X-RAY PHASE-RESOLVED SPECTROSCOPY OF PSRs B0531+21, B1509–58, AND B0540–69 WITH RXTE

Abstract

The Rossi X-ray Timing Explorer (RXTE) has made hundreds of observations on three famous young pulsars (PSRs) B0531+21 (Crab), B1509-58, and B0540-69. Using the archive RXTE data, we have studied the phase-resolved spectral properties of these pulsars in details. The variation of the X-ray spectrum with phase of PSR B0531+21 is confirmed here much more precisely and more details are revealed than the previous studies: the spectrum softens from the beginning of the first pulse, turns to harden right at the pulse peak and becomes the hardest at the bottom of the bridge, softens gradually until the second peak, and then softens rapidly. Different from the previous studies, we found that the spectrum of PSR B1509-58 is significantly harder in the center of the pulse, which is also in contrast to that of PSR B0531+21. The variation of the X-ray spectrum of PSR B0540-69 seems similar to that of PSR B1509-58, but with a lower significance. Using the about 10 years of data span, we also studied the real time evolution of the spectra of these pulsars, and no significant evolution has been detected. We have discussed about the constraints of these results on theoretical models of pulsar X-ray emission.RXTE has made hundreds of observations on the three young pulsars that we studied, which were listed in Table. 3. The total exposure time of PSRs B0531+21, B1509-58, and B0540-69 is 172, 578, and 2,663 ks, respectively ( Table. 3), and with such plenty of data we can perform detailed phase-resolved spectroscopic study. The Event mode data were selected for our analyses, so as to have good time resolution and enough spectral channels.Heasoft (v6.10) was used to process the observational data as follows: (1) Create the filter file for each observation with XTEFILT; (2) generate the Good Time Interval (GTI) file by MAKETIME using the filter file; (3) using the GTI file to create the "good" events file with GROSSTIMEFILT; and (4) remove the clock events from the event mode data by SEFITER and FSELECT. The resulted new events data will be used in the timing and

Chandra Phase-resolved Spectroscopy of the High Magnetic Field Pulsar B1509−58

“…The radio pulse profile shows a sharp peak, while the X-ray profile has a single, broad, and asymmetric peak and lags the radio peak by about one quarter of the cycle (Kawai et al 1991). The broad X-ray pulse profile was conventionally described by two Gaussian components (Cusumano et al 2001;Ge -Chandra X-ray image of B1509 and its PWN in MSH 15-52 in the 0.5-7 keV band. All the X-ray events are projected onto the red dashed line in the CC mode observation to form a 1D image.…”

“…A pulse phase-resolved spectral analysis showed that Γ remains stable during the pulsed phase, such that the spectra of the two components of the pulse shape are indistinguishable (Rots et al 1998). Ge et al (2012) presented a more comprehensive phase-resolved spectral analysis using 15 years of RXTE data with a total exposure time of ∼578 ks. They treated the 0.2 cycles off-pulse emission as the background and found that Γ increases from 1.33 to 1.47 as the flux decreases.…”

Phase Evolution of the Crab Pulsar between Radio and X-Ray

“…As described in Ge et al (2012), the two asymmetrical pulses of the Crab pulsar in the X-ray band could be modeled by the formula (1) proposed by Nelson et al (1970). In this paper, we only fitted the shape of P1 of the X-ray profile to obtain its peak phase.…”

“…( 2004)) or (6.6 ± 1.3) × 10 −7 period per day (MJD 51955-55142, Ge et al (2012)). Here we analyze more observations, in a longer time range MJD 51955-55927, and both PCA and HEXTE showed the same trend with the change rates of (5.0 ± 0.9) × 10 −7 and (4.5 ± 0.9) × 10 −7 period per day, respectively.…”

“…Generally, the two dominant pulses in the radio band are denoted as main pulse (MP) and interpulse (IP; Lyne et al (2013)), and the two X-ray peaks are denoted as P1 and P2 (Kuiper et al 2001). Detailed studies show that the exact pulse morphology varies as a function of photon energy (Abdo et al 2010;Ge et al 2012) and the positions of the main peak in different energy bands are not exactly aligned, i.e., the optical, X-ray and γ-ray pulses lead to the radio pulses (Kuiper et al 2003;Rots et al 2004;Oosterbroek et al 2008;Abdo et al 2010;Molkov et al 2010). Recently, secular changes of both the radio and the X-ray profiles were found, though their change rates are different from each other (Lyne et al 2013;Ge et al 2016).…”