Orbital Period Determinations for Four SMC Be/X-ray Binaries

We present an optical and X-ray study of four Be/X-ray binaries located in the Small Magellanic Cloud (SMC). OGLE I-band data of up to 11 years of semi-continuous monitoring has been analysed for SMC X-2, SXP172 and SXP202B, providing both a measurement of the orbital period (Porb = 18.62, 68.90, and 229.9 days for the pulsars respectively) and a detailed optical orbital profile for each pulsar. For SXP172 this has allowed a direct comparison of the optical and X-ray emission seen through regular RXTE monitoring, revealing that the X-ray outbursts precede the optical by around 7 days. Recent X-ray studies by XMM-Newton have identified a new source in the vicinity of SXP15.3 raising doubt on the identification of the optical counterpart to this X-ray pulsar. Here we present a discussion of the observations that led to the proposal of the original counterpart and a detailed optical analysis of the counterpart to the new X-ray source, identifying a 21.7 d periodicity in the OGLE I-band data. The optical characteristics of this star are consistent with that of a SMC Be/X-ray binary. However, this star was rejected as the counterpart to SXP15.3 in previous studies due to the lack of H{\alpha} emission.Comment: Accepted for publication in MNRAS, 11 pages, 17 figure

Lebensqualität bei deutschsprachigen Patienten mit Rückenmarkverletzungen und Blasenfunktionsstörungen: Validierung der deutschen Adaption des Qualiveen®-Fragebogens

Zusammenfassung: Hintergrund: Blasenfunktionsstörungen bei Rückenmarkverletzten können zu erheblichen Einschränkungen der Lebensqualität führen. Zur Erfassung existiert ein validierter Fragebogen in französischer Sprache. Ziel war es, den Fragebogen in deutscher Sprache zu validieren. Material und Methoden: Übersetzung, sprachliche und interkulturelle Adaption erfolgten in Kooperation mit einer Forschungsstelle für Gesundheitssystemforschung. Die so entstandene Version wurde von 439Patienten an 18 Zentren in Deutschland, Österreich und der Schweiz ausgefüllt. Die Daten wurden deskriptiv hinsichtlich klinischer und soziodemographischer Charakteristika ausgewertet. Die Gütekriterien der Items und Skalen wurden mit einer detaillierten Skalenanalyse geprüft. Ergebnisse: Die Stichprobe bestand aus 65,8% Paraplegikern und 32,8% Tetraplegikern. Interne Konsistenz, Reliabilität und Validität des Fragebogens waren sehr gut. Differenzielle Effekte in den erhobenen klinischen Variablen wurden sichtbar. Schlussfolgerungen: Der Qualiveen®-Fragebogen steht als erstes Instrument in deutscher Sprache zur Untersuchung des Einflusses von Blasenfunktionsstörungen auf die Lebensqualität bei Rückenmarkverletzten zur Verfügun

Relativistic iron K X-ray Reverberation in NGC 4151

Recent X-ray observations have enabled the study of reverberation delays in AGN for the first time. All the detections so far are in sources with a strong soft excess, and the measured delay is between the hard (1-3 keV) direct continuum and the soft excess (0.5-1 keV), interpreted as the reflection continuum smeared by relativistic effects. There is however an inherent ambiguity in identifying and studying the details of the lines in the soft excess. Here we report the first detection of reverberation in the iron K band in any AGN. Using XMM-Newton observations of NGC 4151, we find delays of order 2000 s on time-scales of 10e5 s between the 5-6 keV band and 2-3 and 7-8 keV bands, with a broad lag profile resembling a relativistically-broadened iron line. The peak of the lag spectra shifts to lower energies at higher frequencies, consistent with the red wing of the line being emitted at smaller radii, as expected from reflection off the inner accretion disk. This is a first detection of a broad iron line using timing studies.Comment: final version, corrected small typo

Cortical substrate of bladder control in SCI and the effect of peripheral pudendal stimulation

