scholarly journals The SUrvey for Pulsars and Extragalactic Radio Bursts – IV. Discovery and polarimetry of a 12.1-s radio pulsar

2020 ◽  
Vol 493 (1) ◽  
pp. 1165-1177 ◽  
Author(s):  
V Morello ◽  
E F Keane ◽  
T Enoto ◽  
S Guillot ◽  
W C G Ho ◽  
...  
Keyword(s):  
Position Angle ◽  
Radio Pulsar ◽  
Vector Model ◽  
Dispersion Measure ◽  
Radio Bursts ◽  
Free Electron Density ◽  
X Ray ◽  
Surface Magnetic Field ◽  
Spin Period ◽  
P Parameter

ABSTRACT We report the discovery of PSR J2251−3711, a radio pulsar with a spin period of 12.1 s, the second longest currently known. Its timing parameters imply a characteristic age of 15 Myr, a surface magnetic field of 1.3 × 1013 G, and a spin-down luminosity of 2.9 × 1029 erg s−1. Its dispersion measure of 12.12(1) pc cm−3 leads to distance estimates of 0.5 and 1.3 kpc according to the NE2001 and YMW16 Galactic free electron density models, respectively. Some of its single pulses show an uninterrupted 180-deg sweep of the phase-resolved polarization position angle, with an S-shape reminiscent of the rotating vector model prediction. However, the fact that this sweep occurs at different phases from one pulse to another is remarkable and without straightforward explanation. Although PSR J2251−3711 lies in the region of the $P-\dot{P}$ parameter space occupied by the X-ray isolated neutron stars (XINS), there is no evidence for an X-ray counterpart in our Swift XRT observation; this places a 99 per cent-confidence upper bound on its unabsorbed bolometric thermal luminosity of $1.1 \times 10^{31}~(d / 1~\mathrm{kpc})^2~\mathrm{erg\, s}^{-1}$ for an assumed temperature of 85 eV, where d is the distance to the pulsar. Further observations are needed to determine whether it is a rotation-powered pulsar with a true age of at least several Myr, or a much younger object such as an XINS or a recently cooled magnetar. Extreme specimens like PSR J2251−3711 help bridge populations in the so-called neutron star zoo in an attempt to understand their origins and evolution.

scholarly journals On the magnetoionic environments of fast radio bursts

2020 ◽  
Vol 499 (1) ◽  
pp. 355-361 ◽  
Author(s):  
Wei-Yang Wang ◽  
Bing Zhang ◽  
Xuelei Chen ◽  
Renxin Xu
Keyword(s):  
Magnetic Field ◽  
Mean Value ◽  
Line Of Sight ◽  
Galactic Centre ◽  
Dispersion Measure ◽  
Radio Bursts ◽  
Host Galaxies ◽  
Surface Magnetic Field ◽  
Rotation Measure ◽  
The Mean

ABSTRACT Observations of the Faraday rotation measure, combined with the dispersion measure, can be used to infer the magnetoionic environment of a radio source. We investigate the magnetoionic environments of fast radio bursts (FRBs) by deriving their estimated average magnetic field strengths along the line of sight 〈B∥〉 in their host galaxies and comparing them with those of Galactic pulsars and magnetars. We find that for those FRBs with RM measurements, the mean 〈B∥〉 are $1.77^{+9.01}_{-1.48}\, \rm \mu G$ and $1.74^{+14.82}_{-1.55}\, \rm \mu G$ using two different methods, which is slightly larger but not inconsistent with the distribution of Galactic pulsars, $1.00^{+1.51}_{-0.60}\, \rm \mu G$. Only six Galactic magnetars have estimated 〈B∥〉. Excluding PSR J1745–2900 that has an anomalously high value due to its proximity with the Galactic Centre, the other five sources have a mean value of $1.70\, \rm \mu G$, which is statistically consistent with the 〈B∥〉 distributions of both Galactic pulsars and FRBs. There is no apparent trend of evolution of magnetar 〈B∥〉 as a function of age or surface magnetic field strength. Galactic pulsars and magnetars close to the Galactic Centre have relatively larger 〈B∥〉 values than other pulsars/magnetars. We discuss the implications of these results for the magnetoionic environments of FRB 121102 within the context of magnetar model and the model invoking a supermassive black hole, and for the origin of FRBs in general.

