The HEASARC welcomes your participation in a brief survey to capture how users access and utilize HEASARC data, software, and services. The outcome(s) of this survey will be used to guide, prioritize, and plan our activities and development in the coming years. It contains 18 questions, generally takes just a few minutes to complete, and your answers will remain totally anonymous. We thank you in advance for your valuable feedback.
The Salyut-4 space station was launched on 26 December 1974. It was in an
orbit with an apogee of 355 km and a perigee of 343 km. The orbital period
was 91.3 minutes. It was at an inclination of 51.6 degrees. The X-ray
telescope was switched on on 15 January 1975. Salyut-4 reentered the Earth's
atmosphere on 2 February 1977.
The Salyut-4 X-ray instrument, often called the Filin telescope, consisted of
four gas flow proportional counters, three of which have a total detection
surface of 450 sq cm in the energy range 2-10 keV, and one of which has an
effective surface of 37 sq cm for the range 0.2-2 keV. The field of view
was limited by a slit collimator to 3 deg x 10 deg FWHM. The instrumentation
also included optical sensors which were mounted on the outside of the station
together with the X-ray detectors, and power supply and measurement units
which were inside the station. Ground based calibration of the detectors is
considered along with in-flight operation in three modes: inertial
orientation, orbital orientation, and survey. Data could be collected in 4
energy channels: 2-3.1 keV, 3.1-5.9 keV, 5.9-9.6 keV, and 2-9.6 keV in the
larger detectors. The smaller detector had discriminator levels set at 0.2
keV, 0.55 keV, and 0.95 keV.
Among others, observations of Sco X-1, Cir X-1, Cyg X-1, and
A0620-00 were published from the Filin data. A highly variable low energy
(0.6-0.9 keV) flux was detected in Sco X-1. Cir X-1 was not detected at all
during a 5 July 1975 observation, providing an upper limit on the emission
of 3.5e-11 erg/sq-cm/s in the 0.2-2.0 keV range. Cyg X-1 was observed on
several occasions. Highly variable flux, in both the time and energy
domains, was observed.
The HEASARC welcomes your participation in a brief survey to capture how users access and utilize HEASARC data, software, and services. The outcome(s) of this survey will be used to guide, prioritize, and plan our activities and development in the coming years. It contains 18 questions, generally takes just a few minutes to complete, and your answers will remain totally anonymous. We thank you in advance for your valuable feedback.
