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71. 327MHz observations of 124 pulsars
ID:
ivo://CDS.VizieR/J/ApJ/804/23
Title:
327MHz observations of 124 pulsars
Short Name:
J/ApJ/804/23
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the measurements of scatter broadening timescales ({tau}_SC_) for 124 pulsars at 327MHz using the upgraded Ooty Radio Telescope (ORT). These pulsars lie in the dispersion measure range of 37-503pc/cm3 and declination ({delta}) range of -57{deg}<{sigma}<60{deg}. New {tau}_SC_ estimates for 58 pulsars are presented, increasing the sample of all such measurements by about 40% at 327MHz. Using all available {tau}_SC_ measurements in the literature, we investigate the dependence of {tau}_SC_ on dispersion measure. Our measurements, together with previously reported values for {tau}_SC_, affirm that the ionized interstellar medium up to 3kpc is consistent with the Kolmogorov spectrum, while it deviates significantly beyond this distance.
72. 115-155MHz radio survey of Fermi sources
ID:
ivo://CDS.VizieR/J/ApJ/846/L19
Title:
115-155MHz radio survey of Fermi sources
Short Name:
J/ApJ/846/L19
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using LOFAR, we have performed a very-low-frequency (115-155MHz) radio survey for millisecond pulsars (MSPs). The survey targeted 52 unidentified Fermi {gamma}-ray sources. Employing a combination of coherent and incoherent dedispersion, we have mitigated the dispersive effects of the interstellar medium while maintaining sensitivity to fast-spinning pulsars. Toward 3FGLJ1553.1+5437 we have found PSRJ1552+5437, the first MSP to be discovered (through its pulsations) at a radio frequency <200MHz. PSR J1552+5437 is an isolated MSP with a 2.43ms spin period and a dispersion measure of 22.9pc/cm^3^. The pulsar has a very steep radio spectral index ({alpha}-2.8+/-0.4). We obtain a phase-connected timing solution combining the 0.74yr of radio observations with {gamma}-ray photon arrival times covering 7.5yr of Fermi observations. We find that the radio and {gamma}-ray pulse profiles of PSR J1552+5437 appear to be nearly aligned. The very steep spectrum of PSR J1552+5437, along with other recent discoveries, hints at a population of radio MSPs that have been missed in surveys using higher observing frequencies. Detecting such steep spectrum sources is important for mapping the population of MSPs down to the shortest spin periods, understanding their emission in comparison to slow pulsars, and quantifying the prospects for future surveys with low-frequency radio telescopes like SKA-Low and its precursors.
73. 42 millisecond pulsars high-precision timing
ID:
ivo://CDS.VizieR/J/MNRAS/458/3341
Title:
42 millisecond pulsars high-precision timing
Short Name:
J/MNRAS/458/3341
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on the high-precision timing of 42 radio millisecond pulsars (MSPs) observed by the European Pulsar Timing Array (EPTA). This EPTA Data Release 1.0 extends up to mid-2014 and baselines range from 7-18yr. It forms the basis for the stochastic gravitational-wave background, anisotropic background, and continuous-wave limits recently presented by the EPTA elsewhere. The Bayesian timing analysis performed with TEMPONEST yields the detection of several new parameters: seven parallaxes, nine proper motions and, in the case of six binary pulsars, an apparent change of the semimajor axis. We find the NE2001 Galactic electron density model to be a better match to our parallax distances (after correction from the Lutz-Kelker bias) than the M2 and M3 models by Schnitzeler. However, we measure an average uncertainty of 80 per cent (fractional) for NE2001, three times larger than what is typically assumed in the literature. We revisit the transverse velocity distribution for a set of 19 isolated and 57 binary MSPs and find no statistical difference between these two populations. We detect Shapiro delay in the timing residuals of PSRs J1600-3053 and J1918-0642, implying pulsar and companion masses mp=1.22^+0.5^_-0.35_M_{sun}_, mc=0.21^+0.06^_-0.04_M_{sun}_ and mp=1.25^+0.6^_-0.4_M_{sun}}, mc=0.23^+0.07^_-0.05_M_{sun}_, respectively. Finally, we use the measurement of the orbital period derivative to set a stringent constraint on the distance to PSRs J1012+5307 and J1909-3744, and set limits on the longitude of ascending node through the search of the annual-orbital parallax for PSRs J1600-3053 and J1909-3744.
74. Multifrequency fluxes of 280 pulsars
ID:
ivo://CDS.VizieR/J/MNRAS/273/411
Title:
Multifrequency fluxes of 280 pulsars
Short Name:
J/MNRAS/273/411
Date:
21 Oct 2021
Publisher:
CDS
Description:
Table3 contains the flux density measurements of pulsars made at radio frequencies centred around 408, 606, 925, 1408 and 1606MHz using the 76-m Lowell telescope at Jodrell Bank. The observations have been made over a period of more than 3 years and concern 280 pulsars.