scholarly journals Chandra Observations of the Guitar Nebula

2003 ◽  
Vol 214 ◽  
pp. 135-136 ◽  
Author(s):  
Diane S. Wong ◽  
James M. Cordes ◽  
Shami Chatterjee ◽  
Ellen G. Zweibel ◽  
John P. Finley ◽  
...  
Keyword(s):  
Proper Motion ◽  
Hot Spot ◽  
Optical Emission ◽  
Position Angle ◽  
Bow Shock ◽  
Radio Pulsar ◽  
X Ray ◽  
Multi Wavelength ◽  
Pulsar Wind

As part of a multi-wavelength study, we report on a 50 ks Chandra/ACIS observation of the Guitar Nebula, a bow shock nebula associated with the radio pulsar B2224+65. We see a “hot spot” at the tip of the bow shock. We also notice a “jet” of X-ray emission at position angle (PA) −69°. However, the proper motion of the pulsar and the axis of optical emission is at PA 52°.1. We discuss the resulting interpretations of the relativistic pulsar wind and the surrounding ISM.

scholarly journals Radio Polarimetry Results for Young Southern Pulsars

2000 ◽  
Vol 177 ◽  
pp. 247-248
Author(s):  
Fronefield Crawford ◽  
Victoria M. Kaspi ◽  
Richard N. Manchester
Keyword(s):  
High Spin ◽  
Inclination Angle ◽  
Linear Polarization ◽  
Position Angle ◽  
Recent Model ◽  
Vector Model ◽  
Pulsar Magnetosphere ◽  
X Ray ◽  
Magnetic Inclination ◽  
Angle Data

AbstractWe present radio polarimetry results for nine Southern pulsars. Six of the nine are young, with characteristic ages less than 100 kyr and high spin-down luminosities. All six show significant linear polarization, and we confirm a previously noticed trend in which the degree of linear polarization increases with spin-down luminosity. We have used the rotating vector model to fit the observed position angle data for PSR J1513–5908 (B1509–58). We find that a magnetic inclination angleα> 60° is excluded at the 3σlevel in the fit, and that the geometry suggested by the morphology of an apparent bipolar X-ray outflow is marginally inconsistent with a recent model of the pulsar magnetosphere.

scholarly journals The superslow pulsation X-ray pulsars in high mass X-ray binaries

2012 ◽  
Vol 8 (S291) ◽  
pp. 203-206 ◽  
Author(s):  
Wei Wang
Keyword(s):  
Neutron Star ◽  
Binary Systems ◽  
High Mass ◽  
X Ray ◽  
Origin And Evolution ◽  
Surface Magnetic Field ◽  
Spin Period ◽  
Binary Evolution ◽  
X Ray Binaries

AbstractThere exists a special class of X-ray pulsars that exhibit very slow pulsation of Pspin > 1000 s in the high mass X-ray binaries (HMXBs). We have studied the temporal and spectral properties of these superslow pulsation neutron star binaries in hard X-ray bands with INTEGRAL observations. Long-term monitoring observations find spin period evolution of two sources: spin-down trend for 4U 2206+54 (Pspin ~ 5560 s with Ṗspin ~ 4.9 × 10−7 s s−1) and long-term spin-up trend for 2S 0114+65 (Pspin ~ 9600 s with Ṗspin ~ −1 × 10−6 s s−1) in the last 20 years. A Be X-ray transient, SXP 1062 (Pspin ~ 1062 s), also showed a fast spin-down rate of Ṗspin ~ 3 × 10−6 s s−1 during an outburst. These superslow pulsation neutron stars cannot be produced in the standard X-ray binary evolution model unless the neutron star has a much stronger surface magnetic field (B > 1014 G). The physical origin of the superslow spin period is still unclear. The possible origin and evolution channels of the superslow pulsation X-ray pulsars are discussed. Superslow pulsation X-ray pulsars could be younger X-ray binary systems, still in the fast evolution phase preceding the final equilibrium state. Alternatively, they could be a new class of neutron star system – accreting magnetars.

scholarly journals Microsecond polarimetry of the repeating FRB 20180916B

2020 ◽  
Author(s):  
Kenzie Nimmo ◽  
Jason Hessels ◽  
Aard Keimpema ◽  
Anne Archibald ◽  
James Cordes ◽  
...  
Keyword(s):  
Time Resolution ◽  
Position Angle ◽  
High Time ◽  
Dispersion Measure ◽  
High Time Resolution ◽  
Radio Bursts ◽  
Signal To Noise ◽  
Propagation Effects ◽  
Local Medium ◽  
Very High

