General Relativistic Precession of the Spin Axis of Binary Pulsar B1913+16: First Two Dimensional Maps of the Emission Beam

2000 ◽  
Vol 177 ◽  
pp. 127-130 ◽  
Author(s):  
Joel M. Weisberg ◽  
Joseph H. Taylor
Keyword(s):  
Intensity Ratio ◽  
Two Dimensions ◽  
Spin Axis ◽  
Secular Change ◽  
Line Of Sight ◽  
Pulse Profile ◽  
Binary Pulsar ◽  
Secular Evolution ◽  
General Relativistic ◽  
Emission Beam

AbstractRelativistic spin-orbit coupling should cause the spin axis of Binary Pulsar B1913+16 to precess at a rate of about 1 deg / yr. As a result, the pulse profile is expected to exhibit secular evolution. Weisberg, Romani, & Taylor (1989), and Weisberg & Taylor (1992) found that the intensity ratio of the two conal components changed at a one percent per year rate from 1981 to 1989, but that their spacing did not measurably change. They attributed these observations to our line of sight passing across the middle of a patchy cone of emission. Recently Kramer (1998) found that the intensity ratio continued its secular change for another decade, and also detected a narrowing of the conal component separation.We present our analysis of eighteen years of 21 cm pulse profile data. We confirm that the profile is narrowing as precession finally carries our line of sight away from the emission beam axis, and we map the beam in two dimensions. The beam is elongated in the latitude direction, and the degree of elongation grows with radius.

scholarly journals Profile Changes in the Binary Pulsar PSR 1913+16

1992 ◽  
Vol 128 ◽  
pp. 214-216
Author(s):  
J. M. Weisberg ◽  
J. H. Taylor
Keyword(s):  
General Relativity ◽  
Flux Density ◽  
Spin Axis ◽  
Line Of Sight ◽  
Emission Region ◽  
Pulse Profile ◽  
Pulsar Emission ◽  
Binary Pulsar ◽  
The Past ◽  
Profile Changes

AbstractAccording to general relativity, the spin axis of binary pulsar PSR 1913+16 should precess at a rate of 1.21 degrees per year. This precession will cause the pulse profile to change as our line of sight samples different pulsar latitudes. In order to search for this phenomenon, we have carefully monitored the pulse profile at 1408 MHz for 8.5 years. The ratio of flux density of the first to second pulse component has declined at a rate of approximately 1.65% per year, with some evidence of a steeper decrease over the past three years. We have detected no evidence for a change in the separation of the two components. We discuss the nature of the pulsar emission region in light of these results.

scholarly journals Recent Observations of PSR B1534+12

2001 ◽  
Vol 205 ◽  
pp. 408-409
Author(s):  
I.H. Stairs ◽  
S.E. Thorsett ◽  
J.H. Taylor ◽  
Z. Arzoumanian
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Spin Axis ◽  
Pulse Profile ◽  
High Quality ◽  
Orbital Parameters ◽  
General Relativistic ◽  
Star Binary

We present the results of recent Arecibo observations of the relativistic double-neutron-star binary PSR B1534+12. The timing solution includes measurements of five post-Keplerian orbital parameters, whose values agree well with the predictions of general relativity. The observations show that the pulse profile is evolving secularly at both 1400 MHz and 430 MHz. This effect is similar to that seen in PSR B1913+16, and is almost certainly due to general relativistic precession of the pulsar's spin axis. We also present high-quality polarimetric profiles at both observing frequencies.

scholarly journals High-cadence observations and variable spin behaviour of magnetar Swift J1818.0−1607 after its outburst

2020 ◽  
Vol 498 (4) ◽  
pp. 6044-6056
Author(s):  
David Champion ◽  
Ismael Cognard ◽  
Marilyn Cruces ◽  
Gregory Desvignes ◽  
Fabian Jankowski ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Position Angle ◽  
Spectral Information ◽  
Line Of Sight ◽  
Radio Observations ◽  
Pulse Profile ◽  
Variable Spin ◽  
Order Of Magnitude ◽  
Emission Beam ◽  
High Cadence

ABSTRACT We report on multifrequency radio observations of the new magnetar Swift J1818.0−1607, following it for more than one month with high cadence. The observations commenced less than 35 h after its registered first outburst. We obtained timing, polarization, and spectral information. Swift J1818.0−1607 has an unusually steep spectrum for a radio emitting magnetar and also has a relatively narrow and simple pulse profile. The position angle swing of the polarization is flat over the pulse profile, possibly suggesting that our line of sight grazes the edge of the emission beam. This may also explain the steep spectrum. The spin evolution shows large variation in the spin-down rate, associated with four distinct timing events over the course of our observations. Those events may be related to the appearance and disappearance of a second pulse component. The first timing event coincides with our actual observations, while we did not detect significant changes in the emission properties that could reveal further magnetospheric changes. Characteristic ages inferred from the timing measurements over the course of months vary by nearly an order of magnitude. A longer-term spin-down measurement over approximately 100 d suggests a characteristic age of about 500 yr, larger than previously reported. Though Swift J1818.0−1607 could still be one of the youngest neutron stars (and magnetars) detected so far, we caution using the characteristic age as a true-age indicator given the caveats behind its calculation.

