Engineering topics

Takeshima, T.

Publications and source records attributed to Takeshima, T..

4 records

NASA NTRS1998

XTE J1946+274 = GRO J1944+26

C. A. Wilson, M. H. Finger, R. S. Wilson, and D. M. Scott, Marshall Space Flight Center, NASA, report for the BATSE team: "Pulsations from a previously-uncatalogued x-ray pulsar in the Vul-Cyg region have been detected with BATSE in the energy band 20-50 keV from Sept. 8 through Sept. 14. A preliminary location (95-percent confidence) is bounded by R.A. = 19h 34m to 19h 54m and Decl. = +22o.5 to +30o.5 (equinox 2000.0). GRO J1944+26 rose from a 20-50-keV rms pulsed flux of < 15 mCrab on Sept. 7 to 27 +/- 3 mCrab on Sept. 13. Observations between Sept. 8 and 14 are consistent with a barycentric pulse frequency of 0.06315331 (6) Hz on Sept. 11.0 UT, with a frequency derivative of 2.2(2) x 10(exp -12) Hz/s. The pulse profile in the band 20-50 keV has a single asymmetric peak.

Smith, D. A.↗

NASA NTRS1996

X-ray search for dark lens objects

The quasi-stellar object (QSO) MG 2016+112 is searched for and probably identified as an X-ray cluster of galaxies by the Advanced Satellite for Cosmology and Astrophysics (ASCA) observations. The MG 2016+112 is a gravitational lensed system with three confirmed lensed images of the QSO at a redshift of 3.27. The X-ray spectrum suggests that the new record of the highest redshift of clusters of galaxies, from which X-ray and iron K-line emission were detected, was reached.

Hattori, M.↗

NASA NTRS1993

The discovery of pulsed iron line emission from Centaurus X-3

We present the first discovery of pulsed iron line emission from an X-ray binary, namely Cen X-3. Compared with the continuum pulsations, the iron line pulsations are shallow (50 percent change in amplitude), smeared (the profile is a single-peaked sinusoid) and phase-shifted (by about half a cycle). We also discuss the constraints on the origin of the line imposed by this discovery and by other observations.

Day, C. S. R.↗

NASA NTRS1992

Ginga observations of Centaurus X-3

Attention is given to a series of observations of Centaurus X-3 made with Ginga on March 22-24, 1989, over a complete orbital cycle. The data set includes a preeclipse dip, the eclipse ingress and egress, the eclipse itself, and a phase of high steady emission after egress. The mideclipse ephemeris obtained yields an estimate of the rate of change of the orbital period of -(1.738 +/- 0.004) x 10 exp 6/yr, confirming the rate of change reported by Kelley et al. (1983) and improving the precision by a factor of 20. The pulse profiles obtained with Ginga during the high postegress phase are double-peaked at low energies, and show a reversal of phase of 180 deg. No pulsations are detected during the eclipse and at low energies during the preeclipse dip, indicating that X-ray emission at these phases is due to scattering by extended matter. The energy of the iron emission line varies between 6.5 and 6.7 keV during the observation, while its equivalent width varies between 0.18 and 1.5 keV.

Nagase, F.↗