Abstract Fast radio bursts (FRBs) exhibit a wide variety of spectral, temporal and polarimetric properties, which can unveil clues into their emission physics and propagation effects in the local medium. FRBs are challenging to study at very high time resolution due to the precision needed to constrain the dispersion measure, signal-to-noise limitations, and also scattering from the intervening medium. Here we present the high-time-resolution (down to 1 μs) polarimetric properties of four 1.7-GHz bursts from the repeating FRB 20180916B, which were detected in voltage data during observations with the European VLBI Network. In these bursts we observe a range of emission timescales spanning three orders of magnitude, the shortest component width reaching 3-4 μs (below which we are limited by scattering). We demonstrate that all four bursts are highly linearly polarised (≥ 80%), show no evidence for significant circular polarisation (≤ 15%), and exhibit a constant polarisation position angle during and between bursts. On short timescales (≤ 100 μs), however, there appear to be subtle (few degree) polarisation position angle variations across the burst profiles. These observational results are most naturally explained in an FRB model where the emission is magnetospheric in origin, as opposed to models where the emission originates at larger distances in a relativistic shock.

scholarly journals Repeating fast radio bursts with WSRT/Apertif

2020 ◽  
Vol 635 ◽  
pp. A61 ◽  
Author(s):  
L. C. Oostrum ◽  
Y. Maan ◽  
J. van Leeuwen ◽  
L. Connor ◽  
E. Petroff ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Extended Period ◽  
Position Angle ◽  
Host Galaxy ◽  
Dispersion Measure ◽  
Radio Bursts ◽  
Emission Mechanism ◽  
Feed System ◽  
Arrival Times ◽  
Linear Polarisation

Context. Repeating fast radio bursts (FRBs) present excellent opportunities to identify FRB progenitors and host environments as well as to decipher the underlying emission mechanism. Detailed studies of repeating FRBs might also hold clues as to the origin of FRBs as a population. Aims. We aim to detect bursts from the first two repeating FRBs, FRB 121102 (R1) and FRB 180814.J0422+73 (R2), and to characterise their repeat statistics. We also want to significantly improve the sky localisation of R2 and identify its host galaxy. Methods. We used the Westerbork Synthesis Radio Telescope to conduct extensive follow-up of these two repeating FRBs. The new phased-array feed system, Apertif, allows one to cover the entire sky position uncertainty of R2 with fine spatial resolution in a single pointing. The data were searched for bursts around the known dispersion measures of the two sources. We characterise the energy distribution and the clustering of detected R1 bursts. Results. We detected 30 bursts from R1. The non-Poissonian nature is clearly evident from the burst arrival times, which is consistent with earlier claims. Our measurements indicate a dispersion measure (DM) of 563.5(2) pc cm−3, suggesting a significant increase in DM over the past few years. Assuming a constant position angle across the burst, we place an upper limit of 8% on the linear polarisation fraction for the brightest burst in our sample. We did not detect any bursts from R2. Conclusions. A single power-law might not fit the R1 burst energy distribution across the full energy range or widely separated detections. Our observations provide improved constraints on the clustering of R1 bursts. Our stringent upper limits on the linear polarisation fraction imply a significant depolarisation, either intrinsic to the emission mechanism or caused by the intervening medium at 1400 MHz, which is not observed at higher frequencies. The non-detection of any bursts from R2, despite nearly 300 h of observations, implies either a highly clustered nature of the bursts, a steep spectral index, or a combination of the two assuming that the source is still active. Another possibility is that R2 has turned off completely, either permanently or for an extended period of time.

THE SATURATED MAGNETIC FIELD OF THE NEUTRON STARS

2000 ◽  
Vol 09 (01) ◽  
pp. 1-12 ◽  
Author(s):  
C. M. ZHANG
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Neutron Star ◽  
Neutron Stars ◽  
Thermal Effect ◽  
X Ray ◽  
Surface Magnetic Field ◽  
Spin Period ◽  
Field Versus ◽  
The Magnetic Field

Considering the ferromagnetic screening for the decay of the X-ray neutron star magnetic field in the binary accretion phase, the phase transition of ferromagnetic materials in the crust of neutron star induces the ferromagnetic screening saturation of the accreted crust, which results in the minimum surface magnetic field of the accreting neutron star, about 108 G, if the accreted matter has completely replaced the crust mass of the neutron star. The magnetic field evolution versus accreted mass is given as [Formula: see text], and the obtained magnetic field versus spin period relation is consistent with the distribution of the binary X-ray sources and recycled pulsars. The further thermal effect on the magnetic evolution is also studied.

