Context. The X-Ray Telescope (XRT) on board Swift was mainly designed to provide detailed position, timing and spectroscopic information on gamma-ray burst (GRB) afterglows. During the mission ...lifetime the fraction of observing time allocated to other types of source has been steadily increased. Aims. In this paper, we report on the results of the in-flight calibration of the timing capabilities of the XRT in Windowed Timing read-out mode. Methods. We use observations of the Crab pulsar to evaluate the accuracy of the pulse period determination by comparing the values obtained by the XRT timing analysis with the values derived from radio monitoring. We also check the absolute time reconstruction measuring the phase position of the main peak in the Crab profile and comparing it both with the value reported in literature and with the result that we obtain from a simultaneous Rossi X-Ray Timing Explorer (RXTE) observation. Results. We find that the accuracy in period determination for the Crab pulsar is of the order of a few picoseconds for the observation with the largest data time span. The absolute time reconstruction, measured using the position of the Crab main peak, shows that the main peak anticipates the phase of the position reported in literature for RXTE by ~270 μs on average (~150 μs when data are reduced with the attitude file corrected with the UVOT data). The analysis of the simultaneous Swift-XRT and RXTE proportional counter array (PCA) observations confirms that the XRT Crab profile leads the PCA profile by ~200 μs. The analysis of XRT photodiode mode data and BAT event data shows a main peak position in good agreement with the RXTE, suggesting the discrepancy observed in XRT data in Windowed Timing mode is likely due to a systematic offset in the time assignment for this XRT read out mode.
Constraining the energy budget of GRB 080721 STARLING, R. L. C; ROL, E; JAKOBSSON, P ...
Monthly notices of the Royal Astronomical Society,
2009, Letnik:
400, Številka:
1
Journal Article
The entire coding region of the TSC1 gene has been screened for
mutations in 79 unrelated patients
with tuberous sclerosis. Causative mutations have been found in 27 of these
patients and five other
...variations in the gene have been identified. 26 of the mutations are predicted
to cause premature
truncation of the protein product of the gene and one mutation is in a
splice site. The mutation screen
has revealed that TSC1 mutations are rarer in sporadic tuberous sclerosis
patients than in familial
cases. We have also found that the only previously described case of non-penetrance
can no longer
be described as such, and that a single ungual fibroma is not necessarily
diagnostic of tuberous
sclerosis, important findings for the genetic counselling of tuberous sclerosis
patients.
The Andromeda Galaxy recurrent nova M31N 2008-12a had been observed in eruption 10 times, including yearly eruptions from 2008 to 2014. With a measured recurrence period of Prec = 351+/-13 days (we ...believe the true value to be half of this) and a white dwarf very close to the Chandrasekhar limit, M31N 2008-12a has become the leading pre-explosion supernova type Ia progenitor candidate. Following multi-wavelength follow-up observations of the 2013 and 2014 eruptions, we initiated a campaign to ensure early detection of the predicted 2015 eruption, which triggered ambitious ground- and space-based follow-up programs. In this paper we present the 2015 detection, visible to near-infrared photometry and visible spectroscopy, and ultraviolet and X-ray observations from the Swift observatory. The LCOGT 2 m (Hawaii) discovered the 2015 eruption, estimated to have commenced at August 28.28 +/- 0.12 UT. The 2013-2015 eruptions are remarkably similar at all wavelengths. New early spectroscopic observations reveal short-lived emission from material with velocities approx. 13,000 km/s, possibly collimated outflows. Photometric and spectroscopic observations of the eruption provide strong evidence supporting a red giant donor. An apparently stochastic variability during the early supersoft X-ray phase was comparable in amplitude and duration to past eruptions, but the 2013 and 2015 eruptions show evidence of a brief flux dip during this phase. The multi-eruption Swift/XRT spectra show tentative evidence of high-ionization emission lines above a high-temperature continuum. Following Henze et al. (2015a), the updated recurrence period based on all known eruptions is Prec 174 +/- 10 days, and we expect the next eruption of M31N 2008-12a to occur around 2016 mid-September.
On 2020 February 24, during their third observing run ("O3"), the Laser Interferometer Gravitational-wave Observatory and Virgo Collaboration (LVC) detected S200224ca: a candidate gravitational wave ...(GW) event produced by a binary black hole (BBH) merger. This event was one of the best-localized compact binary coalescences detected in O3 (with 50%/90% error regions of 13/72 deg\(^2\)), and so the Neil Gehrels Swift Observatory performed rapid near-UV/X-ray follow-up observations. Swift-XRT and UVOT covered approximately 79.2% and 62.4% (respectively) of the GW error region, making S200224ca the BBH event most thoroughly followed-up in near-UV (u-band) and X-ray to date. No likely EM counterparts to the GW event were found by the Swift BAT, XRT, or UVOT, nor by other observatories. Here we report on the results of our searches for an EM counterpart, both in the BAT data near the time of the merger, and in follow-up UVOT/XRT observations. We also discuss the upper limits we can place on EM radiation from S200224ca, and the implications these limits have on the physics of BBH mergers. Namely, we place a shallow upper limit on the dimensionless BH charge, \(\hat{q} < 1.4 \times10^{-4}\), and an upper limit on the isotropic-equivalent energy of a blast wave \(E < 4.1\times10^{51}\) erg (assuming typical GRB parameters).
