<i>Chandra</i>Observations of the Transient 7 s X‐ray Pulsar AX J1845.0−0258

Tam, Cindy R.; Kaspi, V. M.; Gaensler, B. M.; Gotthelf, E. V.

doi:10.1086/507262

Cited by 34 publications

(40 citation statements)

References 24 publications

(46 reference statements)

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“…Tam et al (2006) argue that the recent flux data of AX J1845−0258 may be from another unrelated source within the error circles. Because of this ambiguity, we did not include this source in the present work.…”

Section: Application Of the Model To The X-ray Enhancement Light Curvmentioning

confidence: 83%

On the X-Ray Outbursts of Transient Anomalous X-Ray Pulsars and Soft Gamma-Ray Repeaters

Çalışkan¹,

Ertan²

2012

ApJ

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We show that the X-ray outburst light curves of four transient anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs), namely, XTE J1810−197, SGR 0501+4516, SGR 1627−41, and CXOU J164710.2−455216, can be produced by the fallback disk model that was also applied to the outburst light curves of persistent AXPs and SGRs in our earlier work. The model solves the diffusion equation for the relaxation of a disk that has been pushed back by a soft gamma-ray burst. The sets of main disk parameters used for these transient sources are very similar to each other and to those employed in our earlier models of persistent AXPs and SGRs. There is a characteristic difference between the X-ray outburst light curves of transient and persistent sources. This can be explained by the differences in the disk surface density profiles of the transient and persistent sources in quiescence indicated by their quiescent X-ray luminosities. Our results imply that a viscous disk instability operating at a critical temperature in the range of ∼1300-2800 K is a common property of all fallback disks around AXPs and SGRs. The effect of the instability is more pronounced and starts earlier for the sources with lower quiescent luminosities, which leads to the observable differences in the X-ray enhancement light curves of transient and persistent sources. A single active disk model with the same basic disk parameters can account for the enhancement phases of both transient and persistent AXPs and SGRs. We also present a detailed parameter study to show the effects of disk parameters on the evolution of the X-ray luminosity of AXPs and SGRs in the X-ray enhancement phases.

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Section: Application Of the Model To The X-ray Enhancement Light Curvmentioning

confidence: 83%

On the X-Ray Outbursts of Transient Anomalous X-Ray Pulsars and Soft Gamma-Ray Repeaters

Çalışkan¹,

Ertan²

2012

ApJ

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“…Given the spectacular radiative outburst contemporaneous with the large 2002 1E 2259+586 glitch, we can speculate that larger angular momentum transfers that occur in radio pulsars could result in even more dramatic outbursts in affected AXPs, possibly like those seen in XTE 1810−197 (Ibrahim et al 2004) and in the AXP candidate AX J1845−0258 (Tam et al 2006). Indeed a recent X-ray burst observed from CXOU J164710.2−455216 (Muno et al 2007) has been claimed to be accompanied by a very large (∆ν/ν ≃ 6×10 −5 , ∆ν ≃ 6×10 −6 ) glitch (Israel et al 2007a), and AXP 1E 1048.1−5937 recently exhibited a large glitch and flux increase (Dib et al 2007b, Dib et al, in prep.).…”

Section: Axp Glitchesmentioning

confidence: 98%

Glitches in Anomalous X-ray Pulsars

Dib

Kaspi

Gavriil

2008

AIP Conference Proceedings

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We report on 8.7 and 7.6 yr of Rossi X-ray Timing Explorer (RXTE) observations of the Anomalous X-ray Pulsars (AXPs) RXS J170849.0−400910 and 1E 1841−045, respectively. These observations, part of a larger RXTE AXP monitoring program, have allowed us to study the long-term timing, pulsed flux, and pulse profile evolution of these objects. We report on four new glitches, one from RXS J170849.0−400910 and three from 1E 1841−045. One of the glitches from 1E 1841−045 is among the largest ever seen in a neutron star in terms of fractional frequency increase. With nearly all known persistent AXPs now seen to glitch, such behavior is clearly generic to this source class. We show that in terms of fractional frequency change, AXPs are among the most actively glitching neutron stars, with glitch amplitudes in general larger than in radio pulsars. However, in terms of absolute glitch amplitude, AXP glitches are unremarkable. We show that the largest AXP glitches observed thus far have recoveries that are unusual among those of radio pulsar glitches, with the combination of recovery time scale and fraction yielding changes in spin-down rates following the glitch similar to, or larger than, the long-term average. We also observed a large longterm fractional increase in the magnitude of the spin-down rate of 1E 1841−045, following its largest glitch, with ∆ν/ν = 0.1. These observations are challenging to interpret in standard glitch models, as is the frequent occurence of large glitches given AXPs' high measured temperatures. We speculate that the stellar core may be involved in the largest AXP glitches. Furthermore, we show that AXP glitches appear to fall in two classes: radiatively loud and radiatively quiet. The latter, of which the glitches of RXS J170849.0−400910 and 1E 1841−045 are examples, show little evidence for an accompanying radiative event such as a sudden flux increase or pulse profile change. We also show, however, that pulse profile and pulsed flux changes are common in these AXPs, but do not apprear closely correlated with any timing behavior.

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“…1-left). In addition to the three Chandra sources reported in Tam et al (2006) (labelled here as source F, O and R), the EPIC data reveal the presence of 7 new sources inside (or slightly outside) the error regions of AX J1845-0258. All of them are detected at 3σ in at least one of the considered energy ranges (0.3-10 keV, 0.3-2 keV, and 2-10 keV).…”

Section: Data Analysis and Resultsmentioning

confidence: 85%

A new investigation of the possible X-ray counterparts of the magnetar candidate AX J1845−0258

Pintore¹,

Mereghetti²

2016

Mon. Not. R. Astron. Soc.

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AX J1845-0258 is a transient X-ray pulsar, with spin period of 6.97s, discovered with the ASCA satellite in 1993. Its soft spectrum and the possible association with a supernova remnant suggest that AX J1845-0258 might be a magnetar, but this has not been confirmed yet. A possible counterpart one order of magnitude fainter, AX J184453-025640, has been found in later X-ray observations, but no pulsations have been detected. In addition, some other X-ray sources are compatible with the pulsar location, which is in a crowded region of the Galactic plane. We have carried out a new investigation of all the X-ray sources in the ASCA error region of AX J1845-0258, using archival data obtained with Chandra in 2007 and 2010, and with XMM-Newton in 2010. We set an upper limit of 6% on the pulsed fraction of AX J184453-025640 and confirmed its rather hard spectrum (power law photon index of 1.2±0.3). In addition to the other two fainter sources already reported in the literature, we found other X-ray sources positionally consistent with AX J1845-0258. Although many of them are possibly foreground stars likely unrelated to the pulsar, at least another new source, CXOU J184457.5-025823, could be a plausible counterpart of AX J1845-0258. It has a flux of 6 × 10 −14 erg cm −2 s −1 and a spectrum well fit by a power law with photon index ∼ 1.3 and N H ∼ 10 22 cm −2 .

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ChandraObservations of the Transient 7 s X‐ray Pulsar AX J1845.0−0258

Cited by 34 publications

References 24 publications

On the X-Ray Outbursts of Transient Anomalous X-Ray Pulsars and Soft Gamma-Ray Repeaters

On the X-Ray Outbursts of Transient Anomalous X-Ray Pulsars and Soft Gamma-Ray Repeaters

Glitches in Anomalous X-ray Pulsars

A new investigation of the possible X-ray counterparts of the magnetar candidate AX J1845−0258

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