
Wijnands, Rudy, Van Der Klis, Michiel, Mendez, Mariano, Van Paradijs, Jan, Lewin, Walter H. G., Lamb, Frederick K., ...
We discovered a single kHz quasi-periodic oscillation (QPO) near 1150 Hz in the Rossi X-ray Timing Explorer X-ray light curve of the low mass X-ray binary and atoll source 4U 1735-44. The rms...
Wijnands, Rudy, Van Der Klis, Michiel
We have discovered kiloHertz quasi-periodic oscillations (kHz QPOs) in five Z sources: GX 340+0, Cygnus X-2, GX 17+2, GX 5-1, and Scorpius X-1. In all sources the properties of these kHz QPOs are...
Absorption dips in GRO J1655-40: mapping the inner accretion disk (1997)
Kuulkers, Erik, Wijnands, Rudy, Belloni, Tomaso, Mendez, Mariano, Van Der Klis, Michiel, Van Paradijs, Jan
Using the RXTE PCA we discovered dips in the X-ray light curves of the black-hole candidate GRO J1655-40 during outburst. They are short (~minute) and deep (down to ~8% of the out-of-dip intensity)....
Discovery of KiloHertz Quasi-Periodic Oscillations in the Z source Cygnus X-2 (1997)
Wijnands, Rudy, Homan, Jeroen, Van Der Klis, Michiel, Kuulkers, Erik, Van Paradijs, Jan, Lewin, Walter H. G., ...
During observations with RXTE we discovered two simultaneous kHz QPOs near 500 Hz and 860 Hz in the Z source Cyg X-2. In the X-ray color-color diagram and hardness-intensity diagram (HID) a clear Z...
Non-detection of kHz QPOs in GX 9+1 and GX 9+9 (1997)
Wijnands, Rudy, Van Der Klis, Michiel, Van Paradijs, Jan
In numerous low-mass X-ray binaries kHz quasi-periodic oscillations (kHz QPOs) are detected. We observed the atoll sources GX 9+1 and GX 9+9 with the RXTE satellite. Both sources were on the (upper)...
KiloHertz Quasi-Periodic Oscillations in GX 17+2 (1997)
Wijnands, Rudy, Homan, Jeroen, Van Der Klis, Michiel, Mendez, Mariano, Kuulkers, Erik, Van Paradijs, Jan, ...
We observed the low-mass X-ray binary and Z source GX 17+2 with the Rossi X-ray Timing Explorer during 6-8 Feb 1997, 1-4 Apr 1997, and 26-27 Jul 1997. The X-ray color-color diagram shows a clear Z...
Discovery of microsecond time lags in kilohertz QPO (1997)
Vaughan, Brian A., Van Der Klis, Michiel, Mendez, Mariano, Van Paradijs, Jan, Wijnands, Rudy, Lewin, Walter H. G., ...
Using the Rossi X-ray Timing Explorer we have measured 27 microsecond time delays in 830 Hz quasi-periodic oscillations (QPO) between 4-6 keV and 11-17 keV in 4U 1608-52, with high-energy photons...