We investigate (i) the central representation of lower urinary tract (LUT) control and (ii–iii) the acute and 23 short-term central neuromodulatory effect of peripheral pudendal nerve stimulation in incomplete spinal 24 cord injured (SCI) patients using functional magnetic resonance imaging (fMRI). The urinary bladder of eight 25 SCI patients has been passively filled and emptied using a catheter, to identify the neural substrate of bladder 26 control (i), and with simultaneous peripheral pudendal nerve stimulation to investigate its acute central 27 neuromodulatory effect (ii). To identify the potential effects of pudendal nerve stimulation treatment (iii), 28 six patients underwent a 2-week training using pudendal nerve stimulation followed by another fMRI 29 session of bladder filling. The pre- and post-training fMRI results have been compared and correlated with 30 the patient's pre- and post-training urological status. Our results suggest that the central representation of 31 bladder filling sensation is preserved in the subacute stage of incomplete SCI. However, compared to earlier 32 data from healthy subjects, it shows decreased neural response in right prefrontal areas and increased in left 33 prefrontal regions, indicating diminished inhibitory micturition control as well as, compensatory or de- 34 compensatory reorganization of bladder control. We also provide evidence for a neuromodulatory effect of 35 acute pudendal nerve stimulation, which was most prominent in the right posterior insula, a brain region 36 implicated in homeostatic interoception in human. Pudendal stimulation training also induced significant 37 neuromodulation, predominantly signal increases, in the normal cortical network of bladder control. 38 Correlations with the patient's urological status indicate that this neuromodulatory effect may reflect the 39 clinical improvement following training

A return to strong radio flaring by Circinus X-1 observed with the Karoo Array Telescope test array KAT-7

Circinus X-1 is a bright and highly variable X-ray binary which displays strong and rapid evolution in all wavebands. Radio flaring, associated with the production of a relativistic jet, occurs periodically on a ~17-day timescale. A longer-term envelope modulates the peak radio fluxes in flares, ranging from peaks in excess of a Jansky in the 1970s to an historic low of milliJanskys during the years 1994 to 2007. Here we report first observations of this source with the MeerKAT test array, KAT-7, part of the pathfinder development for the African dish component of the Square Kilometre Array (SKA), demonstrating successful scientific operation for variable and transient sources with the test array. The KAT-7 observations at 1.9 GHz during the period 13 December 2011 to 16 January 2012 reveal in temporal detail the return to the Jansky-level events observed in the 1970s. We compare these data to contemporaneous single-dish measurements at 4.8 and 8.5 GHz with the HartRAO 26-m telescope and X-ray monitoring from MAXI. We discuss whether the overall modulation and recent dramatic brightening is likely to be due to an increase in the power of the jet due to changes in accretion rate or changing Doppler boosting associated with a varying angle to the line of sight.Comment: 7 pages, 5 figures, accepted for publication in MNRAS 14 May 201

Optical Follow-up of New SMC Wing Be/X-ray Binaries

We investigate the optical counterparts of recently discovered Be/X-ray binaries in the Small Magellanic Cloud. In total four sources, SXP101, SXP700, SXP348 and SXP65.8 were detected during the Chandra Survey of the Wing of the SMC. SXP700 and SXP65.8 were previously unknown. Many optical ground based telescopes have been utilised in the optical follow-up, providing coverage in both the red and blue bands. This has led to the classification of all of the counterparts as Be stars and confirms that three lie within the Galactic spectral distribution of known Be/X-ray binaries. SXP101 lies outside this distribution becoming the latest spectral type known. Monitoring of the Halpha emission line suggests that all the sources bar SXP700 have highly variable circumstellar disks, possibly a result of their comparatively short orbital periods. Phase resolved X-ray spectroscopy has also been performed on SXP65.8, revealing that the emission is indeed harder during the passage of the X-ray beam through the line of sight.Comment: 9 pages, 9 figures, 2 tables, accepted for publication in MNRA