scholarly journals A PROPOSED ITALIAN CONTRIBUTION FOR THE MIRAX SCIENTIFIC PAYLOAD

2012 ◽  
Vol 12 ◽  
pp. 110-119
Author(s):  
Y. EVANGELISTA ◽  
M. FEROCI ◽  
A. ARGAN ◽  
R. CAMPANA ◽  
E. COSTA ◽  
...  
Keyword(s):  
Energy Band ◽  
Broad Band ◽  
High Energy ◽  
Scientific Cooperation ◽  
X Ray ◽  
Scientific Mission ◽  
Energy Spectrometer ◽  
Coded Mask ◽  
Prompt Emission ◽  
Scientific Payload

Recent scientific cooperation between Italy and Brazil has opened the possibility of a significant Italian contribution to the scientific payload of the Brazilian mission MIRAX. MIRAX is a small scientific mission for X-ray astronomy, programmed for launch on 2015 on-board the Lattes satellite. The MIRAX scientific objectives include the broad-band study - inclusive of arcminute localisation - of the GRBs prompt emission, and the All Sky monitoring in the 2–50 keV energy band with a source location accuracy of a few arcmin and a daily sensitivity of 3 mCrab. The proposed configuration is composed of a coded-mask X-ray Monitor, equipped with Silicon Drift Detectors (2–50 keV), and a phoswich High Energy Spectrometer, sensitive in the 15–5000 keV energy band.

Microscintillator of Ce Doped β-NaLuF4 in Uniform Hexagonal Prism Morphology by a Facile Hydrothermal Method

2014 ◽  
Vol 541-542 ◽  
pp. 220-224
Author(s):  
Li Sha Liu ◽  
Hao Hong Chen ◽  
Bi Qiu Liu ◽  
Bin Tang ◽  
Zhi Jia Sun ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Hexagonal Phase ◽  
Broad Band ◽  
High Energy ◽  
Hexagonal Prism ◽  
Facile Hydrothermal Method ◽  
X Ray ◽  
Strong Broad Band ◽  
Broad Band Emission ◽  
Band Emission

To explore micro-or nanoscintillator with a controllable architecture, a novel facile hydrothermal method easy for commercial run was used to synthesize pure and Ce doped β-NaLuF4 microcrystals at 453K. The morphology of uniform hexagonal prism with 3.3μm in diameter and 1.4 μm in thickness, respectively, is presented by the results of scanning electron microscopy (SEM). Powder X-ray diffraction (PXRD) patterns show the products are both pure hexagonal phase. Different from the undoped product without any irradiation, the Ce doped product has given strong broad band emission attributed to 5d4f transition of Ce3+, which can be potentially used as scintillator for biomedical imaging and detectors for high energy such as X-ray and γray. This synthetical strategy extends the understanding about nanomaterial chemistry and can be also useful for other systems such as fluorides, oxides and sulfides.

scholarly journals Constraining X-ray emission in HBL blazars using multiwavelength observations

2020 ◽  
Vol 496 (2) ◽  
pp. 1295-1306
Author(s):  
Alicja Wierzcholska ◽  
Stefan J Wagner
Keyword(s):  
Spectral Energy Distribution ◽  
Broad Band ◽  
Neutral Hydrogen ◽  
High Energy ◽  
Host Galaxy ◽  
Spectral Energy ◽  
Additional Absorption ◽  
X Ray ◽  
Uv Excess ◽  
Survey Results

ABSTRACT The X-ray spectrum of extreme high-energy peaked BL Lac-type blazars is located in the synchrotron branch of the broad-band spectral energy distribution (SED), at energies below the peak. A joint fit of the extrapolated X-ray spectra together with a host galaxy template allows characterizing the synchrotron branch in the SED. The X-ray spectrum is usually characterized either with a pure or a curved power-law model. In the latter case, however, it is hard to distinguish an intrinsic curvature from excess absorption. In this paper, we focus on five well-observed blazars: 1ES 0229+200, PKS 0548−322, RX J 1136+6737, 1ES 1741+196, and 1ES 2344+514. We constrain the infrared to X-ray emission of these five blazars using a model that is characterized by the host galaxy, spectral curvature, absorption, and ultraviolet (UV) excess to separate these spectral features. In the case of four sources, namely 1ES 0229+200, PKS 0548−322, 1ES 1741+196, and 1ES 2344+514, the spectral fit with the atomic neutral hydrogen from the Leiden Argentina Bonn Survey results in a significant UV excess present in the broad-band SED. Such excess can be interpreted as an additional component, for example, a blue bump. However, in order to describe spectra of these blazars without such excess, additional absorption to the atomic neutral hydrogen from the Leiden Argentina Bonn Survey is needed.

