Radio Pulsar/X-ray Binary Link Archibald, Anne M; Stairs, Ingrid H; Ransom, Scott M ...
Science,
06/2009, Volume:
324, Issue:
5933
Journal Article
Peer reviewed
Open access
Radio pulsars with millisecond spin periods are thought to have been spun up by the transfer of matter and angular momentum from a low-mass companion star during an x-ray-emitting phase. The spin ...periods of the neutron stars in several such low-mass x-ray binary (LMXB) systems have been shown to be in the millisecond regime, but no radio pulsations have been detected. Here we report on detection and follow-up observations of a nearby radio millisecond pulsar (MSP) in a circular binary orbit with an optically identified companion star. Optical observations indicate that an accretion disk was present in this system within the past decade. Our optical data show no evidence that one exists today, suggesting that the radio MSP has turned on after a recent LMXB phase.
Over the last few years, the number of known eclipsing radio millisecond pulsar systems in the Galactic field has dramatically increased, with many being associated with Fermi gamma-ray sources. All ...are in tight binaries (orbital period < 24 hr) with many being classical “black widows” which have very low mass companions (companion mass Mc ≪ 0.1 M⊙) but some are “redbacks” with low mass (Mc ~ 0.2-0.4 M⊙) companions which are probably non-degenerate. These latter are systems where the mass transfer process may have only temporarily halted, and so are transitional systems between low mass X-ray binaries and ordinary binary millisecond pulsars. Here we review the new discoveries and their multi-wavelength properties, and briefly discuss models of shock emission, mass determinations, and evolutionary scenarios.
Abstract
The Dragonfly Nebula (G75.2+0.1) powered by the young pulsar J2021+3651 is a rare pulsar wind nebula (PWN) that shows double tori and polar jets enclosed by a bow-shock structure in X-rays. ...We present new radio observations of this source taken with the Very Large Array at 6 GHz. The radio PWN has an overall size about two times as large as the X-ray counterpart, consisting of a bright main-body region in the southwest, a narrow and fainter bridge region in the northeast, and a dark gap in between. The nebula shows a radio spectrum much softer than that of a typical PWN. This could be resulting from compression by the ram pressure as the system travels mildly supersonically in the interstellar medium. Our polarization maps reveal a highly ordered and complex
B
-field structure. This can be explained by a toroidal field distorted by the pulsar motion.
ABSTRACT We present results of a 400 ks Chandra observation of the young shell supernova remnant (SNR) G11.2−0.3, containing a pulsar and pulsar-wind nebula (PWN). We measure a mean expansion rate ...for the shell since 2000 of 0.0277 0.0018% yr−1, implying an age between 1400 and 2400 yr, and making G11.2−0.3 one of the youngest core-collapse SNRs in the Galaxy. However, we find very high absorption (AV ∼ 16m 2m), confirming near-IR determinations and ruling out a claimed association with the possible historical SN of 386 CE. The PWN shows strong jets and a faint torus within a larger, more diffuse region of radio emission and nonthermal X-rays. Central soft thermal X-ray emission is anticorrelated with the PWN; that, and more detailed morphological evidence, indicates that the reverse shock has already reheated all ejecta and compressed the PWN. The pulsar characteristic energy-loss timescale is well in excess of the remnant age, and we suggest that the bright jets have been produced since the recompression. The relatively pronounced shell and diffuse hard X-ray emission in the interior, enhanced at the inner edge of the shell, indicate that the immediate circumstellar medium into which G11.2−0.3 is expanding was quite anisotropic. We propose a possible origin for G11.2−0.3 in a stripped-envelope progenitor that had lost almost all its envelope mass, in an anisotropic wind or due to binary interaction, leaving a compact core whose fast winds swept previously lost mass into a dense irregular shell, and which exploded as a SN cIIb or Ibc.
