&lt;title&gt;Description and performance of the low-energy transmission grating spectrometer on board Chandra&lt;/title&gt;

Brinkman, A. C.; Gunsing, Theo; Kaastra, J. S.; Meer, Rob van der; Mewe, R.; Paerels, F.; Raassen, Ton; Rooijen, J. van; Braeuninger, Heinrich W.; Burwitz, V.; Hartner, Gisela; Kettenring, G.; Predehl, P.; Drake, J. J.; Johnson, C. Olivia; Kenter, A.; Kraft, Ralph; Murray, Stephen S.; Ratzlaff, Peter W.; Wargelin, Bradford J.

doi:10.1117/12.391599

Cited by 55 publications

(22 citation statements)

References 2 publications

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“…The calibration of the LETG+HRC-S at long wavelengths is based, in part, on Sirius B and HZ43 A (Brinkman et al 2000;Pease et al 2000), with a certain preference given to Sirius B because of its better defined log g (Barstow et al 2005;Holberg et al 1998). The drawback is the lack of a useful signal from Sirius B at λ < 60 Å, while HZ43 A can be detected at least down to λ = 44 Å.…”

Section: Chandra Letg+hrc Spectramentioning

confidence: 99%

“…Bohlin et al 2001) and have played a decisive role in the calibration of satellite instruments in all spectral regimes from the optical to the extreme ultraviolet and soft X-rays. The FOS and STIS on the Hubble Space Telescope (Bohlin 2000), the Extreme Ultraviolet Explorer (EUVE) (Boyd et al 1994), and the Low Energy Transmission Grating Spectrometer on board Chandra (LETG+HRC-S) with the High Resolution Camera as detector (Brinkman et al 2000;Pease et al 2000) are prominent…”

Section: Introductionmentioning

confidence: 99%

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Establishing HZ43 A, Sirius B, and RX J185635-3754 as soft X-ray standards: a cross-calibration between the Chandra LETG+HRC-S, the EUVE spectrometer, and the ROSAT PSPC

Beuermann¹,

Burwitz

Rauch³

2006

A&A

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Context. The absolute calibration of space-borne instruments in the soft X-ray regime rests strongly on model spectra of hot white dwarfs. Aims. We analyze the Chandra LETG+HRC observations of the white dwarfs HZ43 A and Sirius B and of the neutron star RX J185635−3754 with the aim of resolving current uncertainties in the soft X-ray spectral fluxes and photospheric parameters of the three stars. We apply the derived photon spectra to a cross-calibration of the LETG+HRC-S with the short-wavelength EUVE spectrometer and the ROSAT PSPC. Methods. We tie HZ43 A to the flux of RX J1856 in the 44−48 Å range and perform a simultaneous least squares fit to the LETG+HRC spectra of the three stars. This allows us to determine an internally consistent set of spectral energy distributions and an empirically derived wavelength-dependent correction to the LETG+HRC-S effective area. We employ NLTE model atmospheres calculated with TMAP for the white dwarfs and a two-blackbody model for RX J1856, tied to the respective optical fluxes. Results. The two-blackbody model for RX J1856 features a hot spot on a cooler star and yields kT spot = 62.8 ± 0.4 eV and kT star = 32.3 ± 0.7 eV with a stellar angular radius as seen from infinity of 0.1371 ± 0.0010 km pc −1 . For HZ43 A, our fit yields T eff = 51 126 ± 660 K and log g = 7.90 ± 0.080 (cgs) with anti-correlated errors (1-σ) which include not only the statistical but also the systematic uncertainties of the fit. HZ43AB displays a previously detected bremsstrahlung component with a temperature kT 0.6 keV. For Sirius B, we find T eff = 24 923 ± 115 K for fixed log g = 8.6. The calibration of the short-wavelength EUVE spectrometer differs from that of the LETG+HRC-S by 15 ± 7%. The ROSAT PSPC is found to be correctly calibrated within a few percent and reports of a major miscalibration are unfounded. Conclusions. We have obtained improved parameters for RX J185635−3754, HZ43 A, and Sirius B which fit the observations from the optical to the soft X-ray regime. Our approach allows us to quote their absolute spectral fluxes at selected wavelengths which may aid the calibration of other space-borne instruments.

