CCD soft X-ray imaging spectrometer for the ASCA satellite

Burke, Barry E.; Mountain, R. W.; Daniels, Peter J. L.; Cooper, Michael; Dolat, V.S.

doi:10.1109/23.281527

Cited by 144 publications

(80 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Bandpasses of the SIS and the GIS combined with the XRT are around 0.4-10 and 0.7-10 keV, respectively. The SISs have moderate spectral resolution of $130 eV at 5.9 keV and fields of view ( FOVs) of 20 0 ; 20 0 , with four CCD chips fabricated on each SIS ( Burke et al 1994;Yamashita et al 1999). A CCD chip needs 4 s to be read out, and runs of 1, 2, and 4 chips (corresponding to 1, 2, and 4 CCD modes) need 4, 8, and 16 s in an exposure, respectively.…”

Section: Target Selection and Data Reductionmentioning

confidence: 99%

X‐Ray Study of Herbig Ae/Be Stars

Hamaguchi

Yamauchi

Koyama

2005

ApJ

132

View full text Add to dashboard Cite

We present ASCA results of intermediate-mass pre-main-sequence ( PMS) stars, or Herbig Ae/Be (HAeBe) stars. Among the 35 ASCA pointed sources, we detect 11 plausible X-ray counterparts. X-ray luminosities of the detected sources in the 0.5-10 keV band are in the range of log L X $ 30 32 ergs s À1 , which is systematically higher than those of low-mass PMS stars. This fact suggests that the contribution of a possible low-mass companion is not large. Most of the bright sources show significant time variation; in particular, two HAeBe stars-MWC 297 and TY CrA-exhibit flarelike events with long decay timescales (e-folding time $10À60 ks). These flare shapes are similar to those of low-mass PMS stars. The X-ray spectra are successfully reproduced by an absorbed one-or two-temperature thin-thermal plasma model. The temperatures are in the range of kT $ 1 5 keV, significantly higher than those of main-sequence OB stars (kT < 1 keV). These X-ray properties are not explained by wind-driven shocks, but are more likely due to magnetic activity. On the other hand, the plasma temperature rises as absorption column density increases or as HAeBe stars ascend to earlier phases. The X-ray luminosity reduces after stellar age of a few times 10 6 yr. X-ray activity may be related to stellar evolution. The age of the activity decay is apparently near the termination of jet or outflow activity. We thus hypothesize that magnetic activity originates from the interaction of the large-scale magnetic fields coupled to the circumstellar disk. We also discuss differences in X-ray properties between HAeBe stars and main-sequence OB stars.

show abstract

Section: Target Selection and Data Reductionmentioning

confidence: 99%

X‐Ray Study of Herbig Ae/Be Stars

Hamaguchi

Yamauchi

Koyama

2005

ApJ

132

View full text Add to dashboard Cite

show abstract

“…Two sets of the Solid-State Imaging Spectrometers (SISs) were operated in parallel with the Gas Imaging Spectrometers (GISs), both located separately at foci of four identical thin-foil X-ray telescopes (XRTs). Details of this instrumentation are found in Serlemitsos et al (1995), Burke et al (1991Burke et al ( , 1994, Yamashita et al (1997), Ohashi et al (1996), and Makishima et al (1996), while a general description of ASCA can be found in Tanaka, Inoue, & Holt (1994).…”

Section: Observationsmentioning

confidence: 99%

Further Studies of 1E 1740.7−2942 withASCA

Sakano

Imanishi

Tsujimoto

et al. 1999

ApJ

View full text Add to dashboard Cite

We report the ASCA results of the Great Annihilator 1E 1740.7[2942 obtained with Ðve pointing observations in a time span of 3.5 yr. The X-ray spectrum for each period is well Ðtted with a single power law absorbed by a high column of gas. The X-ray Ñux changes by a factor of 2 from period to period, but the other spectral parameters show no signiÐcant change. The photon index is Ñat with ! \ 0.9È1.3. The column density of hydrogen is D1.0 ] 1023 H cm~2 and that of iron is N H N Fe D1019 Fe cm~2. These large column densities indicate that 1E 1740.7[2942 is near the Galactic center. The column density ratio leads the iron abundance to be 2 times larger than the other elements in a unit of the solar ratio. The equivalent width of the Ka line from a neutral iron is less than 15 eV in 90% conÐdence. This indicates that the iron column density within several parsecs from 1E 1740.7[2942 is less than 5 ] 1017 Fe cm~2. In addition, the derived hydrogen column density is about one-sixth of that of giant molecular clouds in the line of sight. All these facts support the fact that 1E 1740.7[2942 is not in a molecular cloud, but possibly in front of it ; the X-rays are not powered by accretion from a molecular cloud, but from a companion star like ordinary X-ray binaries.

show abstract

“…In comparing the surface brightness of the LGC and LSS, we used only data from the Gas Imaging Spectrometer (GIS; Ohashi et al 1996) coupled to the X-ray telescope (XRT; Serlemitsos et al 1995), primarily because of its larger solid angle than that of the Solid State Imaging Spectrometer (SIS; Burke et al 1994). Moreover, the evaluation of the non X-ray Background (NXB) is well established and the stability of the detector performance has also been confirmed for the GIS, which is suitable for our purpose of searching very extended and faint X-ray emission.…”

Section: Data Screening and Non X-ray Backgroundmentioning

confidence: 99%

Search for hot gas in the local group with ASCA

Osone

Makishima

Matsuzaki

et al. 2000

Advances in Space Research

View full text Add to dashboard Cite

An X-ray study was made to examine whether some part of the soft X-ray background is coming from hot gas in the Local Group. For this purpose, four consecutive pointings were made with ASCA toward a sky region between M 31 and M 33, which is close to the direction of the center of the Local Group. By comparing the X-ray surface brightness in this sky direction with that in another blank sky region near the north equatorial pole, an upper limit on any soft excess X-ray background was determined to be 2.8×10 −9 erg cm −2 s −1 sr −1 with a 90% confidence level statistical error. Assuming an optically thin thermal bremsstrahlung energy spectrum (Raymond-Smith model) for a temperature of 1 keV and a β-model electron density distribution for a core radius of 100 kpc for the X-ray halo, the upper limit of the central plasma density was obtained to be 1.3×10 −4 cm −3 . The plasma column density is too low to contribute significantly to the observed quadrupole anisotropy in the cosmic microwave background.

show abstract

CCD soft X-ray imaging spectrometer for the ASCA satellite

Cited by 144 publications

References 21 publications

X‐Ray Study of Herbig Ae/Be Stars

X‐Ray Study of Herbig Ae/Be Stars

Further Studies of 1E 1740.7−2942 withASCA

Search for hot gas in the local group with ASCA

Contact Info

Product

Resources

About