Sub-Milliarcsecond Precision of Pulsar Motions: Using In-Beam Calibrators with the VLBA
نویسنده
چکیده
We present Very Long Baseline Array phase-referenced measurements of the parallax and proper motion of two pulsars, B0919+06 and B1857–26. Sub-milliarcsecond positional accuracy was obtained by simultaneously observing a weak calibrator source within the 40′ field of view of the VLBA at 1.5 GHz. We discuss the merits of using weak close calibrator sources for VLBI observations at low frequencies, and outline a method of observation and data reduction for these type of measurements. For the pulsar B1919+06 we measure a parallax of 0.31 ± 0.14 mas. The accuracy of the proper motions is ≈ 0.5 mas, an order of magnitude improvement over most previous determinations. Subject headings: astrometry—pulsars: general
منابع مشابه
21st Century Vlbi: Deep Wide-field Surveys
A 20-hour VLBI observation with the NRAO VLBA and GBT in the NOAO Boötes field reaches an rms noise of 9 microJy per beam at 1.4 GHz. Three sources were detected at 10-milliarcsecond resolution within the GBT primary beam of FWHM 8.6, including the 20milliJy calibrator and two sub-milliJy sources. By tapering the visibility data, portions of the VLBA primary beam of FWHM 29 were imaged at poore...
متن کاملHigh-precision VLBI astrometry of radio-emitting stars
Multiple-epoch phase-referenced VLBI observations of 11 radio-emitting stars have been conducted as part of an astrometric program to link the Hipparcos optical reference frame to the radio extragalactic reference frame. We present the VLBI positions, proper motions and trigonometric parallaxes from this program in the ICRF (International Celestial Reference Frame). These astrometric parameters...
متن کاملPrecision Astrometry with the Very Long Baseline Array: Parallaxes and Proper Motions for 14 Pulsars
Astrometry can bring powerful constraints to bear on a variety of scientific questions about neutron stars, including their origins, astrophysics, evolution, and environments. Using phase-referenced observations at the VLBA, in conjunction with pulsar gating and in-beam calibration, we have measured the parallaxes and proper motions for 14 pulsars. The smallest measured parallax in our sample i...
متن کاملThe Fifth Vlba Calibrator Survey: Vcs5
This paper presents the fifth part of the Very Long Baseline Array (VLBA) Calibrator Survey (VCS), containing 569 sources not observed previously with very long baseline interferometry in geodetic or absolute astrometry programs. This campaign has two goals: (i) to observe additional sources which, together with previous survey results, form a complete sample, (ii) to find new strong sources su...
متن کاملAn investigation on the performance of dose calibrators in nuclear medicine centers in Iran
Background: To investigate the status of the nuclear medicine (NM) centers in Iran for the performance of dose calibrators, 18 out of 54 centers providing NM services in Iran were randomly selected and inspected in 1997. In the first phase of the study the selected centers were inspected for performing of quality control (QC) tests of dose calibrators. The linearity of the activity res...
متن کامل