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Section: Chandra Letg+hrc Spectramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Establishing HZ43 A, Sirius B, and RX J185635-3754 as soft X-ray standards: a cross-calibration between the Chandra LETG+HRC-S, the EUVE spectrometer, and the ROSAT PSPC

Beuermann¹,

Burwitz

Rauch³

2006

A&A

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“…The gratings on board NASA's Chandra satellite (HETGS/LETGS, e.g. Brinkman et al 2000 andCanizares et al 2005) have the highest spectral resolution available in the X-ray band, but their effective area is smaller than that of RGS in the soft X-ray band where most ULX wind features are shown and where the flux is highest. HETGS and LETGS are clearly optimal to distinguish spectral features in the brightest objects, whilst the RGS has unique capabilities to detect lines in weak objects, which means that the continuation of the XMM-Newton and Chandra missions is crucial to study the ULXs and ULSs in detail.…”

Section: Xmm-newton In the Next Decadementioning

confidence: 99%

From ultraluminous X-ray sources to ultraluminous supersoft sources: NGC 55 ULX, the missing link

Pinto

Alston

Soria

et al. 2017

Monthly Notices of the Royal Astronomical Society

130

188

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In recent work with high-resolution grating spectrometers (RGS) aboard XMM-Newton Pinto et al. (2016) have discovered that two bright and archetypal ultraluminous X-ray sources (ULXs) have strong relativistic winds in agreement with theoretical predictions of high accretion rates. It has been proposed that such winds can become optically thick enough to block and reprocess the disk X-ray photons almost entirely, making the source appear as a soft thermal emitter or ultraluminous supersoft Xray source (ULS). To test this hypothesis we have studied a ULX where the wind is strong enough to cause significant absorption of the hard X-ray continuum: NGC 55 ULX. The RGS spectrum of NGC 55 ULX shows a wealth of emission and absorption lines blueshifted by significant fractions of the light speed (0.01 − 0.20)c indicating the presence of a powerful wind. The wind has a complex dynamical structure with the ionization state increasing with the outflow velocity, which may indicate launching from different regions of the accretion disk. The comparison with other ULXs such as NGC 1313 X-1 and NGC 5408 X-1 suggests that NGC 55 ULX is being observed at higher inclination. The wind partly absorbs the source flux above 1 keV, generating a spectral drop similar to that observed in ULSs. The softening of the spectrum at lower (∼ Eddington) luminosities and the detection of a soft lag agree with the scenario of wind clumps crossing the line of sight, partly absorbing and reprocessing the hard X-rays from the innermost region.

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“…Chandra LETGS This instrument was designed and built by SRON and MPE Garching (Brinkman et al 2000). It comprises grating facets of gold with 1000 lines/mm, supported with a pitch of 25 µm/2 mm.…”

Section: Spectrographs On Chandra and On Xmm-newtonmentioning

confidence: 99%

Spectroscopy in Utrecht: A Brief History

Verbunt

Bleeker

2010

Space Sci Rev

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In the first half of the 20th century, Leonard Ornstein turned the Physics Laboratory of Utrecht University into a center for testing the nascent quantum mechanics through accurate measurements of line intensities in flame spectra. The microphotometer of instrument builder Willem Moll was the key to this success. Marcel Minneart used this instrument to study stellar spectra at the Utrecht Astronomical Institute, and in particular for the Photometric Atlas of the Solar Spectrum. When the opportunity came in the 1960s to build instruments for research from space, it was natural that Kees de Jager opted for spectroscopy, in X-ray observations of the Sun. The expertise developed in this program allowed the Space Research Organisation of the Netherlands to be a principal player in the development of X-ray spectrographs on the Einstein, EXOSAT, Chandra and XMM-Newton satellites.

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<title>Description and performance of the low-energy transmission grating spectrometer on board Chandra</title>

Cited by 55 publications

References 2 publications

Establishing HZ43 A, Sirius B, and RX J185635-3754 as soft X-ray standards: a cross-calibration between the Chandra LETG+HRC-S, the EUVE spectrometer, and the ROSAT PSPC

Establishing HZ43 A, Sirius B, and RX J185635-3754 as soft X-ray standards: a cross-calibration between the Chandra LETG+HRC-S, the EUVE spectrometer, and the ROSAT PSPC

From ultraluminous X-ray sources to ultraluminous supersoft sources: NGC 55 ULX, the missing link

Spectroscopy in Utrecht: A Brief History

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