PSR J2129−0429 is a 7.62 ms eclipsing millisecond pulsar (MSP) with a non-degenerate binary companion star that is likely in an early stage of the recycling process. It has one of the largest ...companion masses of a so-called "redback" (0.4 M ) and has an unusually high surface magnetic field (1.6 × 109 G) for an MSP. We present here an X-ray and optical study of PSR J2129−0429 using new NuSTAR and LCOGT data of the system in addition to archival Swift and XMM-Newton data. Its X-ray light curve shows strong orbital variation from the intra-binary shock, about five times greater than is typical for other systems, and is clearly and persistently double-peaked. Its X-ray spectrum has a very hard power-law component (Γ = 1.1-1.2) which extends to ∼40 keV and exhibits an efficiency of up to a few percent in the X-ray band. The X-ray spectrum at the second peak of the light curve exhibits strong variability, while the spectrum of the first peak remains constant across observations. The hardness of the spectrum is suggestive of driven magnetic reconnection occurring at the shock. In addition, we observe the companion to be currently optically brightening after a multi-year period where it was dimming. The changes in color suggest that it has been continually cooling, implying that the companion is currently expanding.
ABSTRACT
We present the first measurement of a non-zero magnetic field in the eclipsing material of a black widow pulsar. Black widows are millisecond pulsars which are ablating their companions; ...therefore they are often proposed as one potential source of isolated millisecond pulsars. PSR J2256–1024 is an eclipsing black widow discovered at radio wavelengths and later also observed in the X-ray and gamma parts of the spectrum. Here we present the radio timing solution for PSR J2256–1024; polarization profiles at 350, 820, and 1500 MHz; and an investigation of changes in the polarization profile due to eclipsing material in the system. In the latter we find evidence of Faraday rotation in the linear polarization shortly after eclipse, measuring a rotation measure of 0.44(6) rad m−2 and a corresponding line-of-sight magnetic field of ∼1.11(16) mG.
We provide timing solutions for 45 radio pulsars discovered by the Robert C. Byrd Green Bank Telescope. These pulsars were found in the Green Bank North Celestial Cap pulsar survey, an all-GBT-sky ...survey being carried out at a frequency of . We include pulsar timing data from the Green Bank Telescope and Low Frequency Array. Our sample includes five fully recycled millisecond pulsars (MSPs, three of which are in a binary system), a new relativistic double neutron star system, an intermediate-mass binary pulsar, a mode-changing pulsar, a 138 ms pulsar with a very low magnetic field, and several nulling pulsars. We have measured two post-Keplerian parameters and thus the masses of both objects in the double neutron star system. We also report a tentative companion mass measurement via Shapiro delay in a binary MSP. Two of the MSPs can be timed with high precision and have been included in pulsar timing arrays being used to search for low-frequency gravitational waves, while a third MSP is a member of the black widow class of binaries. Proper motion is measurable in five pulsars, and we provide an estimate of their space velocity. We report on an optical counterpart to a new black widow system and provide constraints on the optical counterparts to other binary MSPs. We also present a preliminary analysis of nulling pulsars in our sample. These results demonstrate the scientific return of long timing campaigns on pulsars of all types.
The origin of the high-frequency radio emission detected from several magnetars is poorly understood. In this paper, we report the ∼ 40 GHz properties of SGR J1745−29 measured using Jansky Very Large ...Array (JVLA) and Robert C. Byrd Green Bank Telescope (GBT) observations between 2013 October 26 and 2014 May 31. Our analysis of a Q-band (45 GHz) GBT observation on 2014 April 10 resulted in the earliest detection of pulsed radio emission at high frequencies ( 20 GHz ); we found that the average pulse has a singly peaked profile with width ∼ 75 ms (∼2% of the 3.764 s pulse period) and an average pulsed flux density of ∼100 mJy. We also detected very bright, short ( < 10 ms ) single pulses during ∼70% of this neutron star's rotations, and the peak flux densities of these bright pulses follow the same log-normal distribution as measured at 8.5 GHz. Additionally, our analysis of contemporaneous JVLA observations suggest that its 41/44 GHz flux density varied between ∼1-4 mJy during this period, with a ∼ 2 × change observed on ∼20 minute timescales during a JVLA observation on 2014 May 10. Such a drastic change over short timescales is inconsistent with the radio emission resulting from a shock powered by the magnetar's supersonic motion through the surrounding medium, but consistent with pulsed emission generated in its magnetosphere.
PDF
