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...
Discovery of the Spin Frequency of 4U 0614+09 with SWIFT/BAT (2007)
Strohmayer, Tod, Markwardt, Craig, Kuulkers, Erik
We report the discovery of burst oscillations at 414.7 Hz during a thermonuclear X-ray burst from the low mass X-ray binary (LMXB) 4U 0614+091 with the Burst Alert Telescope (BAT) onboard SWIFT. In a...
X-ray properties of an Unbiased Hard X-ray Detected Sample of AGN (2007)
Winter, Lisa M., Mushotzky, Richard F., Tueller, Jack, Markwardt, Craig
The SWIFT gamma ray observatory's Burst Alert Telescope (BAT) has detected a sample of active galactic nuclei (AGN) based solely on their hard X-ray flux (14-195 keV). In this paper, we present for...
Ueda, Yoshihiro, Eguchi, Satoshi, Terashima, Yuichi, Mushotzky, Richard, Tueller, Jack, Markwardt, Craig, ...
We present the Suzaku broad band observations of two AGNs detected by the Swift/BAT hard X-ray (>15 keV) survey that did not have previous X-ray data, Swift J0601.9-8636 and Swift J0138.6-4001. The...
A BeppoSAX-WFC viewpoint of new INTEGRAL sources, particularly IGR J17544-2619 (2004)
Zand, Jean In 't, Heise, John, Ubertini, Pietro, Bazzano, Angela, Markwardt, Craig
Of the 21 new sources that INTEGRAL discovered up to Feb. 1, 2004, five were detected with the BeppoSAX Wide Field Cameras at earlier times. IGR J16320-4751 appears to be a persistently active X-ray...
The Pulsed Spectra of Two Extraordinary Pulsars (2004)
Roberts, Mallory S. E., Ransom, Scott M., Gavriil, Fotis, Kaspi, Victoria M., Woods, Pete, Ibrahim, Alaa, ...
We report on X-ray monitoring of two isolated pulsars within the same RXTE field of view. PSR J1811-1925 in the young supernova remnant G11.2-0.3 has a nearly sinusoidal pulse profile with a hard...
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...
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...
Disk and Coronal Instabilities in GRS 1915+105 (1998)
Swank, Jean, Chen, Xingming, Markwardt, Craig, Taam, Ronald
We present time-resolved GRS 1915+105 energy and power spectra observed by RXTE, during an episode where the X-ray intensity makes an extreme dip. If the spectra are modeled in terms of disk and...