75. Multifrequency obs. of radio pulse broadening
ID:
ivo://CDS.VizieR/J/ApJ/605/759
Title:
Multifrequency obs. of radio pulse broadening
Short Name:
J/ApJ/605/759
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have made observations of 98 low Galactic latitude pulsars to measure pulse broadening caused by multipath propagation through the interstellar medium. Data were collected with the 305m Arecibo telescope at four radio frequencies between 430 and 2380MHz. We used a CLEAN-based algorithm to deconvolve interstellar pulse broadening from the measured pulse shapes. We employed two distinct pulse-broadening functions (PBFs): PBF_1_ is appropriate for a thin screen of scattering material between the Earth and a pulsar, while PBF_2_ is appropriate for scattering material uniformly distributed along the line of sight from the Earth to a pulsar. We found that some observations were better fitted by PBF_1_ and some by PBF_2_. Pulse-broadening times ({tau}_d_) are derived from fits of PBFs to the data and are compared with the predictions of a smoothed model of the Galactic electron distribution. Several lines of sight show excess broadening, which we model as clumps of high-density scattering material.
76. Multifrequency polarimetry of 300 pulsars
ID:
ivo://CDS.VizieR/J/MNRAS/301/235
Title:
Multifrequency polarimetry of 300 pulsars
Short Name:
J/MNRAS/301/235
Date:
21 Oct 2021
Publisher:
CDS
Description:
Polarimetric observations of 300 pulsars have been conducted with the 76-m Lovell telescope at Jodrell Bank at radio frequencies centred around 230, 400, 600, 920, 1400 and 1600MHz. More than half of the pulsars have no previously published polarization profiles and this compilation represents about three times the sum of all previously published pulsar polarization data. A selection of integrated polarization profiles is provided. Tables of pulse widths and the degree of both linear and circular polarization are given for all pulsars, and these act as an index for all the data, which are available by anonymous ftp in numerical and graphical form.
77. Multifrequency pulsar scatter time sample
ID:
ivo://CDS.VizieR/J/MNRAS/449/1570
Title:
Multifrequency pulsar scatter time sample
Short Name:
J/MNRAS/449/1570
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present our results of pulse broadening time estimates and the study of the frequency scaling of this quantity for 60 pulsars based on actual multifrequency scattering estimates. This research was based on our own measurements, performed on the observational data and the profiles from various pulsar profile data bases, as well as the scatter time measurements that were found in the literature. We were able to construct a data base of over 60 pulsars with true multifrequency {alpha} measurements, which allowed us to revise the previously proposed relations between the scatter time spectral slope and the dispersion measure (DM). We found that the deviations from theoretical predictions of the value of {alpha} appear for pulsars regardless of their DM, however, the DM-averaged value of the scaling index is almost constant except for pulsars with very high DMs. Based on the obtained slopes we were also able to estimate the amount of scattering at the standard frequency of 1GHz. We found that while the estimated standardized pulse broadening time increases with DM the relation seems to be much flatter than it was previously proposed, which suggests higher values of the scatter time for mid-DM pulsars, and lower values of expected pulse broadening for highly dispersed sources.
78. 2nd Fermi LAT cat. of gamma-ray pulsars (2PC)
ID:
ivo://CDS.VizieR/J/ApJS/208/17
Title:
2nd Fermi LAT cat. of gamma-ray pulsars (2PC)
Short Name:
J/ApJS/208/17
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalog summarizes 117 high-confidence >= 0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions.
79. Neutron star properties with unified EoS
ID:
ivo://CDS.VizieR/J/A+A/559/A128
Title:
Neutron star properties with unified EoS
Short Name:
J/A+A/559/A128
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the global properties of neutron stars obtained with the Brussels-Montreal equations of state (EoSs). These EoSs, which provide a unified description of all regions of a neutron star, are based on the generalised Skyrme functionals BSk19, BSk20, and BSk21. The neutron-star properties thus obtained are compared with various astrophysical observations. We find that only the stiffest EoS, based on the functional BSk21, is at least marginally compatible with all the constraints inferred from these observations.
80. Neutron stars in NGC 5139
ID:
ivo://CDS.VizieR/J/ApJ/578/405
Title:
Neutron stars in NGC 5139
Short Name:
J/ApJ/578/405
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Chandra/ACIS-I detectors observed NGC 5139 in imaging mode for two continuous periods (2000 January 24 02:15-09:46 and January 25 04:33-17:24 TT) for a total exposure of ~68.6ks. We combined the two observations and analyzed them as one. We searched for point sources using CELLDETECT, using only the 0.1-2.5keV energy range, excluding regions less than 16 pixels from the detector edges and keeping only sources with signal-to-noise ratio (S/N)>5.0. We find 40 X-ray point sources over the four ACIS-I chips and chip S2 of ACIS-S, which are numbered in order of decreasing S/N in Table 1.