Improved position for the X-ray pulsar X1901+031
ATel #121; D. K. Galloway, R. Remillard, and E. Morgan (MIT)
on 25 Feb 2003; 22:28 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Duncan K. Galloway (duncan@space.mit.edu)
Subjects: Optical, X-ray, Request for Observations, Binary, Neutron Star, Transient, Pulsar
We report an improved position for the recurrent X-ray transient X1901+031 (ATEL #118). Based on an RXTE/PCA scan on Feb. 12, we derive a position of R.A. = 19h03m37.083s, Decl. = +3 11 31.20 (equinox J2000.0; estimated 1' uncertainty at 90-percent confidence). This position is 1.3' away from the previous ASM position, and 9' away from the nearest ROSAT source, 1RXS J190411.9+031210.
Measurements of the ~2.763 s pulse period between Feb. 10 and 25 show
variations suggesting orbital modulations with a period of ~25 d or
more. The ASM observations over the same time interval show a steady source with an average flux of 170 (5) mCrab and a hard spectrum (ratio of 5-12 keV to 3-5 keV ASM intensity = 2.6 (0.4)). RXTE observations are continuing.
