The eROSITA X-ray telescope on SRG Predehl, P.; Andritschke, R.; Arefiev, V. ...
Astronomy and astrophysics (Berlin),
03/2021, Volume:
647, Issue:
A1
Journal Article
Peer reviewed
Open access
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the primary instrument on the Spectrum-Roentgen-Gamma (SRG) mission, which was successfully launched on July 13, 2019, from the ...Baikonour cosmodrome. After the commissioning of the instrument and a subsequent calibration and performance verification phase, eROSITA started a survey of the entire sky on December 13, 2019. By the end of 2023, eight complete scans of the celestial sphere will have been performed, each lasting six months. At the end of this program, the eROSITA all-sky survey in the soft X-ray band (0.2–2.3 keV) will be about 25 times more sensitive than the ROSAT All-Sky Survey, while in the hard band (2.3–8 keV) it will provide the first ever true imaging survey of the sky. The eROSITA design driving science is the detection of large samples of galaxy clusters up to redshifts
z
> 1 in order to study the large-scale structure of the universe and test cosmological models including Dark Energy. In addition, eROSITA is expected to yield a sample of a few million AGNs, including obscured objects, revolutionizing our view of the evolution of supermassive black holes. The survey will also provide new insights into a wide range of astrophysical phenomena, including X-ray binaries, active stars, and diffuse emission within the Galaxy. Results from early observations, some of which are presented here, confirm that the performance of the instrument is able to fulfil its scientific promise. With this paper, we aim to give a concise description of the instrument, its performance as measured on ground, its operation in space, and also the first results from in-orbit measurements.
The Swift X-ray telescope BURROWS, David N; HILL, J. E; CHINCARINI, G ...
Space science reviews,
10/2005, Volume:
120, Issue:
3-4
Journal Article
Peer reviewed
he Swift Gamma-Ray Explorer is designed to make prompt multiwavelength observations of gamma-ray bursts (GRBs) and GRB afterglows. The X-ray telescope (XRT) enables Swift to determine GRB positions ...with a few arcseconds accuracy within 100 s of the burst onset. The XRT utilizes a mirror set built for JET-X and an XMM-Newton/EPIC MOS CCD detector to provide a sensitive broad-band (0.2-10 keV) X-ray imager with effective area of > 120 cm^sup 2^ at 1.5 keV, field of view of 23.6 × 23.6 arcminutes, and angular resolution of 18 arcseconds (HPD). The detection sensitivity is 2×10^sup -14^ erg cm^sup -2^ s^sup -1^ in 10^sup 4^ s. The instrument is designed to provide automated source detection and position reporting within 5 s of target acquisition. It can also measure the redshifts of GRBs with Fe line emission or other spectral features. The XRT operates in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize the science return for each frame as the source intensity fades. The XRT will measure spectra and lightcurves of the GRB afterglow beginning about a minute after the burst and will follow each burst for days or weeks.PUBLICATION ABSTRACT
Summary
Background.
This is a prospective study of patients with degenerative cervical disease who underwent ventral discectomy and disc replacement with the Bryan
®
cervical disc prosthesis. The ...objective was to investigate clinical outcome at 2 years of patients implanted with the Bryan
®
disc and to evaluate function of the implant itself.
Methods.
Fifty-four consecutive patients with cervical disc herniation and/or spondylosis with preserved mobility in the affected spinal segments were enrolled. Patients presented clinically with cervical radiculopathy and/or myelopathy with or without neck pain. A standard anterior cervical discectomy was carried out and a Bryan
®
disc was implanted in the affected levels. A total of 59 prosthetic discs were implanted, in 49 patients at a single level and in 5 at two adjacent levels. The neurological status was evaluated pre-operatively and at one and two years thereafter. Plain X-rays, CT, and MRI were used for pre-operative diagnostics. Post-operative follow-up was done by X-rays.
Findings.
All patients had an excellent or good neurological outcome according to the Odom criteria. Loss of function (motion range <3°) was found in 7 (12%) out of 59 Bryan
®
discs at two years after surgery. Heterotopic ossification (HO) of the McAffee grades 1–4 was seen in a total of 17 (29%) segments. There were no implant dislocations or migrations.
Conclusions.
Implantation of the Bryan
®
disc resulted in excellent or good neurological outcome in all patients. The surgical technique was safe and without complications. Twelve percent of the implanted Bryan
®
discs lost mobility at two years, mainly due to HO. A trend was seen towards development of HO in the operated segments.
Further investigations with longer follow-up periods and with a control group (e.g. fusion with intervertebral cage) will be necessary for a definitive assessment of the long-term functionality and benefits of artificial cervical discs.