scholarly journals Geodetic Precession in PSR B1534+12

2000 ◽  
Vol 177 ◽  
pp. 121-124 ◽  
Author(s):  
I. H. Stairs ◽  
S. E. Thorsett ◽  
J. H. Taylor ◽  
Z. Arzoumanian
Keyword(s):  
Spin Axis ◽  
Pulse Profile ◽  
Geodetic Precession ◽  
General Relativistic

AbstractWe present Arecibo observations of PSR B1534+12 which confirm previous suggestions that the pulse profile is evolving secularly. This effect is similar to that seen in PSR B1913+16, and is almost certainly due to general relativistic precession of the pulsar’s spin axis.

scholarly journals The VMC survey

2018 ◽  
Vol 613 ◽  
pp. L8 ◽  
Author(s):  
F. Niederhofer ◽  
M.-R. L. Cioni ◽  
S. Rubele ◽  
T. Schmidt ◽  
K. Bekki ◽  
...  
Keyword(s):  
Near Infrared ◽  
Two Dimensions ◽  
Magellanic Clouds ◽  
Line Of Sight ◽  
Main Body ◽  
Proper Motions ◽  
Velocity Pattern ◽  
Spatially Resolved ◽  
Magnitude Diagram ◽  
Over Time

We present the first spatially resolved map of stellar proper motions within the central (~3.1 × 2.4 kpc) regions of the Small Magellanic Cloud (SMC). The data used for this study encompasses four tiles from the ongoing near-infrared VISTA survey of the Magellanic Clouds system and covers a total contiguous area on the sky of ~6.81 deg2. Proper motions have been calculated independently in two dimensions from the spatial offsets in the Ks filter over time baselines between 22 and 27 months. The reflex motions of approximately 33 000 background galaxies are used to calibrate the stellar motions to an absolute scale. The resulting catalog is composed of more than 690 000 stars which have been selected based on their position in the (J − Ks, Ks) color-magnitude diagram. For the median absolute proper motion of the SMC, we find (μαcos(δ), μδ) = (1.087 ± 0.192 (sys.) ± 0.003 (stat.), −1.187 ± 0.008 (sys.) ± 0.003 (stat.)) mas yr−1, consistent with previous studies. Mapping the proper motions as a function of position within the SMC reveals a nonuniform velocity pattern indicative of a tidal feature behind the main body of the SMC and a flow of stars in the south-east moving predominantly along the line-of-sight.

scholarly journals Long-term observations of pulsars in the globular clusters 47 Tucanae and M15

2017 ◽  
Vol 13 (S337) ◽  
pp. 251-254
Author(s):  
A. Ridolfi ◽  
P. C. C. Freire ◽  
M. Kramer ◽  
C. G. Bassa ◽  
F. Camilo ◽  
...  
Keyword(s):  
Gravitational Potential ◽  
Globular Clusters ◽  
Higher Order ◽  
The Other ◽  
Line Of Sight ◽  
Physical Parameters ◽  
Spin Period ◽  
Emission Beam ◽  
System Geometry

AbstractMulti-decade observing campaigns of the globular clusters 47 Tucanae and M15 have led to an outstanding number of discoveries. Here, we report on the latest results of the long-term observations of the pulsars in these two clusters. For most of the pulsars in 47 Tucanae we have measured, among other things, their higher-order spin period derivatives, which have in turn provided stringent constraints on the physical parameters of the cluster, such as its distance and gravitational potential. For M15, we have studied the relativistic spin precession effect in PSR B2127+11C. We have used full-Stokes observations to model the precession effect, and to constrain the system geometry. We find that the visible beam of the pulsar is swiftly moving away from our line of sight and may very soon become undetectable. On the other hand, we expect to see the opposite emission beam sometime between 2041 and 2053.

scholarly journals Characterization of diffuse X-ray emission from IGR J17448$-$3232: an implication of a line-of-sight merging activity

2019 ◽  
Author(s):  
Shoko Watanabe ◽  
Shigeo Yamauchi ◽  
Kumiko K Nobukawa ◽  
Hiroki Akamatsu
Keyword(s):  
Electron Temperature ◽  
Central Region ◽  
Intensity Ratio ◽  
Spectral Feature ◽  
Line Of Sight ◽  
High Electron ◽  
Plasma Model ◽  
Ionization Equilibrium ◽  
Temperature Plasma ◽  
Two Component