scholarly journals The unusual broad-band X-ray spectral variability of NGC 1313 X-1 seen with XMM–Newton, Chandra, and NuSTAR

2020 ◽  
Vol 494 (4) ◽  
pp. 6012-6029 ◽  
Author(s):  
D J Walton ◽  
C Pinto ◽  
M Nowak ◽  
M Bachetti ◽  
R Sathyaprakash ◽  
...  
Keyword(s):  
Black Hole ◽  
Broad Band ◽  
High Energy ◽  
Accretion Disc ◽  
Continuum Emission ◽  
Spectral Variability ◽  
Temperature Behaviour ◽  
Temperature Relation ◽  
X Ray ◽  
Constant Area

ABSTRACT We present results from the major coordinated X-ray observing programme on the ULX NGC 1313 X-1 performed in 2017, combining XMM–Newton, Chandra, and NuSTAR, focusing on the evolution of the broad-band (∼0.3–30.0 keV) continuum emission. Clear and unusual spectral variability is observed, but this is markedly suppressed above ∼10–15 keV, qualitatively similar to the ULX Holmberg IX X-1. We model the multi-epoch data with two-component accretion disc models designed to approximate super-Eddington accretion, allowing for both a black hole and a neutron star accretor. With regards to the hotter disc component, the data trace out two distinct tracks in the luminosity–temperature plane, with larger emitting radii and lower temperatures seen at higher observed fluxes. Despite this apparent anticorrelation, each of these tracks individually shows a positive luminosity–temperature relation. Both are broadly consistent with L ∝ T4, as expected for blackbody emission with a constant area, and also with L ∝ T2, as may be expected for an advection-dominated disc around a black hole. We consider a variety of possibilities for this unusual behaviour. Scenarios in which the innermost flow is suddenly blocked from view by outer regions of the super-Eddington disc/wind can explain the luminosity–temperature behaviour, but are difficult to reconcile with the lack of strong variability at higher energies, assuming this emission arises from the most compact regions. Instead, we may be seeing evidence for further radial stratification of the accretion flow than is included in the simple models considered, with a combination of winds and advection resulting in the suppressed high-energy variability.

scholarly journals The Sax Mission For X-Ray Astronomy

1990 ◽  
Vol 123 ◽  
pp. 141-150 ◽  
Author(s):  
R.C. Butler ◽  
L. Scarsi
Keyword(s):  
Energy Band ◽  
Broad Band ◽  
Energy Spectra ◽  
X Ray ◽  
Joint Development ◽  
Space Agency ◽  
Italian Space Agency ◽  
Galactic Sources ◽  
Bright Source

AbstractThe satellite for X-ray astronomy SAX, to be launched at the end of 1993, is devoted to systematic, integrated and comprehensive, studies of galactic and extra-galactic sources in the energy band 0.1–200 keV, and is under joint development by the Italian Space Agency (ASI) and the Netherlands Agency for Aerospace programs (NIVR), with the participation of SRU/SRON and SSD/ESTEC. The basic scientific objectives can be summarized as follows:– Broad band spectroscopy (E/Δ E=12) from 0.1–10 keV with imaging resolution of 1 arcmin.– Continuum and line spectroscopy (E/Δ E=5–20) in the energy range 3–200 keV.– Variability studies of bright source energy spectra on timescales from milliseconds to days and months.– Systematic long term variability studies over the entire sky down to a source intensity of 1 mCrab.

scholarly journals OBSERVATIONS OF MICROQUASAR CANDIDATES WITH THE MAGIC TELESCOPE

2008 ◽  
Vol 17 (10) ◽  
pp. 1859-1866
Author(s):  
◽  
J. RICO
Keyword(s):  
Black Hole ◽  
Experimental Evidence ◽  
Energy Band ◽  
High Energy ◽  
Time Dependent ◽  
X Ray ◽  
Orbital Cycles ◽  
Very High Energy ◽  
Γ Ray ◽  
Very High

We report on the results from the observations in very high energy band (VHE, Eγ ≥ 100 GeV ) of the γ-ray binary LS I +61 303 and the black hole X-ray binary (BHXB) Cygnus X-1. LS I +61 303 was recently discovered at VHE by MAGIC1 and here we present the preliminary results from an extensive observation campaign, comprising 112 observation hours covering 4 orbital cycles, aiming at determining the time-dependent features of the VHE emission. Cygnus X-1 was observed for a total of 40 hours during 26 nights, spanning the period between June and November 2006. We report on the results of the searches for steady and variable γ-ray signals from Cygnus X-1, including the first experimental evidence for an intense flare, of duration between 1.5 and 24 hours.

