- ID:
- ivo://CDS.VizieR/J/A+A/445/243
- Title:
- Pulsar subpulse modulation properties at 21cm
- Short Name:
- J/A+A/445/243
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a systematic, unbiased search for subpulse modulation of 187 pulsars performed with the Westerbork Synthesis Radio Telescope (WSRT) in the Netherlands at an observing wavelength of 21cm. Using new observations and archival WSRT data we have increased the list of pulsars that show the drifting subpulse phenomenon by 42, indicating that at least one in three pulsars exhibits this phenomenon. The real fraction of pulsars that show the drifting phenomenon is likely to be larger than 55%. The majority of the analysed pulsars show subpulse modulation (170), of which the majority were not previously known to show subpulse modulation and 30 show clear systematic drifting. The large number of new drifters we have found allows us, for the first time, to do meaningful statistics on the drifting phenomenon.
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112. Pulsar timing at UAO
- ID:
- ivo://CDS.VizieR/J/MNRAS/328/855
- Title:
- Pulsar timing at UAO
- Short Name:
- J/MNRAS/328/855
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A pulsar timing system has been operating in the 18-cm band at the Urumqi Astronomical Observatory 25-m telescope since mid-1999. Frequency resolution allowing de-dispersion of the pulsar signals is provided by a 2x128x2.5MHz filterbank/digitizer system. Observations of 74 pulsars over more than 12 months have resulted in updated pulsar periods and period derivatives, as well as improved positions. Comparison with previous measurements showed that the changes in period and period derivative tend to have the same sign and to be correlated in amplitude. A model based on unseen glitches gives a good explanation of the observed changes, suggesting that long-term fluctuations in period and period derivatives are dominated by glitches. In 2000 July, we detected a glitch of relative amplitude {Delta}{nu}/{nu}~24x10^-9^in the Crab pulsar. The post-glitch decay appears similar to other large Crab glitches.
- ID:
- ivo://CDS.VizieR/J/A+A/492/923
- Title:
- Pulsar Timing for Fermi Gamma-ray Space Telescope
- Short Name:
- J/A+A/492/923
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a comprehensive pulsar monitoring campaign for the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (formerly GLAST). The detection and study of pulsars in gamma rays give insights into the populations of neutron stars and supernova rates in the Galaxy, into particle acceleration mechanisms in neutron star magnetospheres, and into the "engines" driving pulsar wind nebulae. LAT's unprecedented sensitivity between 20MeV and 300GeV together with its 2.4sr field-of-view makes detection of many gamma-ray pulsars likely, justifying the monitoring of over two hundred pulsars with large spin-down powers. To search for gamma-ray pulsations from most of these pulsars requires a set of phase-connected timing solutions spanning a year or more to properly align the sparse photon arrival times. We describe the choice of pulsars and the instruments involved in the campaign.
- ID:
- ivo://CDS.VizieR/J/A+A/586/A92
- Title:
- Pulse profiles of 100 radio pulsars
- Short Name:
- J/A+A/586/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- LOFAR offers the unique capability of observing pulsars across the 10-240MHz frequency range with a fractional bandwidth of roughly 50%. This spectral range is well suited for studying the frequency evolution of pulse profile morphology caused by both intrinsic and extrinsic effects such as changing emission altitude in the pulsar magnetosphere or scatter broadening by the interstellar medium, respectively. The magnitude of most of these effects increases rapidly towards low frequencies. LOFAR can thus address a number of open questions about the nature of radio pulsar emission and its propagation through the interstellar medium. We present the average pulse profiles of 100 pulsars observed in the two LOFAR frequency bands: high band (120-167MHz, 100 profiles) and low band (15-62MHz, 26 profiles). We compare them with Westerbork Synthesis Radio Telescope (WSRT) and Lovell Telescope observations at higher frequencies (350 and 1400MHz) to study the profile evolution. The profiles were aligned in absolute phase by folding with a new set of timing solutions from the Lovell Telescope, which we present along with precise dispersion measures obtained with LOFAR. We find that the profile evolution with decreasing radio frequency does not follow a specific trend; depending on the geometry of the pulsar, new components can enter into or be hidden from view. Nonetheless, in general our observations confirm the widening of pulsar profiles at low frequencies, as expected from radius-to-frequency mapping or birefringence theories.
