14 research outputs found
X-ray monitoring of the radio and gamma-ray loud Narrow-Line Seyfert 1 Galaxy PKS 2004-447
We present preliminary results of the X-ray analysis of XMM-Newton and Swift
observations as part of a multi-wavelength monitoring campaign in 2012 of the
radio-loud narrow line Seyfert 1 galaxy PKS 2004-447. The source was recently
detected in gamma-rays by Fermi/LAT among only four other galaxies of that
type. The 0.5-10 keV X-ray spectrum is well-described by a simple absorbed
powerlaw (photon index ~ 1.6). The source brightness exhibits variability on
timescales of months to years with indications for spectral variability, which
follows a 'bluer-when-brighter' behaviour, similar to blazars.Comment: Proceedings for the 'Jet 2013' conference. Includes 3 pages, 3
figure
3D mapping of the neutral X-ray absorption in the local interstellar medium: The Gaia and XMM-Newton synergy
We present a three-dimensional map of the hydrogen density distribution in
the Galactic interstellar medium. The hydrogen equivalent column densities were
obtained from the Exploring the X-ray Transient and variable Sky project ({\sc
EXTraS}) which provides equivalent values from X-ray spectral fits
of observations within the {\it XMM-Newton} Data Release. {\sc EXTraS} include
multiple fits for each source, allowing an accurate determination of the
equivalent column densities, which depends on the continuum modeling of the
spectra. A cross-correlation between the {\sc EXTraS} catalogue and the first
{\it Gaia} Data Release was performed in order to obtain accurate parallax and
distance measurements. We use a Bayesian method explained in \citet{rez17} in
order to predict the most probable distribution of the density at any arbitrary
point, even for lines of sight along which there are no initial observation.
The resulting map shows small-scale density structures which can not been
modeled by using analytic density profiles. In this paper we present a proof of
concept of the kind of science possible with the synergy of these catalogs.
However, given the systematic uncertainties connected to the source
identification and to the dependence of on the spectral model, the
present maps should be considered qualitatively at this point
3D mapping of the neutral X-ray absorption in the local interstellar medium: the Gaia and XMM-Newton synergy
We present a three-dimensional map of the hydrogen density distribution in the Galactic interstellar medium. The hydrogen-equivalent column densities were obtained from the Exploring the X-ray Transient and variable Sky project (EXTRAS) which provides equivalent N_H values from X-ray spectral fits of observations within the XMM-Newton Data Release. EXTRAS include multiple fits for each source, allowing an accurate determination of the equivalent column densities, which depends on the continuum modelling of the spectra. A cross-correlation between the EXTRAS catalogue and the first Gaia Data Release was performed in order to obtain accurate parallax and distance measurements. We use a Bayesian method explained in Rezaei Kh. et al. (2017) in order to predict the most probable distribution of the density at any arbitrary point, even for lines of sight along which there are no initial observation. The resulting map shows small-scale density structures which could not have been modelled by using analytic density profiles. In this paper, we present a proof of concept of the kind of science possible with the synergy of these catalogues. However, given the systematic uncertainties connected to the source identification and to the dependence of N_H on the spectral model, the present maps should be considered qualitatively at this point
Development and Evaluation of an In-line and On-line Monitoring System for Granule Size Distributions in Continuous Roll Compaction/Dry Granulation Based on Laser Diffraction
<jats:title>Abstract</jats:title><jats:sec>
<jats:title>Purpose</jats:title>
<jats:p>Roll compaction/dry granulation is established in manufacturing of solid oral dosage forms and, within the context of continuous manufacturing, it has sparked interest as material is fed, processed, and ejected continuously while also providing large possible throughputs. However, this amount of material has to be adequately controlled in real time to assure quality.</jats:p>
</jats:sec><jats:sec>
<jats:title>Methods</jats:title>
<jats:p>This research aimed at monitoring the critical quality attribute granule size distribution in continuous roll compaction/dry granulation (QbCon®; L.B. Bohle, Ennigerloh, Germany) using in-line and on-line laser diffraction. The influence of varying process parameters and excipient formulations was studied and evaluated with the prospect of using this technique to develop control loops. For this purpose, residence time parameters were assessed. In- and on-line data was compared with off-line laser diffraction and dynamic image analysis data.</jats:p>
</jats:sec><jats:sec>
<jats:title>Results</jats:title>
<jats:p>The system successfully monitored the granule size distribution in a variety of process parameters and throughputs (up to 27.5 kg/h). It was sensitive to changes in process parameters and changes in material blends, which could pose a potential threat to the final drug products’ quality. Average event propagation time from the compaction zone to the laser diffraction system of 17.7 s demonstrates the systems’ fast reaction time.</jats:p>
</jats:sec><jats:sec>
<jats:title>Conclusion</jats:title>