scholarly journals Empirical estimates of the Galactic halo contribution to the dispersion measures of extragalactic fast radio bursts using X-ray absorption

2020 ◽  
Vol 500 (1) ◽  
pp. 655-662
Author(s):  
Sanskriti Das ◽  
Smita Mathur ◽  
Anjali Gupta ◽  
Fabrizio Nicastro ◽  
Yair Krongold
Keyword(s):  
Galactic Halo ◽  
Dispersion Measure ◽  
Radio Bursts ◽  
X Ray ◽  
Empirical Estimates ◽  
The Galaxy ◽  
Dispersion Measures ◽  
Baryonic Mass ◽  
X Ray Absorption ◽  
Galactic Longitude

ABSTRACT We provide an empirical list of the Galactic dispersion measure (DMGal) contribution to the extragalactic fast radio bursts (FRBs) along 72 sightlines. It is independent of any model of the Galaxy, i.e. we do not assume the density of the disc or the halo, spatial extent of the halo, baryonic mass content, or any such external constraints to measure DMGal. We use 21-cm, UV, EUV, and X-ray data to account for different phases, and find that DMGal is dominated by the hot phase probed by X-ray absorption. We improve upon the measurements of N($\rm{O}\,{\small VII}$) and f$_{\rm O\,{\small VII}}$ compared to previous studies, thus providing a better estimate of the hot phase contribution. The median DMGal = 64$^{+20}_{-23}$ cm−3 pc, with a 68 per cent (90 per cent) confidence interval of 33–172 (23–660) cm−3 pc. The DMGal does not appear to follow any trend with the Galactic longitude or latitude, and there is a large scatter around the values predicted by simple disc + spherical halo models. Our measurements provide more complete and accurate estimates of DMGal independent from the previous studies. We provide a table and a code to retrieve DMGal for any FRB localized in the sky.

scholarly journals Exploring the dispersion measure of the Milky Way halo

2020 ◽  
Vol 496 (1) ◽  
pp. L106-L110 ◽  
Author(s):  
Laura C Keating ◽  
Ue-Li Pen
Keyword(s):  
Milky Way ◽  
External Pressure ◽  
Dispersion Measure ◽  
Radio Bursts ◽  
X Ray ◽  
Additional Information ◽  
Order Of Magnitude ◽  
Dispersion Measures ◽  
Extreme Model ◽  
Milky Way Halo

Abstract Fast radio bursts offer the opportunity to place new constraints on the mass and density profile of hot and ionized gas in galactic haloes. We test here the X-ray emission and dispersion measure predicted by different gas profiles for the halo of the Milky Way. We examine a range of models, including entropy stability conditions and external pressure continuity. We find that incorporating constraints from X-ray observations leads to favouring dispersion measures on the lower end of the range given by these models. We show that the dispersion measure of the Milky Way halo could be less than 10 cm−3 pc in the most extreme model we consider, which is based on constraints from O vii absorption lines. However, the models allowed by the soft X-ray constraints span more than an order of magnitude in dispersion measures. Additional information on the distribution of gas in the Milky Way halo could be obtained from the signature of a dipole in the dispersion measure of fast radio bursts across the sky, but this will be a small effect for most cases.

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

2000 ◽  
Vol 177 ◽  
pp. 349-350
Author(s):  
M. J. Pivovaroff ◽  
V. M. Kaspi ◽  
F. Camilo
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
High Magnetic Field ◽  
Radio Pulsar ◽  
X Ray ◽  
Surface Magnetic Field ◽  
Flux Limit ◽  
Dipole Magnetic Field ◽  
Surface Dipole

AbstractWe present X-ray observations of PSR J1814–1744, a 4 s radio pulsar with inferred surface dipole magnetic field strength 5.5 × 1013G recently discovered in the on-going Parkes multibeam survey. This pulsar’s spin parameters are very similar to those of anomalous X-ray pulsars (AXPs). X-ray emission is not detected from the position of the radio pulsar in observations withROSATandASCA. The derived upper flux limit implies an X-ray luminosity significantly smaller than those of all known AXPs. These results argue that magnetar mechanism invoked to explain X-ray emission from AXPs must depend on more than merely the inferred surface magnetic field strength as estimated fromPand.

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