We present a pulse‐timing analysis of Rossi X‐ray Timing Explorer (RXTE) observations of the anomalous X‐ray pulsar 1E 2259+586 from its 2002 outburst to 2010 October. We have the following objectives: to extend the work on the recovery stage after the 2002 glitch; to investigate the variations caused by the second glitch that occurred in 2007; to look for other unusual events, if any, that arise in the regular spin‐down trend of the source. We find that the fractional change in the spin frequency derivative after the 2002 glitch is not stable as it decreased by an order of magnitude, from −2.2 × 10−2 to −1.278(3) × 10−3, in about 2.5 yr. Using a pulse‐timing analysis, we discover two small frequency shifts with fractional changes Δν/ν= 3.08(32) × 10−8 and Δν/ν=−1.39(11) × 10−8. While the first of these shifts is not found to have a fractional frequency derivative change, the second has . We interpret these frequency changes as positive and negative microglitches, similar to those seen in radio pulsars.

In this paper, we extend the timing analysis by Baykal et al. of Swift J1626.6−5156 using RXTE-PCA observations between MJD 53724 and MJD 55113 together with a Chandra-ACIS observation on MJD 54897 with a 20-ks exposure. We also present the X-ray spectral analysis of these RXTE and Chandra observations. We find that the spin-up rate of the source is correlated with the X-ray flux. Using this correlation, we estimate the distance and surface magnetic field of the source as ∼15 kpc and ∼9 × 10 11 G, respectively. From the spectral analysis, we find that the power-law index increases and hydrogen column density decreases with a decreasing flux.Key words: accretion, accretion discs -stars: neutron -pulsars: individual: Swift J1626.6−5156 -X-rays: binaries. The proposed optical companion of the source (2MASS16263652−5156305, USNO-B1.0 0380−0649488) was found to show strong Hα emission, which indicates that it is a Be star (Negueruela & Marco 2006). As the infrared magnitudes of the companion are rather large for a Be star, i.e. the star is unusually faint in the infrared band (J = 13.5, H = 13, K = 12.6; Rea et al. 2006), Swift J1626.6−5156 is thought to be an unusual Be/X-ray binary system. In this article, we extend the timing studies of Baykal et al. (2010) by including the analysis of RXTE-PCA observations between MJD 54410 and MJD 55113 and a Chandra-ACIS observation with a 20-ks exposure on MJD 54897. We also present X-ray spectral analysis of these RXTE and Chandra observations. In the next section, we describe the observations. In Sections 3 and 4, we present our timing and X-ray spectral analysis. In Section 5, we discuss our results. O B S E RVAT I O N SWe analysed the data from PCA on board RXTE (Jahoda et al. 1996) of Swift J1626.6−5156 between MJD 53724 and MJD 55113 with a total exposure of ∼449 ks, divided into 411 observations with exposures between ∼1 and ∼2 ks. We also note that this work includes a more detailed analysis of the RXTE-PCA data between MJD 53724 and 54410 which were used before by Baykal et al. (2010).The RXTE-PCA is an array of five Proportional Counter Units (PCUs) sensitive to the 2-60 keV energy range, with a total effective area of ∼7000 cm 2 and a field of view of ∼1• full width at half-maximum (FWHM). During the analysed RXTE-PCA observations, the number of active PCUs varied between one and four. Before MJD 53964, there were 1-2 ks long observations every 2-3 d. After MJD 53964, observations were sampled in pairs, containing two consecutive 1-2 ks long observations separated by ∼0.3-0.6 d. The two observations in each of these pairs were separated from each other by ∼9-10 d. In the timing analysis, we used all the available layers of PCUs. For the spectral analysis, we used the layers of PCU2 only.

Context. Low mass X-ray binaries are found to have very low frequency breaks in their power density spectra. The power density spectra below these breaks are nearly in white noise structure and at higher frequencies approximately follow the P ν ∝ ν −1.3 law. Aims. To determine whether high mass X-ray binary power density spectra have similar properties and the findings for low mass X-ray binaries are also valid for high mass binaries, we analyzed the time series of high mass X-ray binary sources produced by All Sky Monitor of Rossi X-ray Timing Explorer. Methods. We obtained the power density spectra of the high mass X-ray binaries using the cosine transform of autocorrelation function. Results. We identified break frequencies for seven sources, namely OAO 1657-415, SS 433, Vela X-1, SMC X-1, 4U 1700-377, GX 301-2, and LMC X-1. The normalized break frequencies with respect to the orbital frequency ( f break / f orbit ) for sources OAO 1657-415, SS 433, SMC X-1 and LMC X-1 are consistent with those of Roche lobe overflow systems. The other high mass X-ray binary systems, Vela X-1, GX 301-2, and 4U 1700-377, however, have larger break frequency ratios, f break / f orb , which are indicative of short viscous times. These are all wind-accreting sources and the stellar winds in the systems allow the formation of only short radius discs. Consequently, we qualitatively distinguished the Roche lobe overflow binaries from the wind accreting system by comparing their normalized break frequencies.

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