Continuous intrathecal infusion of analgesic drugs by implantable pumps is recognized as an established treatment option for patients with chronic pain resistant to oral or parenteral medication. ...Polyanalgesia, the simultaneous use of more than one intrathecal analgesic drug, is practiced relatively often, but there are only a few published clinical studies on intrathecal polyanalgesia for chronic nonmalignant pain. This pilot study represents a long-term evaluation of a treatment regimen consisting of intrathecal morphine admixed with bupivacaine, clonidine, or midazolam in patients with chronic nonmalignant back and leg pain due to degenerative lumbar spinal disease. Twenty-six adult patients have been treated by intrathecal programmable pump-controlled infusion of analgesic drugs and followed for up to 3.5 years (27 ± 11 months). Combination of morphine with a second drug was used in 10 cases, morphine with 2 additional drugs in 12 cases, and morphine with 3 additional drugs in 4 cases. Mean daily doses at 24 months after pump implantation were 6.2 ± 2.8 mg for morphine, 2.5 ± 1.5 mg for bupivacaine, 0.06 ± 0.03 mg for clonidine, and 0.8 ± 0.4 mg for midazolam. Nineteen patients reported excellent or good long-term treatment results, 6 patients had sufficient results, and only 1 patient complained of poor therapeutic efficacy. No long-term clinical side effects of intrathecal polyanalgesia were noted. Mean morphine dose had to be increased from 1.2 mg at baseline to 5.1 mg at 24 months due to tolerance development and disease progression. This experience suggests that intrathecal polyanalgesia employing morphine combined with additional nonopioid drugs can have a favorable analgesic efficacy in patients with complex chronic pain of spinal origin, and lacks major drug-related complications.
We present the first X-ray spectrum obtained by the Low-Energy Transmission Grating Spectrometer (LETGS) aboard the Chandra X-Ray Observatory. The spectrum is of Capella and covers a wavelength range ...of 5-175 Å (2.5-0.07 keV). The measured wavelength resolution, which is in good agreement with ground calibration, is Deltalambda approximately 0.06 Å (FWHM). Although in-flight calibration of the LETGS is in progress, the high spectral resolution and unique wavelength coverage of the LETGS are well demonstrated by the results from Capella, a coronal source rich in spectral emission lines. While the primary purpose of this Letter is to demonstrate the spectroscopic potential of the LETGS, we also briefly present some preliminary astrophysical results. We discuss plasma parameters derived from line ratios in narrow spectral bands, such as the electron density diagnostics of the He-like triplets of carbon, nitrogen, and oxygen, as well as resonance scattering of the strong Fe xvii line at 15.014 Å.
Metastatic lesions are the most common spinal extradural tumours. Significant advances in their neurosurgical management have been made in the last two decades. This retrospective study was ...undertaken to summarise the long-term results of surgery and the outcome of patients with cervical spine metastases. Sixty-two patients with cervical spine metastases who underwent instrumented spinal surgery at a single centre in an 12-year period (1989-2000) were analysed. All patients presented with local pain and with either neurological deficits, spinal instability, or a combination of both. A standard anterior approach to the cervical spine was chosen, and a partial or total vertebrectomy and vertebral body replacement with subsequent anterior instrumented fusion were carried out in all cases. General and neurological status was evaluated at baseline and in regular intervals thereafter. Plain X-rays, CT, and MRI were used for preoperative planning. Postoperative follow-up was done by X-rays. The mean follow-up time for all patients was 1.5 years. A stable bony fusion of the cervical spine was achieved in 60 patients (96.8%), with two additional patients needing a further procedure for maintaining the mechanical stability of the spine. There was mild early surgery-related morbidity, and no mortality. The most frequent temporary surgery-related side effect was reversible vocal cord paresis in 5 cases (8.0%). There were 3 cases (4.8%) of early instrumentation failure. One of these was symptomatic and underwent second-look surgery. No late complications occurred due to instrumentation hardware failure. The 1-year survival rate of all patients after surgery was 58%, and the 2-year survival rate was 21%. Our results demonstrate that surgical removal of extradural metastases with subsequent instrumented fusion is a low-morbidity and low-complications procedure with high rates of permanent stabilisation of the compromised cervical spine. In addition, it improves the neurological deficits and relieves the local pain in a significant proportion of patients. Excellent local control of malignant disease can be achieved by the surgical procedure aided by subsequent local and systemic adjuvant therapy. Overall survival time and prognosis of the patients, however, are mainly depending on the type and the stage of the primary malignancy.
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