arXiv subjects

M. J. Pivovaroff

Publications and source records attributed to M. J. Pivovaroff.

43 records · Page 3Linked to original sources

arXiv2001

A Sensitive Targeted Search Campaign at Parkes to Find Young Radio Pulsars at 20 cm

We describe a sensitive targeted search campaign at Parkes to find faint young radio pulsars using the center beam of the 20-cm multibeam receiver. The high frequency of the receiver mitigates scattering effects which can dominate profiles of distant pulsars at low frequencies and prevent detection. The targets included several composite supernova remnants (SNRs), two fast X-ray pulsars, long-period anomalous X-ray pulsars, and a soft gamma repeater. The sensitivity limits in this search are significantly better than those previously reported for these objects. We have discovered three new radio pulsars, two of which are not associated with the target objects. The third pulsar, PSR J1713-3949, is possibly associated with SNR G347.3-0.5; the estimated ages and distances of the two objects are consistent, but a more significant positional coincidence must be established with the central X-ray source in the SNR through pulsar timing to confirm or refute the association.

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arXiv2001

SNR G292.2-0.5: A Radio Supernova Remnant Associated with the Young Pulsar J1119-6127

We report on Australia Telescope Compact Array observations in the direction of the young high-magnetic-field radio pulsar PSR J1119-6127. In the resulting images we identify a non-thermal radio shell of diameter 15 arcminutes, which we classify as a previously uncataloged young supernova remnant (SNR), G292.2-0.5. This SNR is positionally coincident with PSR J1119-6127, and we conclude that the two objects are physically associated. No radio emission is detected from any pulsar wind nebula (PWN) associated with the pulsar; our observed upper limits are consistent with the expectation that high-magnetic-field pulsars produce radio nebulae which fade rapidly. This system suggests a possible explanation for the lack of associated radio pulsars and/or PWNe in many SNRs.

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arXiv2001

Chandra observations of the pulsar wind nebula in SNR G0.9+0.1

We present observations with the Chandra X-ray Observatory of the pulsar wind nebula (PWN) within the supernova remnant G0.9+0.1. At Chandra's high resolution, the PWN has a clear axial symmetry; a faint X-ray point source lying along the symmetry axis possibly corresponds to the pulsar itself. We argue that the nebular morphology can be explained in terms of a torus of emission in the pulsar's equatorial plane and a jet directed along the pulsar spin axis, as is seen in the X-ray nebulae powered by other young pulsars. A bright clump of emission within the PWN breaks the axisymmetry and may correspond to an intermediate-latitude feature in the pulsar wind.

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arXiv2001

X-ray Observations of the New Pulsar--Supernova Remnant System PSR J1119-6127 and SNR G292.2-0.5

PSR J1119-6127 is a recently discovered 1700-year-old radio pulsar that has a very high inferred surface dipolar magnetic field. We present a detailed analysis of a pointed ASCA observation and archival ROSAT data of J1119-6127 and its surroundings. Both data sets reveal extended emission coincident with the newly-discovered radio supernova remnant G292.2-0.5, reported in a companion paper by Crawford et al. (astro-ph/0012287).. A hard point source, offset ~1.5' from the position of the radio pulsar, is seen with the ASCA GIS. No pulsations are detected at the radio period with a pulsed fraction upper limit of 61% (95% confidence). The limited statistics prevent a detailed spectral analysis, although a power-law model with photon index (Gamma=~1-2) describes the data well. Both the spectral model and derived X-ray luminosity are consistent with those measured for other young radio pulsars, although the spatial offset renders an identification of the source as the X-ray counterpart of the pulsar uncertain.

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arXiv2000

A radio supernova remnant associated with the young pulsar J1119-6127

We report on Australia Telescope Compact Array observations in the direction of the young high magnetic-field pulsar J1119-6127. In the resulting images we identify a non-thermal radio shell of diameter 15', which we classify as a previously uncatalogued young supernova remnant, G292.2-0.5. This supernova remnant is positionally coincident with PSR J1119-6127, and we conclude that the two objects are physically associated. No radio emission is detected from any pulsar wind nebula (PWN) associated with the pulsar; our observed upper limits are consistent with the expectation that high magnetic-field pulsars produce radio nebulae which fade rapidly. This system suggests a possible explanation for the lack of an associated radio pulsar and/or PWN in many supernova remnants.

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arXiv2000

ASCA observations of the young rotation-powered pulsars PSR B1046-58 and PSR B1610-50

We present X-ray observations of two young energetic radio pulsars, PSRs B1046-58 and B1610-50, and their surroundings, using archival data from the Advanced Satellite for Cosmology and Astrophysics (ASCA). The energetic pulsar PSR B1046-58 is detected in X-rays with a significance of 4.5 sigma. The unabsorbed flux, estimated assuming a power-law spectrum and a neutral hydrogen column density N_H of 5E21 cm^-2 is (2.5 +/- 0.3) x 10E-13 ergs/cm^2/s in the 2-10 keV band. Pulsed emission is not detected; the pulsed fraction is less than 31% at the 90% confidence level for a 50% duty cycle. We argue that the emission is best explained as originating from a pulsar-powered synchrotron nebula. The X-ray counterpart of the pulsar is the only hard source within the 95% error region of the previously unidentified gamma-ray source 3EG J1048-5840. This evidence supports the results of Kaspi et al. (1999), who in a companion paper, suggest that PSR B1046-58 is the counterpart to 3EG J1048-5840. X-ray emission from PSR B1610-50 is not detected. Using similar assumptions as above, the derived 3 sigma upper limit for the unabsorbed 2-10 keV X-ray flux is 1.5E-13 ergs/cm^2/s. We use the flux limit to estimate the pulsar's velocity to be less than ~170 km/s, casting doubt on a previously reported association between PSR B1610-50 and supernova remnant Kes 32. Kes 32 is detected, as is evident from the correlation between X-ray and radio emission. The ASCA images of PSR B1610-50 are dominated by mirror-scattered emission from the X-ray-bright supernova remnant RCW 103, located 33' away. We find no evidence for extended emission around either pulsar, in contrast to previous reports of large nebulae surrounding both pulsars.

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arXiv2000

X-ray observations of the high magnetic field radio pulsar PSR J1814-1744

PSR J1814-1744 is a 4 s radio pulsar with surface dipole magnetic field strength 5.5*10^13 G, inferred assuming simple magnetic dipole braking. This pulsar's spin parameters are very similar to those of anomalous X-ray pulsars (AXPs), suggesting that this may be a transition object between the radio pulsar and AXP population, if AXPs are isolated, high magnetic field neutron stars as has recently been hypothesized. We present archival X-ray observations of PSR J1814-1744 made with ROSAT and ASCA. X-ray emission is not detected from the position of the radio pulsar. The derived upper flux limit implies an X-ray luminosity significantly smaller than those of all known AXPs. This conclusion is insensitive to the possibility that X-ray emission from PSR J1814-1744 is beamed or that it undergoes modest variability. When interpreted in the context of the magnetar mechanism, these results argue that X-ray emission from AXPs must depend on more than merely the inferred surface magnetic field strength. This suggests distinct evolutionary paths for radio pulsars and AXP, despite their proximity in period--period derivative phase space.

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