- ID:
- ivo://CDS.VizieR/J/AZh/87/238
- Title:
- Pulse profiles of radio pulsars at 102 and 111MHz
- Short Name:
- J/AZh/87/238
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Average profiles for 180, mostly faint, pulsars at 102 and 111MHz are presented. Pulse shapes have been obtained for the first time for most of the faint pulsars (about 50% of the total sample). A comparison with high-frequency data (mostly at 234, 408, 610, 925, and 1408MHz) demonstrates appreciable changes in the profile width and shape with frequency. For most pulsars, the number of components is preserved, but the intensities of individual components can change. As a rule, the profile width increases with decreasing frequency. The possible generation of emission at the cyclotron frequencies is considered.
- ID:
- ivo://CDS.VizieR/J/A+A/402/647
- Title:
- Pulse-time history of PSR B0540-69
- Short Name:
- J/A+A/402/647
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A pulse-time history of PSR B0540-69 is reported, based on the analysis of an extended data set including ASCA, BeppoSAX and RXTE observations spanning a time interval of about 8 years. This interval includes also the epoch of the glitch episode reported by Zhang et al. (2001ApJ...554L.177Z). The log of all observations include: RXTE observations between 1996-03-08 and 2001-03-14: data from PCA only, accumulated in "Good Xenon" telemetry mode, time-tagged with a 1us accuracy; ASCA observations between 1993-06-13 and 1999-11-03: data from GIS Beppo-SAX observations between 1996-10-26 and 2000-02-19: data from MECS
- ID:
- ivo://CDS.VizieR/J/A+A/366/565
- Title:
- Radial oscillations of relativistic stars
- Short Name:
- J/A+A/366/565
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new survey of the radial oscillation modes of neutron stars. This study complements and corrects earlier studies of radial oscillations. We present an extensive list of frequencies for the most common equations of state and some more recent ones. In order to check the accuracy, we use two different numerical schemes which yield the same results. The stimulation for this work comes from the need of the groups that evolve the full nonlinear Einstein equations to have reliable results from perturbation theory for comparison.
- ID:
- ivo://CDS.VizieR/J/ApJ/716/L109
- Title:
- Radio and X-ray observations of Aql X-1
- Short Name:
- J/ApJ/716/L109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 2009 November outburst of the neutron star X-ray binary Aquila X-1 (Aql X-1) was observed with unprecedented radio coverage and simultaneous pointed X-ray observations, tracing the radio emission around the full X-ray hysteresis loop of the outburst for the first time. We use these data to discuss the disk-jet coupling, finding the radio emission to be consistent with being triggered at state transitions, both from the hard to the soft spectral state and vice versa. Our data appear to confirm previous suggestions of radio quenching in the soft state above a threshold X-ray luminosity of ~10% of the Eddington luminosity. We also present the first detections of Aql X-1 with very long baseline interferometry, showing that any extended emission is relatively diffuse and consistent with steady jets rather than arising from discrete, compact knots. In all cases where multi-frequency data were available, the source radio spectrum is consistent with being flat or slightly inverted, suggesting that the internal shock mechanism that is believed to produce optically thin transient radio ejecta in black hole X-ray binaries is not active in Aql X-1.
- ID:
- ivo://CDS.VizieR/J/AZh/79/501
- Title:
- Radio luminosities of normal & millisecond pulsars
- Short Name:
- J/AZh/79/501
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of comparative statistical analysis of the integrated radio luminosities of normal and millisecond pulsars are presented. The analysis is based on our own measurements of the flux densities, spectra and integrated radio luminosities of the millisecond pulsars., as well as data from the literature used to determine the integrated radio luminosities for 545 pulsars.
- ID:
- ivo://CDS.VizieR/J/AZh/71/762
- Title:
- Radio luminosities of 232 pulsars
- Short Name:
- J/AZh/71/762
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Total radio luminosities of 232 pulsars are calculated using new data on mean spectra. For 88% of these pulsars, luminosities lie in the range 10^27^-10^30^erg/s. It is shown that pulsar luminosity remains constant over a period of a few million years. Mean radiation power increases with period P as P^0.5^. An increase in luminosity with the rotational energy loss rate is found.