Polycystic disease has an early onset clinically and is the result of large contiguous deletions on chromosome 16 affecting both the TSC2 gene and the gene for adult onset polycystic kidney disease. ...2 Tuberous sclerosis complex exhibits genetic heterogeneity. 3 Mutations in two recently identified genes, TSC1 at 9q34 andTSC2 at 16p13, each result in an apparently similar phenotype, although recent work has suggested that mutations inTSC2 may be associated with more severe disease. 4 Both genes are tumour suppressor genes, the strongest evidence for this being the loss of heterozygosity around the normal gene at 9q34 or 16p13 in hamartomata from tuberous sclerosis patients. 5 6 There is evidence that the severity of learning difficulties in tuberous sclerosis complex is related to the number of hamartomata in the brain. 7 Until now, no one has reported on a correlation between the severity of the phenotype in two or more organs.
This paper argues for a standardized use of definitions and outcome measures in publications on West syndrome. Specific recommendations include the need for a validated definition of hypsarrhythmia, ...the use of the term non-symptomatic and abandoning the terms cryptogenic and idiopathic, talking about underlying disease association and not aetiology or cause and defining a clinical response to mean that no clinical evidence of a spasm has been seen for a specified time – 48 h was suggested. Patients should be followed up to report development – perhaps at 12–15 months and again at 2 and 5 years. Disease free survival should be reported. Side effects need to be seen as adverse events producing risk modification. Outcomes should be blind whenever possible. A consensus group will take these and other suggestions forward – please contact mailto:mpsjpo@bath.ac.uk if you are interested in taking part.
We present the Living Swift-XRT Point Source catalogue (LSXPS) and real-time transient detector. This system allows us for the first time to carry out low-latency searches for new transient X-ray ...events fainter than those available to the current generation of wide-field imagers, and report their detection in near real-time. Previously, such events could only be found in delayed searches, e.g. of archival data; our low-latency analysis now enables rapid and ongoing follow up of these events, enabling the probing of timescales previously inaccessible. The LSXPS is, uniquely among X-ray catalogues, updated in near real-time, making this the first up-to-date record of the point sources detected by a sensitive X-ray telescope: the Swift-X-ray Telescope (XRT). The associated upper limit calculator likewise makes use of all available data allowing contemporary upper limits to be rapidly produced on-demand. These facilities, which enable the low-latency transient system are also fully available to the community, providing a powerful resource for time-domain and multi-messenger astrophysics.
OBJECTIVES--To establish the frequency of fits and mental retardation in an unbiased group of tuberous sclerosis patients. METHODS--Known tuberous sclerosis families with more than one affected ...person were ascertained for a genetic linkage study. A number of members were born after genetic counselling had been given after identification of the proband. These subjects were then carefully examined clinically and in many cases with cranial computerised tomography, renal ultrasound, and skeletal survey but not echocardiography. They provide an unbiased group of tuberous sclerosis patients and allow affected patients with normal intellect to be diagnosed. PATIENTS--Thirty-seven tuberous sclerosis families were ascertained and 26 patients born after the family proband were identified. RESULTS--Sixteen of these 26 patients suffered fits (62%) and 10 patients were mentally retarded (38%). CONCLUSIONS--A lower incidence of fits and mental retardation has been found in an unbiased sample of tuberous sclerosis patients. The lifetime risk for fits might be higher had we been able to follow the patients for longer. However, we believe these are more appropriate figures to use in genetic counselling for this disease.
Long gamma-ray bursts (GRBs) are believed to originate from core collapse of massive stars. High-redshift GRBs can probe the star formation and reionization history of the early universe, but their ...detection remains rare. Here we report the detection of a GRB triggered in the 0.5--4 keV band by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated as EP240315a, whose bright peak was also detected by the Swift Burst Alert Telescope and Konus-Wind through off-line analyses. At a redshift of \(z=4.859\), EP240315a showed a much longer and more complicated light curve in the soft X-ray band than in gamma-rays. Benefiting from a large field-of-view (\(\sim\)3600 deg\(^2\)) and a high sensitivity, EP-WXT captured the earlier engine activation and extended late engine activity through a continuous detection. With a peak X-ray flux at the faint end of previously known high-\(z\) GRBs, the detection of EP240315a demonstrates the great potential for EP to study the early universe via GRBs.
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