Energy spectrometer on a diffractometer using a charge-coupled device X-ray detector

2006 ◽  
Vol 39 (5) ◽  
pp. 767-770
Author(s):  
Hiroshi Abe ◽  
Hiroyuki Saitoh ◽  
Hironori Nakao ◽  
Kazuki Ito ◽  
Ken-ichi Ohshima
Keyword(s):  
Pyrolytic Graphite ◽  
High Energy ◽  
Energy Spectra ◽  
Time Data ◽  
Charge Coupled Device ◽  
X Ray ◽  
High Energy Accelerator ◽  
X Ray Scattering ◽  
Energy Spectrometer ◽  
A Charge

A charge-coupled device (CCD) X-ray detector for inelastic X-ray scattering was installed at beamline BL-4C of the Photon Factory at the High Energy Accelerator Research Organization in Japan. A wavelength-dispersive X-ray spectrometer was mounted on a six-circle diffractometer. Energy spectra were obtained by the CCD X-ray detector and a curved highly oriented pyrolytic graphite analyser. By the combination of energy spectroscopy and diffraction, simultaneous real-time data acquisition of both the momentum and the energy transfer was performed.

scholarly journals Resonant inelastic X-ray scattering using a miniature dispersive Rowland refocusing spectrometer

2020 ◽  
Vol 27 (2) ◽  
pp. 446-454
Author(s):  
Alexander S. Ditter ◽  
William M. Holden ◽  
Samantha K. Cary ◽  
Veronika Mocko ◽  
Matthew J. Latimer ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Emission Spectroscopy ◽  
Spot Size ◽  
High Energy ◽  
Extensive Study ◽  
High Energy Resolution ◽  
X Ray ◽  
X Ray Scattering ◽  
Scientific Mission ◽  
Ray Scattering

X-ray absorption spectroscopy (XAS) beamlines worldwide are steadily increasing their emphasis on full photon-in/photon-out spectroscopies, such as resonant inelastic X-ray scattering (RIXS), resonant X-ray emission spectroscopy (RXES) and high energy resolution fluorescence detection XAS (HERFD-XAS). In such cases, each beamline must match the choice of emission spectrometer to the scientific mission of its users. Previous work has recently reported a miniature tender X-ray spectrometer using a dispersive Rowland refocusing (DRR) geometry that functions with high energy resolution even with a large X-ray spot size on the sample [Holden et al. (2017). Rev. Sci. Instrum. 88, 073904]. This instrument has been used in the laboratory in multiple studies of non-resonant X-ray emission spectroscopy using a conventional X-ray tube, though only for preliminary measurements at a low-intensity microfocus synchrotron beamline. This paper reports an extensive study of the performance of a miniature DRR spectrometer at an unfocused wiggler beamline, where the incident monochromatic flux allows for resonant studies which are impossible in the laboratory. The results support the broader use of the present design and also suggest that the DRR method with an unfocused beam could have important applications for materials with low radiation damage thresholds and that would not survive analysis on focused beamlines.

scholarly journals The December 2015 re-brightening of V404 Cygni

2018 ◽  
Vol 616 ◽  
pp. A129 ◽  
Author(s):  
J. J. E. Kajava ◽  
S. E. Motta ◽  
C. Sánchez-Fernández ◽  
E. Kuulkers
Keyword(s):  
Broad Band ◽  
High Energy ◽  
Accretion Disc ◽  
Band Spectrum ◽  
Hard Photon ◽  
Time Resolved ◽  
X Ray ◽  
Spectral Behaviour ◽  
Black Hole Binary ◽  
Spectral Cut

In December 2015 the black hole binary V404 Cyg underwent a secondary outburst after the main June 2015 event. We monitored this re-brightening with the INTEGRAL and Swift satellites, and in this paper we report the results of the time-resolved spectral analysis of these data. The December outburst shared several characteristics with the June event. The well-sampled INTEGRAL light curve shows up to ten Crab flares, which are separated by relatively weak non-flaring emission phases when compared to the June outburst. The spectra are nicely described by absorbed Comptonization models, with hard photon indices, Γ ≲ 2, and significant detections of a high-energy cut-off only during the bright flares. This is in contrast to the June outburst, where the Comptonization models gave electron temperatures mostly in the 30–50 keV range, while some spectra were soft (Γ ~ 2.5) without signs of any spectral cut-off. Similarly to the June outburst, we see clear signs of a variable local absorber in the soft energy band covered by Swift/XRT and INTEGRAL/JEM-X, which causes rapid spectral variations observed during the flares. During one flare, both Swift and INTEGRAL captured V404 Cyg in a state where the absorber was nearly Compton thick, N H ≈ 1024 cm−2, and the broad-band spectrum was similar to obscured AGN spectra, as seen during the X-ray plateaus in the June outburst. We conclude that the spectral behaviour of V404 Cyg during the December outburst was analogous with the first few days of the June outburst, both having hard X-ray flares that were intermittently influenced by obscuration due to nearly Compton-thick outflows launched from the accretion disc.

