scholarly journals High-resolution X-ray spectroscopy of astrophysical plasmas with X-ray microcalorimeters

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Yuichiro Ezoe ◽  
Takaya Ohashi ◽  
Kazuhisa Mitsuda
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
High Sensitivity ◽  
Resolving Power ◽  
High Spectral Resolution ◽  
High Resolution Spectroscopy ◽  
Astrophysical Plasmas ◽  
X Ray ◽  
New Findings ◽  
Perseus Cluster

AbstractHigh spectral resolution with a resolving power, $$E/\Delta E \gtrsim 1000$$ E / Δ E ≳ 1000 at 6 keV, is now available in X-ray astronomy. X-ray observations are particularly effective for plasma studies since major atomic transitions appear as spectral features in the X-ray band. High-resolution spectroscopy enables us to probe a wide variety of astrophysical plasmas, which are not obtainable from ground experiments, regarding their temperature, density, magnetic field, gravity, and velocity. In this review, we describe what are the X-ray emitting plasmas in the Universe, along with basic plasma diagnostics, and depict historical development of the techniques used for the X-ray spectroscopy. We outline the X-ray microcalorimeter instrument, soft X-ray spectrometer (SXS), onboard the ASTRO-H satellite. Despite the short lifetime of the satellite in orbit for about a month, observations with the SXS have shown the remarkable power of high-resolution spectroscopy in X-ray astronomy. Observed spectrum of the hot plasma in the core region of the Perseus cluster showed He-like Fe K-line to be clearly resolved into resonance, forbidden and intercombination lines for the first time. The line width indicates that the turbulent pressure amounts to only 4% of the thermal pressure of the plasma. We also describe new findings and constraints obtained from the superb spectrum of the Perseus cluster, which all indicate a great potential of X-ray spectroscopy. The recovery of the spectroscopy science of ASTRO-H is aimed at with XRISM, a Japanese mission planned for launch in early 2020s. In further future, Athena will expand the rich science with its high sensitivity and spectral resolution in early 2030s.

scholarly journals Goals for the Application of High-Resolution X-ray Spectroscopy to the Diagnosis of Stellar Coronal Plasmas

1990 ◽  
Vol 115 ◽  
pp. 94-109 ◽  
Author(s):  
Jeffrey L. Linsky
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
Transient Flow ◽  
Emission Measure ◽  
Active Regions ◽  
High Sensitivity ◽  
High Spectral Resolution ◽  
Spectral Features ◽  
Signal To Noise ◽  
X Ray

AbstractI provide examples of how high-resolution x-ray spectra may be used to determine the temperature and emission measure distributions, electron densities, steady and transient flow velocities, and location of active regions in stellar coronae. For each type of measurement I estimate the minimum spectral resolution required to resolve the most useful spectral features. In general, high sensitivity is required to obtain sufficient signal-to-noise to exploit the high spectral resolution. Although difficult, each measurement should be achievable with the instrumentation proposed for AXAF.

scholarly journals Multilayer Mirror Based High-Resolution Solar Soft X-Ray Spectrometer

2021 ◽  
Vol 8 ◽  
Author(s):  
S. S. Panini ◽  
S. Narendranath ◽  
P. Sreekumar ◽  
K. Sankarasubramanian
Keyword(s):  
High Resolution ◽  
Spectral Range ◽  
Spectral Resolution ◽  
High Spectral Resolution ◽  
High Resolution Spectroscopy ◽  
Time Variability ◽  
Type I ◽  
The Sun ◽  
X Rays ◽  
X Ray

