Discovery of a 283-second periodic variation in the X-ray source 3U 0900--40

Journal Article · Tue Jun 01 04:00:00 EDT 1976 · Astrophys. J., Lett.; (United States)

DOI:https://doi.org/10.1086/182142· OSTI ID:7341149

McClintock, J E; Rappaport, S; Joss, P C; Bradt, H; Buff, J; Clark, G W; Hearn, D; Lewin, W H.G.; Matilsky, T; Mayer, W; Primini, F

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)

• Research Organization: Department of Physics and Center for Space Research, Massachusetts Institute of Technology
• OSTI ID: 7341149
• Journal Information: Astrophys. J., Lett.; (United States), Journal Name: Astrophys. J., Lett.; (United States) Vol. 206:2; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics &amp; Cosmology-- Quasi-Stellar
Radio
&amp; X-Ray Sources-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BINARY STARS
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
NEUTRON STARS
PULSARS
PULSATIONS
RADIATIONS
SOFT X RADIATION
STARS
VARIABLE STARS
X RADIATION