Abstract The results of spectral analysis for the galaxy cluster IGR J17448$-$3232 are presented. The intracluster medium (ICM) in the central region ($r\lt 300^{\prime \prime }$, $320\:$kpc) has a high electron temperature plasma of $kT_{\rm e} \sim 13$–$15\:$keV, and an ionization temperature estimated from an intensity ratio of Fe xxvi Ly$\alpha /$Fe xxv He$\alpha$ lines is lower than the electron temperature, which suggests that the ICM is in the non-ionization equilibrium (NEI) state. The spectrum in the central region can be also fitted with a two-component model: a two-temperature plasma model in a collisional ionization equilibrium (CIE) with temperatures of $7.9\:$keV and $\gt 34\:$keV, or a CIE$+$power-law model with a temperature of $9.4\:$keV and a photon index of 1.1. The two-component models can represent the intensity ratio of Fe xxvi Ly$\alpha /$Fe xxv He$\alpha$ lines. On the other hand, the spectrum in the outer region ($r\gt 300^{\prime \prime }$) can be explained by a single CIE plasma model with a temperature of 5–$8\:$keV. Based on the spectral feature and its circular structure, we propose that the NEI plasma was produced by merging along the line-of-sight direction.

scholarly journals Companion-driven evolution of massive stellar binaries

2019 ◽  
Vol 488 (2) ◽  
pp. 2480-2492 ◽  
Author(s):  
Sanaea C Rose ◽  
Smadar Naoz ◽  
Aaron M Geller
Keyword(s):  
Dynamical Evolution ◽  
Dynamical Process ◽  
Tidal Dissipation ◽  
Triple Systems ◽  
Secular Evolution ◽  
Gravitational Perturbations ◽  
Orbital Configuration ◽  
General Relativistic ◽  
X Ray Binaries ◽  
Insight Into

ABSTRACT At least $70\, {\rm per\, cent}$ of massive OBA-type stars reside in binary or higher order systems. The dynamical evolution of these systems can lend insight into the origins of extreme phenomena such as X-ray binaries and gravitational wave sources. In one such dynamical process, the Eccentric Kozai–Lidov (EKL) mechanism, a third companion star alters the secular evolution of a binary system. For dynamical stability, these triple systems must have a hierarchical configuration. We explore the effects of a distant third companion’s gravitational perturbations on a massive binary’s orbital configuration before significant stellar evolution has taken place (≤10 Myr). We include tidal dissipation and general relativistic precession. With large (38 000 total) Monte Carlo realizations of massive hierarchical triples, we characterize imprints of the birth conditions on the final orbital distributions. Specifically, we find that the final eccentricity distribution over the range of 0.1–0.7 is an excellent indicator of its birth distribution. Furthermore, we find that the period distributions have a similar mapping for wide orbits. Finally, we demonstrate that the observed period distribution for approximately 10-Myr-old massive stars is consistent with EKL evolution.

scholarly journals NADA-FLD: a general relativistic, multidimensional neutrino-hydrodynamics code employing flux-limited diffusion

2019 ◽  
Vol 490 (3) ◽  
pp. 3545-3572 ◽  
Author(s):  
N Rahman ◽  
O Just ◽  
H-T Janka
Keyword(s):  
Operator Splitting ◽  
Lateral Diffusion ◽  
Neutrino Energy ◽  
Two Dimensions ◽  
Polar Coordinates ◽  
General Relativistic ◽  
Energy Dependent ◽  
Main Effects ◽  
Limited Diffusion ◽  
Good Agreement

ABSTRACT We present the new code NADA-FLD to solve multidimensional neutrino-hydrodynamics in full general relativity (GR) in spherical polar coordinates. The energy-dependent neutrino transport assumes the flux-limited diffusion approximation and evolves the neutrino energy densities measured in the frame comoving with the fluid. Operator splitting is used to avoid multidimensional coupling of grid cells in implicit integration steps involving matrix inversions. Terms describing lateral diffusion and advection are integrated explicitly using the Allen–Cheng or the Runge–Kutta–Legendre method, which remain stable even in the optically thin regime. We discuss several toy-model problems in one and two dimensions to test the basic functionality and individual components of the transport scheme. We also perform fully dynamic core-collapse supernova (CCSN) simulations in spherical symmetry. For a Newtonian model, we find good agreement with the M1 code ALCAR, and for a GR model, we reproduce the main effects of GR in CCSNe already found by previous works.

Sign in / Sign up

Export Citation Format

Share Document