Low Energy X-Ray Transmission Grating Spectrometer For AXAF

Brinkman, A. C.; Rooijen, J. J. van; Bleeker, J. A. M.; Dijkstra, J. H.; Heise, J.; Korte, P. A. J. de; Mewe, R.; Paerels, F.

doi:10.1117/12.966587

Cited by 13 publications

(8 citation statements)

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“…A final note on the response functions and the robustness of the SDC method. The MUSE passbands are well known and have been observed before, either with EIS (284 Å and to some extent 171 Å; Brown et al 2008), Chandra (108 Å;Weisskopf et al 2002;Brinkman et al 1987;Testa et al 2012b), and sounding rockets (171 Å; Wang et al 2010). There is the possibility that some weak unknown lines are present in MUSE data.…”

Section: B1 Active Regionmentioning

confidence: 74%

The Multi-slit Approach to Coronal Spectroscopy with the Multi-slit Solar Explorer (MUSE)

Pontieu¹,

Martínez-Sykora²,

Testa³

et al. 2019

ApJ

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The Multi-slit Solar Explorer (MUSE) is a proposed mission aimed at understanding the physical mechanisms driving the heating of the solar corona and the eruptions that are at the foundation of space weather. MUSE contains two instruments, a multi-slit EUV spectrograph and a context imager. It will simultaneously obtain EUV spectra (along 37 slits) and context images with the highest resolution in space (0.33-0.4 ) De Pontieu et al. straightforward, as a simultaneous measurement of I(x, y, λ) is always achieved. Detectors for hard X-rays (HXR) provide an energy resolution of a fraction of a keV (Furukawa et al. 2019; Athiray et al. 2017), and a useful resolving power for gamma rays and HXR bremsstrahlung continua, applicable to the very hottest components of the corona, but unfortunately, not for the majority of coronal features that emit EUV. Furthermore, the spatial resolution of state-of-the-art X-ray telescopes (Buitrago-Casas et al. 2017; Chan et al. 2018) is not sufficient to resolve the cross-sectional profiles of bright coronal loops, or their footpoints, where the majority of HXR emission is produced. For soft X-rays (SXR), Bandler et al. (2019) recently demonstrated transition-edge-sensor-based microcalorimeter arrays that provide an energy resolution of 2 eV over the energy range 0.2-7 keV, and thus a resolving power of 3, 500 at 7 keV, but dropping to 100 at ∼ 200eV (∼ 60Å). The count rates for such microcalorimeter systems are limited, and the achievable dynamic range, currently, compromises the utility of such systems for solar observations. Options 2 and 3 can be implemented in a variety of ways, some of which require a sequence of multiple measurements to obtain a single "snapshot" of I(x, y, λ). Analysis of such data is straightforward when the time scales of the process under study are longer than the cycle time of the sequence. Narrow passband filters to implement option 2 are employed at visible, infrared (IR) and radio-frequency (RF) wavelengths, including the measurement of I for multiple polarization states in order to perform spectropolarimetric inversions using visible and near-infrared (NIR) line emission (e.g., Scharmer et al. 2008), and microwave and RF observations of gyroresonance emission, which in combination with high resolution EUV observations can provide valuable diagnostics of the 3D structure of the coronal magnetic field (e.g., Brosius et al. 2002) and electron beams generated in flares and jets (e.g. Chen et al. 2013). Owing ultimately to the low reflectance and transmittance of materials for EUV wavelengths, the achievable resolving power of EUV multilayer coatings for option 2 is only around 10 to 30. A spectrograph, option 3, therefore provides the best resolving power in the EUV.In a traditional imaging spectrograph, light passes through a single entrance slit and is dispersed and re-imaged onto the focal plane. This preserves spatial information in the direction perpendicular

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Section: B1 Active Regionmentioning

confidence: 74%

The Multi-slit Approach to Coronal Spectroscopy with the Multi-slit Solar Explorer (MUSE)

Pontieu¹,

Martínez-Sykora²,

Testa³

et al. 2019

ApJ

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“…Using a simple analysis taking into account dilution of the photospheric UV field and a 1/r 2 falloff in wind density, Miller et al (2002) derived formation regions for the dominant He-like ions Mg XI, Ne IX, and O VII extending just above the stellar photosphere to 3-10 times the photospheric radius. An analysis of a 100 ks Chandra Low Energy Transmission Grating Spectrometer (LETGS; Brinkman et al 1987) + High Resolution Camera observation from 2007 November 09 by Raassen & Pollock (2013) also showed that the Mg XI, Ne IX, and O VII emission regions extend from 2-10 stellar radius, and showed that the longer wavelength ions like N VI and C V form at substantially greater distances from the star (50-75 times the stellar radius), and that the spectrum could be modeled by a three-temperature plasma in collisional ionization equilibrium with temperatures of 0.1, 0.2, and 0.6 keV.…”

Section: Previous X-ray Observationsmentioning

confidence: 99%

A COORDINATED X-RAY AND OPTICAL CAMPAIGN OF THE NEAREST MASSIVE ECLIPSING BINARY,δORIONIS Aa. I. OVERVIEW OF THE X-RAY SPECTRUM