<jats:p>Results highlight laser diffraction as a valuable method of in- and on-line size determination and allow for the development of a control strategy using this principle.</jats:p>
</jats:sec>
Implementing Feedback Granule Size Control in a Continuous Dry Granulation Line Using Controlled Impeller Speed of the Granulation Unit, Compaction Force and Gap Width
<jats:title>Abstract</jats:title><jats:sec>
<jats:title>Purpose</jats:title>
<jats:p>In continuous manufacturing of pharmaceuticals, dry granulation is of interest because of its large throughput capacity and energy efficiency. In order to manufacture solid oral dosage forms continuously, valid control strategies for critical quality attributes should be established. To this date, there are no published control strategies for granule size distribution in continuous dry granulation.</jats:p>
</jats:sec><jats:sec>
<jats:title>Methods</jats:title>
<jats:p>In-line laser diffraction was used to determine the size of granules in a continuous roll compaction/dry granulation line (QbCon® dry). Different process parameters were evaluated regarding their influences on granule size. The identified critical process parameters were then incorporated into control strategies. The uncontrolled and the controlled processes were compared based on the resulting granule size. In both processes, a process parameter was changed to induce a shift in median particle size and the controller had to counteract this shift.</jats:p>
</jats:sec><jats:sec>
<jats:title>Results</jats:title>
<jats:p>In principle, all process parameters that affect the median particle size could also be used to control the particle size in a dry granulation process. The sieve impeller speed was found to be well suited to control the median particle size as it reacts fast and can be controlled independently of the throughput or material.</jats:p>
</jats:sec><jats:sec>
<jats:title>Conclusion</jats:title>
<jats:p>The median particle size in continuous roll compaction can be controlled by adjusting process parameters depending on real-time granule size measurements. The method has to be validated and explored further to identify critical requirements to the material and environmental conditions.</jats:p>
</jats:sec>
Imaging with a multichannel terahertz time-domain spectroscopy system at 1030 nm excitation wavelength
We present Terahertz imaging with a 1D multichannel time-domain spectroscopy system (TDS) which operates with a photoconductive array of 15 detection channels excited by a 1030 nm femtosecond fiber laser. The emitter and detector are photoconductive antennas based on InGaAs/InAlAs multi-layer heterostructures (MLHS). The simultaneous measurement of 15 THz pulses with a pixel pitch of 1 mm increases the measurement speed by factor 15
Rapid variability of Markarian 421 during extreme flaring as seen through the eyes of XMM-Newton
By studying the variability of blazars across the electromagnetic spectrum, it is possible to resolve the underlying processes responsible for rapid flux increases, so-called flares. We report on an extremely bright X-ray flare in the high-peaked BL Lacertae object Markarian 421 (Mrk 421) that occurred simultaneously with enhanced γ-ray activity detected at very high energies by First G-APD Cherenkov Telescope on 2019 June 9. We triggered an observation with XMM-Newton, which observed the source quasi-continuously for 25 h. We find that the source was in the brightest state ever observed using XMM-Newton, reaching a flux of 2.8 × 10-9 over an energy range of 0.3-10 keV. We perform a spectral and timing analysis to reveal the mechanisms of particle acceleration and to search for the shortest source-intrinsic time-scales. Mrk 421 exhibits the typical harder-when-brighter behaviour throughout the observation and shows a clock-wise hysteresis pattern, which indicates that the cooling dominates over the acceleration process. While the X-ray emission in different sub-bands is highly correlated, we can exclude large time lags as the computed z-transformed discrete correlation functions are consistent with a zero lag. We find rapid variability on time-scales of 1 ks for the 0.3-10 keV band and down to 300 s in the hard X-ray band (4-10 keV). Taking these time-scales into account, we discuss different models to explain the observed X-ray flare, and find that a plasmoid-dominated magnetic reconnection process is able to describe our observation best.ISSN:0035-8711ISSN:1365-296
Multi-wavelength study of Mrk 421 during a TeV flare
The blazar Mrk 421 shows frequent, short flares in the TeV energy regime. Due to the fast nature of such episodes, we often fail to obtain sufficient simultaneous information about flux variations in several energy bands. To overcome this lack of multi-wavelength (MWL) coverage, especially for the pre- and post-flare periods, we have set up a monitoring program with the FACT telescope (TeV energies) and the Neil Gehrels Swift Observatory (X-rays). On 2019 June 9, Mrk 421 showed a TeV outburst reaching a flux level of more than two times the flux of the Crab Nebula at TeV energies. We acquired simultaneous data in the X-rays with additional observations by XMM-Newton and INTEGRAL. For the first time, we can study a TeV blazar in outburst taking advantage of highly sensitive X-ray data from XMM-Newton and INTEGRAL combined. Our data set is complemented by pointed radio observations by Effelsberg at GHz frequencies. We present our first results, including the gamma-ray and X-ray light curves, a timing analysis of the X-ray data obtained with XMM-Newton, as well as the radio spectra before, during and after the flare.ISSN:1824-803