590049
Precision Timing of Two Anomalous X-Ray Pulsars.
We report on long-term X-ray timing of two anomalous X-ray pulsars, 1RXS J170849.0-400910 and 1E 2259+586, using the Rossi X-Ray Timing Explorer. In monthly observations made over 1.4 and 2.6 yr for the two pulsars, respectively, we have obtained phase-coherent timing solutions which imply that these objects have been rotating with great stability throughout the course of our observations. For 1RXS J170849.0-400910, we find a rotation frequency of 0.0909169331(5) Hz and frequency derivative -15.687&parl0;4&parr0;x10-14 Hz s-1 for epoch MJD 51215.931. For 1E 2259+586, we find a rotation frequency of 0.1432880613(2) Hz and frequency derivative -1.0026&parl0;7&parr0;x10-14 Hz s-1 for epoch MJD 51195.583. The rms phase residuals from these simple models are only approximately 0.01 cycles for both sources. We show that the frequency derivative for 1E 2259+586 is inconsistent with that inferred from incoherent frequency observations made over the last 20 yr. Our observations are consistent with the magnetar hypothesis and make binary accretion scenarios appear unlikely.
7067432
RXTE Observations of PSR J1105-6107
We report on X-ray observations of the young, energetic radio pulsar PSR J1105-6107 obtained using the Rossi X-ray Timing Explorer. Our timing analysis of Proportional Counter Array data finds no evidence for X-ray pulsations from this source. We set a new upper limit on the pulsed X-ray flux from the pulsar of 18% in the 2-10 keV band, for a duty cycle of 0.5. Our improved upper limit supports the hypothesis that the X-ray emission seen by the ASCA X-ray satellite in the direction of PSR J1105-6107 is the result of a pulsar-powered synchrotron nebula.
8119119
LARGE ANGULAR SCALE POLARIZATION OF THE COSMIC MICROWAVE BACKGROUND RADIATION AND THE FEASIBILITY OF ITS DETECTION
In addition to its spectrum and temperature anisotropy, the 2.7 K cosmic microwave background (CMB) is also expected to exhibit a low level of polarization. The spatial power spectrum of the polar- ization can provide details about the formation of structure in the universe as well as its ionization history. Here we calculate the magnitude of the CMB polarization in various cosmological scenarios, with both an analytic and a numerical method. We then outline the fundamental challenges to measur- ing these signals and focus on two of them: achieving adequate sensitivity and removing contamination due to foreground sources. We describe the design of a ground-based instrument (Polarization Obser- vations of Large Angular Regions) that could detect polarization of the CMB at large angular scales in the next few years. Subject headings: cosmic microwave background E cosmology: theory E polarization
117445749
PRESENT STATUS OF EXPERIMENTAL RESULTS RELATING TO CP VIOLATION.