Corcoran

Nichols

Pablo

et al. 2015

ApJ

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We present an overview of four deep phase-constrained Chandra HETGS X-ray observations of δ Ori A. Delta Ori A is actually a triple system which includes the nearest massive eclipsing spectroscopic binary, δ Ori Aa, the only such object that can be observed with little phasesmearing with the Chandra gratings. Since the fainter star, δ Ori Aa2, has a much lower X-ray luminosity than the brighter primary (δ Ori Aa1), δ Ori Aa provides a unique system with which to test the spatial distribution of the X-ray emitting gas around δ Ori Aa1 via occultation by the photosphere of, and wind cavity around, the X-ray dark secondary. Here we discuss the X-ray spectrum and X-ray line profiles for the combined observation, having an exposure time of nearly 500 ks and covering nearly the entire binary orbit. The companion papers discuss the X-ray variability seen in the Chandra spectra, present new space-based photometry and ground-based radial velocities obtained simultaneous with the X-ray data to better constrain the system parameters, and model the effects of X-rays on the optical and UV spectra. We find that the X-ray emission is dominated by embedded wind shock emission from star Aa1, with little contribution from the tertiary star Ab or the shocked gas produced by the collision of the wind of Aa1 against the surface of Aa2. We find a similar temperature distribution to previous X-ray spectrum analyses. We also show that the line half-widths are about 0.3 − 0.5 times the terminal velocity of the wind of star Aa1. We find a strong anti-correlation between line widths and the line excitation energy, which suggests that longer-wavelength, lower-temperature lines form farther out in the wind. Our analysis also indicates that the ratio of the intensities of the strong and weak lines of Fe XVII and Ne X are inconsistent with model predictions, which may be an effect of resonance scattering.

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“…More in depth discussions of the Chandra mission, spacecraft, other instruments and subsystems are presented elsewhere. 6,7,8,9,10,11…”

Section: Chandra X-ray Observatory's Focal Plane Instrumentsmentioning

confidence: 99%

Monitoring the Health and Safety of the ACIS Instrument On-Board the Chandra X-ray Observatory

Virani

Ford

DePasquale

et al. 2002

Observatory Operations to Optimize Scientific Return III

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The Chandra X-ray Observatory (CXO), NASA's latest "Great Observatory", was launched on July 23, 1999 and reached its final orbit on August 7, 1999. The CXO is in a highly elliptical orbit, approximately 140,000 km x 10,000 km, and has a period of approximately 63.5 hours (≈ 2.65 days). Communication with the CXO nominally consists of 1-hour contacts spaced 8-hours apart. Thus, once a communication link has been established, it is very important that the health and safety status of the scientific instruments as well as the Observatory itself be determined as quickly as possible.In this paper, we focus exclusively on the automated health and safety monitoring scripts developed for the Advanced CCD Imaging Spectrometer (ACIS) to use during those 1-hour contacts. ACIS is one of the two focal plane instruments on-board the CXO. We present an overview of the real-time ACIS Engineering Data Web Page and the alert schemes developed for monitoring the instrument status during each communication contact. A suite of HTML and PERL scripts monitors the instrument hardware house-keeping electronics (i.e., voltages and currents) and temperatures during each contact. If a particular instrument component is performing either above or below pre-established operating parameters, a sequence of email and alert pages are spawned to the Science Operations Team of the Chandra X-ray Observatory Center so that the anomaly can be quickly investigated and corrective actions taken if necessary. We also briefly discuss the tools used to monitor the real-time science telemetry reported by the ACIS flight software.The authors acknowledge support for this research from NASA contract NAS8-39073.The CXO's operational orbit has an apogee of approximately 140,000 km and a perigee of nearly 10,000 km, with a 28.5 • initial inclination. The CXO's highly elliptical orbit, with an orbital period of approximately 2.65 days, results in high observing efficiency. Moreover, the fraction of the sky occulted by the Earth is small over most of the orbital period, as is the fraction of time when the detector backgrounds are high as the CXO dips into the Earth's radiation belts. Consequently, approximately 85% of Chandra's orbit is available for observing. In fact, uninterrupted observations lasting as long as 2.3 days are possible. 1The CXO carries two focal plane science instruments: the High Resolution Camera (HRC) and the Advanced CCD Imaging Spectrometer (ACIS). The Observatory also possesses two objective transmission gratings: a Low Energy Transmission Grating (LETG) that is primarily used with the HRC, and the High Energy TransmissionThe High Resolution Camera, HRC, is a microchannel plate (MCP) instrument. It is comprised of two detector elements, a ∼ 100 mm square optimized for imaging (HRC-I) and a ∼ 20 x 300 mm rectangular device optimized for the Low Energy Transmission Grating (LETG) Spectrometer readout (HRC-S).The HRC has the highest spatial resolution imaging on Chandra -≤ 0.5 arcsec (FWHM) -matching the High Resolution Mirror Assembly (HRMA) p...

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Low Energy X-Ray Transmission Grating Spectrometer For AXAF

Cited by 13 publications

References 0 publications

The Multi-slit Approach to Coronal Spectroscopy with the Multi-slit Solar Explorer (MUSE)

The Multi-slit Approach to Coronal Spectroscopy with the Multi-slit Solar Explorer (MUSE)

A COORDINATED X-RAY AND OPTICAL CAMPAIGN OF THE NEAREST MASSIVE ECLIPSING BINARY,δORIONIS Aa. I. OVERVIEW OF THE X-RAY SPECTRUM

Monitoring the Health and Safety of the ACIS Instrument On-Board the Chandra X-ray Observatory

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