scholarly journals New measurements of the cyclotron line energy in Cen X-3

2020 ◽  
Vol 500 (3) ◽  
pp. 3454-3461
Author(s):  
Gunjan Tomar ◽  
Pragati Pradhan ◽  
Biswajit Paul
Keyword(s):  
Broad Band ◽  
Resonant Scattering ◽  
High Energy ◽  
Emission Lines ◽  
Power Law Model ◽  
Pulse Profile ◽  
Line Energy ◽  
X Ray ◽  
Cyclotron Absorption ◽  
Cyclotron Line

ABSTRACT We report results from the analysis of data from two observations of the accreting binary X-ray pulsar Cen X-3 carried out with the broad-band X-ray observatories Suzaku and NuSTAR. The pulse profile is dominated by a broad single peak and show some energy dependence with two additional weak pulse peaks at energies below 15 and 25 keV, respectively. The broad-band X-ray spectrum for 0.8–60.0 keV for Suzaku  and 3.0–60.0 keV for NuSTAR is fitted well with high-energy cut-off power-law model along with soft-excess, multiple iron emission lines and a cyclotron absorption. The cyclotron line energy is found to be $30.29^{+0.68}_{-0.61}$ and $29.22^{+0.28}_{-0.27}$ keV, respectively, in the Suzaku  and NuSTAR  spectra. We make a comparison of these two measurements with four previous measurements of Cyclotron Resonant Scattering Feature (CRSF) in Cen X-3  obtained with Ginga, BeppoSAX,  and RXTE. We find no evidence for a dependence of the CRSF on luminosity. Except for one CRSF measurement with BeppoSAX , the remaining measurements are consistent with a CRSF energy in the range of 29.5–30.0 keV over a luminosity range of 1.1–5.4 × 1037 erg s−1 different from several other sources that show considerable CRSF variation in the same luminosity range.

scholarly journals Energy distribution of relativistic electrons in the kiloparsec scale jet of M 87 with Chandra

2018 ◽  
Vol 612 ◽  
pp. A106 ◽  
Author(s):  
Xiao-Na Sun ◽  
Rui-Zhi Yang ◽  
Frank M. Rieger ◽  
Ruo-Yu Liu ◽  
Felix Aharonian
Keyword(s):  
Power Law ◽  
Broad Band ◽  
High Energy ◽  
Spectral Energy ◽  
Relativistic Electrons ◽  
Complex Situation ◽  
Satisfactory Description ◽  
X Ray ◽  
General Decline ◽  
Photon Index

The X-ray emission from the jets in active galactic nuclei (AGN) carries important information on the distributions of relativistic electrons and magnetic fields on large scales. We reanalysed archival Chandra observations on the jet of M 87 from 2000 to 2016 with a total exposure of 1460 kiloseconds to explore the X-ray emission characteristics along the jet. We investigated the variability behaviours of the nucleus and the inner jet component HST-1, and confirm indications for day-scale X-ray variability in the nucleus contemporaneous to the 2010 high TeV γ-ray state. HST-1 shows a general decline in X-ray flux over the last few years consistent with its synchrotron interpretation. We extracted the X-ray spectra for the nucleus and all knots in the jet, showing that they are compatible with a single power law within the X-ray band. There are indications that the resultant X-ray photon index exhibit a trend, with slight but significant index variations ranging from ≃ 2.2 (e.g. in knot D) to ≃ 2.4−2.6 (in the outer knots F, A, and B). When viewed in a multiwavelength context, a more complex situation can be seen. Fitting the radio to X-ray spectral energy distributions (SEDs) assuming a synchrotron origin, we show that a broken power-law electron spectrum with break energy Eb around 1 (300 μG/B)1/2 TeV allows a satisfactory description of the multiband SEDs for most of the knots. However, in the case of knots B, C, and D we find indications that an additional high-energy component is needed to adequately reproduce the broad-band SEDs. We discuss the implications and suggest that a stratified jet model may account for the differences.

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