Soft X-ray spectroscopy of the Sun is an important tool to understand the coronal dynamics and composition. The solar coronal X-ray spectrum below 1 keV is the least explored with high-resolution spectroscopy. Recent observations with Hinode XRT using coarse spectroscopy along with high-resolution imaging have shown that abundances in the coronae have variability associated with structures on the Sun. Disk averaged abundances with better spectral resolution spectrometers show time variability associated with flares. Both spatial and temporal variabilities seem to be related to changes in the magnetic field topology. Understanding such short term variabilities is necessary to model the underlying dynamics and mixing of material between different layers of the Sun. A Sensitive high-resolution spectrometer that covers the range in plasma temperatures and emission line complexes would uniquely reveal the entire evolution of flares. We are investigating a design of a multi-layer mirror-based X-ray spectrograph in the spectral range from 0.5 to 7 keV. The instrument operates in four asynchronous spectral channels operating one at a time. The multi-layer mirror placed at the focus of a Wolter type I telescope reflects a narrow band X-rays to the CCD which is placed at Nasmyth defocus. Converging X-rays from the front end optics helps to increase the spectral range of each channel while preserving the spectral resolution. This design is estimated to achieve a spectral resolution of 20 eV in the spectral range of 0.5–7 keV. With such high spectral resolution, we can resolve individual spectral features e.g., 6.7 keV Fe complex which can be used to diagnose high-temperature transient plasma during flares. The instrument design estimated performance and the science capabilities of this instrument will be discussed in detail in the paper.

scholarly journals Wide Swath and High Resolution Airborne HyperSpectral Imaging System and Flight Validation

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1667 ◽  
Author(s):  
Dong Zhang ◽  
Liyin Yuan ◽  
Shengwei Wang ◽  
Hongxuan Yu ◽  
Changxing Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Spectral Resolution ◽  
High Efficiency ◽  
High Spatial Resolution ◽  
Imaging System ◽  
High Sensitivity ◽  
Field Of View ◽  
High Spectral Resolution ◽  
Wide Swath

Wide Swath and High Resolution Airborne Pushbroom Hyperspectral Imager (WiSHiRaPHI) is the new-generation airborne hyperspectral imager instrument of China, aimed at acquiring accurate spectral curve of target on the ground with both high spatial resolution and high spectral resolution. The spectral sampling interval of WiSHiRaPHI is 2.4 nm and the spectral resolution is 3.5 nm (FWHM), integrating 256 channels coving from 400 nm to 1000 nm. The instrument has a 40-degree field of view (FOV), 0.125 mrad instantaneous field of view (IFOV) and can work in high spectral resolution mode, high spatial resolution mode and high sensitivity mode for different applications, which can adapt to the Velocity to Height Ratio (VHR) lower than 0.04. The integration has been finished, and several airborne flight validation experiments have been conducted. The results showed the system’s excellent performance and high efficiency.

Star And Planet’s Characterisation Through High Spectral Resolution

2020 ◽  
Author(s):  
Maria Chiara Maimone ◽  
Andrea Chiavassa ◽  
Jeremy Leconte ◽  
Matteo Brogi
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
Molecular Species ◽  
Climate Model ◽  
Global Climate Model ◽  
Spectral Lines ◽  
High Spectral Resolution ◽  
High Resolution Spectroscopy ◽  
Stellar Disk ◽  
Precise Knowledge

