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Publication
Featured researches published by H. Bradt.
The Astrophysical Journal | 1976
Jeffrey E. McClintock; S. Rappaport; P. C. Joss; H. Bradt; J. Buff; G. W. Clark; D. R. Hearn; W. H. G. Lewin; T. Matilsky; W. Mayer; F. Primini
A 283 s periodic pulsation in the X-ray system 3U 0900--40 has been discovered during observations by the SAS-3 X-ray observatory. Pulse profiles of the 283 s periodicity are presented in five energy intervals covering the range 1--30 keV for the period 1975 July 19.4--23.9. The averaged profile is relatively simple at higher energies and is markedly more complex at lower energies. The peak 1--40 keV intensity observed for the source is 1.2 x 10/sup -8/ ergs cm/sup -2/ s/sup -1/, which corresponds to a luminosity of 2.1 x 10/sup 36/ ergs s/sup -1/ at a distance of 1.2 kpc. A search for soft X-ray emission (E<1 keV) yielded upper limits of 2 x 10/sup -11/ and 5 x 10/sup -11/ ergs cm/sup -2/ s/sup -1/ in the energy intervals 0.16--0.28 keV and 0.5--0.7 keV, respectively. (AIP)
The Astrophysical Journal | 1970
Herbert W. Schnopper; H. Bradt; S. Rappaport; E. Boughan; B. Burnett; R. Doxsey; W. Mayer; S. Watt
X ray sources celestial positions in Sagittarius region, using rocket-borne rotating modulation collimator
The Astrophysical Journal | 1976
H. Bradt; W. Mayer; J. Buff; G. W. Clark; R. Doxsey; D. R. Hearn; G. Jernigan; P. C. Joss; B. Laufer; W. H. G. Lewin; F. Li; T. Matilsky; Jeffrey E. McClintock; F. Primini; S. Rappaport; Herbert W. Schnopper
Light curves of the 104 s periodicity in the transient X-ray source in Taurus (A0535+26) are presented for six energy intervals in the range 1-35 keV for the period 1975 May 30-June 2. The pulse structure ranges from an apparently simple modulation at higher energies to a very complex pattern at lower energies. No Doppler shift is observed in the 104 s pulse period during the three days of observations. This places severe constraints upon possible binary orbital motion. Upper limits on the power at other periodicities are approximately-less-than10 percent for 2 ms-2s and approximately-less-than2 percent for 2 s-2000 s. (AIP)
The Astrophysical Journal | 1976
R. Doxsey; G. Jernigan; D. R. Hearn; H. Bradt; J. Buff; G. W. Clark; J. P. Delvaille; A. Epstein; P. C. Joss; T. Matilsky; W. Mayer; Jeffrey E. McClintock; S. Rappaport; J. A. Richardson; Herbert W. Schnopper
The X-ray nova A0620-00 (Nova Monocerotis 1975) has been observed with the SAS-3 satellite. The 1--10 keV intensity was observed to increase by a factor of 2.3 from August 8 to August 11. It reached and maintained a constant intensity of 1.7x10
The Astrophysical Journal | 1973
G. W. Clark; H. Bradt; W. H. G. Lewin; Thomas H. Markert; Herbert W. Schnopper; G. F. Sprott
sup -6
The Astrophysical Journal | 1976
D. R. Hearn; J. A. Richardson; H. Bradt; G. W. Clark; W. H. G. Lewin; W. Mayer; Jeffrey E. McClintock; F. Primini; S. Rappaport
ergs cm
The Astrophysical Journal | 1977
J. Buff; G. Jernigan; B. Laufer; H. Bradt; G. W. Clark; W. H. G. Lewin; T. Matilsky; W. Mayer; F. Primini
sup -2
The Astrophysical Journal | 1972
G. W. Clark; H. Bradt; W. H. G. Lewin; T. H. Markert; Herbert W. Schnopper; G. F. Sprott
s
The Astrophysical Journal | 1974
G. F. Sprott; H. Bradt; G. W. Clark; W. H. G. Lewin; Herbert W. Schnopper; L. Pigatto; L. Rosino
sup -1
Archive | 1976
H. Bradt; T. Matilsky
from August 11 to August 13. Limits on periodicities of less than or approximately equal to 2 percent of the power were obtained for periods from 0.2 ms to 435 s. A precise position was obtained with the SAS-3 modulation collimators on August 15. This led directly to optical and radio identifications. Observations with the SAS-3 low-energy concentrator system on August 27 showed an intense 0.4--0.8 keV flux emanating from the nova. A hydrogen column density of (3.5+-0.3) x10
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