Rossi X-ray Timing Explorer was launched at the end
of 1995 and up to now (2004) it has been successfully operating for more
than 7 years. The mission was primarily designed to study the variability of
X-ray sources on time scales from sub-milliseconds to years.
The maneuvering capability of the satellite combined with the high
photon throughput of its main
detector (PCA) and high quality of background prediction (thanks to
PCA intrumental group of LHEA, GSFC) has also made it possible to
construct maps of the sky in energy band 3-20 keV. During its life time
RXTE/PCA has collected a large amount of data from slew observations
covering almost the entire sky.
We have utilized the slew parts of all RXTE/PCA
observations performed from April 15, 1996-July 16, 2002 which
amounts in total to approximately 50,000 observations. The exposure
time at a given point in the map is typically between 200-500 seconds.
The observational period before April 15, 1996
(High Voltage Epochs 1 and 2) was
excluded from the analysis because during that time the PCA had
significantly different gain and dependence of the effective area on
energy. The data reduction was done using standard tools of the
LHEASOFT with a set of packages written by M. Revnivtsev
(HEAD/IKI, Moscow; MPA, Garching).
The survey has several features. It has strongly different exposure times
at different points on the sky that lead to strong variability of the
statistical noise on images. Because of that the only meaningful
representation of images is the map in units of statistical significance.
After the detection of a source flux can be determined from the map
in the 'flux' units. Map resolution is determined mainly by
the slew rate of the RXTE (<0.05-0.1°;/sec) and the time resolution of
used data (16 sec, Std2 mode of the PCA). Sources can be detected down
to the level of ~6e-12 erg/s/cm2, but at this level the
confusion starts to play an important role. Details of the survey are
presented in the paper of Revnivtsev et al. (2004). Provenance: High Energy Astrophysics Department, Space Research Institute, Moscow, Russia; M
PA, Garching, Germany. This is a service of NASA HEASARC.