<p>The study of exoplanets atmospheres is one of the most intriguing challenges in exoplanet field nowadays and the High Resolution Spectroscopy (HRS) has recently emerged as one of the leading methods for detecting atomic and molecular species in their atmospheres. In terms of numbers, if we define the resolution power R,<span class="Apple-converted-space">  </span>where λ is the wavelength and Δλ is the spectral resolution:</p> <p><span class="Apple-converted-space">     R= λ/Δλ</span></p> <p>then, “High Resolution Spectroscopy” means R > 50 000.</p> <p>Nevertheless extraordinary results have been achieved (Birkby, 2018), High Resolution Spectroscopy alone is not enough. 1D models of the host star have been coupled to HRS observations, but they do not reproduce the complexity of stellar convection mechanism (Chiavassa & Brogi, 2019). On the contrary,<span class="Apple-converted-space">  </span>3D Radiative Hydrodynamical simulations (3D RHS) take it into account intrinsically, allowing us to correctly reproduce asymmetric and blue-shifted spectral lines due to the granulation pattern of the stellar disk, which is a very important source of uncertainties at this resolution level (Chiavassa et al. 2017).</p> <p>However, numerical simulations have been computed independently for star and planet so far, while the acquired spectra are an entanglement of both the signals. In particular, some molecular species (e.g, CO) form in the same region of the spectrum, thus planetary and stellar spectral lines are completely mixed and overlapped.<span class="Apple-converted-space"> </span></p> <p>Therefore, a next step forward is needed: computing stellar and planetary models <em>together.</em></p> <p>With our work, we aim at upgrading the already-in-place 3D radiative transfer code Optim3D (Chiavassa et al. 2009) —largely used for stellar purposes so far — to taking into account also the exoplanetary contribution.<span class="Apple-converted-space"> </span>We propose to use simultaneously 3D RHS, performed for stars, and the innovative Global Climate Model (GCM), drawn up for exoplanets, in order to generate unprecedented precise synthetic spectra. As a springboard to test the code, we are carrying out the analysis of CO and H2O molecules on the well-know benchmark HD189733. Indeed, to disentangle those star’s and its companion’s signals due to the same molecules is one of the most challenging problems. In the end, we will be able to compute a complete dynamic characterisation: on one side, a precise knowledge of the stellar dynamic (i.e. convection-related surface structures) would allow to extract unequivocally the planetary signal; on the other one, a well-modelled dynamic of the planet (i.e. depth, shape, and position of spectral lines) would provide us with considerable information about the planetary atmospheric circulation.</p>

On obtaining high spectral resolution in extreme ultraviolet/soft X-ray monochromators operating off-plane diffraction in a divergent incident beam

2020 ◽  
Vol 27 (6) ◽  
pp. 1499-1509
Author(s):  
Werner Jark
Keyword(s):  
Spectral Resolution ◽  
Extreme Ultraviolet ◽  
Specular Reflection ◽  
Incident Beam ◽  
Diffraction Order ◽  
Source Size ◽  
Resolving Power ◽  
High Spectral Resolution ◽  
Radiation Beam ◽  
X Ray

When the trajectory of an incident beam is oriented parallel to the grooves of a periodic grating structure the radiation beam is diffracted off-plane orthogonal to the plane of incidence. The diffraction efficiency in this condition is very high and in a grating with a sawtooth profile it can approach the reflection coefficient for a simple mirror, when the diffraction order of interest follows the direction for specular reflection at the flat part of the steps. When this concept is used in a plane grating in a monochromator for synchrotron radiation sources, the incident beam is almost always collimated in order to minimize any deterioration of the beam properties due to aberrations, which will be introduced in the diffraction process when an uncollimated beam is used. These aberrations are very severe when the groove density is constant. It will be shown that the effect of these aberrations can be corrected after the diffraction by the use of astigmatic focusing. The latter can be provided by a crossed mirror pair with different focal lengths in the corresponding orthogonal directions. Then a monochromator based on this concept can provide source size limited spectral resolution in an uncollimated incident beam. This is identical to the spectral resolution that can be provided by the same grating when operated at the same position in a collimated incident beam. The source size limited spectral resolution in this case corresponds to a high spectral resolving power of better than ΔE/E = 10 000 for photon energies around 300 eV in the soft X-ray range.

Thermal Detectors for X-ray Astronomy

1990 ◽  
Vol 115 ◽  
pp. 346-356
Author(s):  
Stephen S. Holt
Keyword(s):  
High Resolution ◽  
Quantum Efficiency ◽  
Spectral Resolution ◽  
High Spectral Resolution ◽  
X Ray ◽  
Thermal Detectors ◽  
The Sacrifice

AbstractSpectroscopy is traditionally characterized by the sacrifice of quantum efficiency for high spectral resolution. Since X-ray astronomy is a photon-limited discipline, the choice between high resolution for very few sources versus much lower resolution for many more has not always been an easy one. The development of new thermal detectors offers the opportunity to “have one’s cake and eat it, too.”

scholarly journals THE ASTRO-H MISSION

2013 ◽  
Vol 53 (A) ◽  
pp. 803-806
Author(s):  
Yoshitomo Maeda ◽  
Tadayuki Takahashi ◽  
Kazuhisa Mitsuda ◽  
Richard Kelley
Keyword(s):  
Spectral Resolution ◽  
High Sensitivity ◽  
High Energy ◽  
The Other ◽  
High Spectral Resolution ◽  
High Energy Astrophysics ◽  
Extended Source ◽  
X Ray ◽  
Imaging Capability ◽  
Wide Energy

A review of the Astro-H mission is presented here on behalf of the Astro-H collaboration. The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). One of the main uniquenesses of the ASTRO-H satellite is the high sensitivity and imaging capability of the wide energy band from 0.3 keV to 600 keV. The coverage is achieved by combining the four instruments of the SXS, SXI, HXI, and SGD. The other main uniqueness is a spectroscopic capability not only for a point-like source but also for an extended source with high spectral resolution of Δ<em>E</em>~4÷7eV of SXS. Using the unique powers of these instruments, ASTRO-H will address unresolved issues in high-energy astrophysics.

scholarly journals The Constellation X-ray Mission

2000 ◽  
Vol 195 ◽  
pp. 61-68
Author(s):  
N. E. White ◽  
H. Tananbaum
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
Energy Band ◽  
High Spectral Resolution ◽  
X Ray ◽  
Increased Sensitivity ◽  
Similar Factor ◽  
Area X ◽  
The Universe ◽  
Broad Energy

The Constellation-X mission is a large collecting-area X-ray facility emphasizing observations at high spectral resolution (E/ΔE ~ 300–3000) while covering a broad energy band (0.25–40 keV). By increasing the telescope aperture and utilizing efficient spectrometers, the mission will achieve a factor of 100 increased sensitivity over current high-resolution X-ray spectroscopy missions. The use of focusing optics across the 10–40 keV band will provide a similar factor of 100 increased sensitivity in this band. When observations commence in ~ 2008, Constellation-X will address many pressing questions concerning the extremes of gravity and the evolution of the Universe.

High spectral resolution, high sensitivity microwave and associated hard X-ray bursts

1993 ◽  
Vol 13 (9) ◽  
pp. 191-194 ◽  
Author(s):  
H.S. Sawant ◽  
J.R. Cecatto ◽  
B.R. Dennis ◽  
D.E. Gary ◽  
G.J. Hurford
Keyword(s):  
Spectral Resolution ◽  
High Sensitivity ◽  
High Spectral Resolution ◽  
X Ray

scholarly journals Hitomi X-ray Astronomy Satellite: Power of High-Resolution Spectroscopy

2016 ◽  
Vol 11 (S322) ◽  
pp. 197-203
Author(s):  
Hirokazu Odaka ◽  
Keyword(s):  
High Resolution ◽  
Velocity Dispersion ◽  
Galactic Center ◽  
Emission Lines ◽  
High Resolution Spectroscopy ◽  
Line Of Sight ◽  
Sudden Loss ◽  
X Ray ◽  
Turbulent Pressure ◽  
Perseus Cluster

AbstractHitomi (ASTRO-H) is an X-ray observatory developed by an international collaboration led by JAXA. An X-ray microcalorimeter onboard this satellite has opened a new window of high-resolution spectroscopy with an unprecedented energy resolution of 5 eV (FWHM) at 6 keV. The spacecraft was launched on February 17, 2016 from Tanegashima Island, Japan, and we completed initial operations including deployment of the hard X-ray imagers on the extensible optical bench. All scientific instruments had successfully worked until the sudden loss of the mission on March 26. We have obtained a spectrum showing fully resolved emission lines through the first-light observation of the Perseus Cluster. The line-of-sight velocity dispersion of 164 ± 10 km s−1 reveals the quiescent environment of intracluster medium at the cluster core, implying that measured cluster mass requires little correction for the turbulent pressure. We also discuss observations to the Galactic Center which could be performed with Hitomi.

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