VizieR Online Data Catalog: HTRU survey: long-period pulsars polarimetry (Tiburzi+, 2013)

We present the polarization analysis of a sample of 49 long-period pulsars, whose spin periods range from a few hundred milliseconds to about two and a half seconds. They were all discovered during the mid-latitude part of the HTRU survey (Keith et al. 2010MNRAS.409..619K; Bates et al. 2012MNRAS.427.1052B) apart from PSR J1846-4249 (that has been discovered in the high latitude survey and it will be presented in one of the next papers of the HTRU series). After discovery and confirmation, the pulsars were followed-up with the third Parkes Digital Filterbank, observing them for at least one year to allow the determination of a complete timing solution. (2 data files)

VizieR Online Data Catalog: HTRU survey. Timing of 54 pulsars (Bates+, 2012)

All the pulsars presented here were discovered in the HTRU mid-latitude survey, which has now been fully processed. The survey observed the Galactic plane in the region -120°-35° were regularly observed using the 76-m Lovell Telescope and those below this declination were observed as part of the HTRU timing programme at Parkes. (3 data files)

The Sardinia Radio Telescope . From a technological project to a radio observatory

Context. The Sardinia Radio Telescope (SRT) is the new 64 m dish operated by the Italian National Institute for Astrophysics (INAF). Its active surface, comprised of 1008 separate aluminium panels supported by electromechanical actuators, will allow us to observe at frequencies of up to 116 GHz. At the moment, three receivers, one per focal position, have been installed and tested: a 7-beam K-band receiver, a mono-feed C-band receiver, and a coaxial dual-feed L/P band receiver. The SRT was officially opened in September 2013, upon completion of its technical commissioning phase. In this paper, we provide an overview of the main science drivers for the SRT, describe the main outcomes from the scientific commissioning of the telescope, and discuss a set of observations demonstrating the scientific capabilities of the SRT. Aims: The scientific commissioning phase, carried out in the 2012-2015 period, proceeded in stages following the implementation and/or fine-tuning of advanced subsystems such as the active surface, the derotator, new releases of the acquisition software, etc. One of the main objectives of scientific commissioning was the identification of deficiencies in the instrumentation and/or in the telescope subsystems for further optimization. As a result, the overall telescope performance has been significantly improved. Methods: As part of the scientific commissioning activities, different observing modes were tested and validated, and the first astronomical observations were carried out to demonstrate the science capabilities of the SRT. In addition, we developed astronomer-oriented software tools to support future observers on site. In the following, we refer to the overall scientific commissioning and software development activities as astronomical validation. Results: The astronomical validation activities were prioritized based on technical readiness and scientific impact. The highest priority was to make the SRT available for joint observations as part of European networks. As a result, the SRT started to participate (in shared-risk mode) in European VLBI Network (EVN) and Large European Array for Pulsars (LEAP) observing sessions in early 2014. The validation of single-dish operations for the suite of SRT first light receivers and backends continued in the following year, and was concluded with the first call for shared-risk early-science observations issued at the end of 2015. As discussed in the paper, the SRT capabilities were tested (and optimized when possible) for several different observing modes: imaging, spectroscopy, pulsar timing, and transients

An X-ray burst from a magnetar enlightening the mechanism of fast radio bursts

Fast radio bursts (FRBs) are millisecond radio pulses originating from powerful enigmatic sources at extragalactic distances. Neutron stars with large magnetic fields (magnetars) have been considered as the sources powering the FRBs, but the connection requires further substantiation. Here we report the detection by the AGILE satellite on 28 April 2020 of an X-ray burst in temporal coincidence with a bright FRB-like radio burst from the Galactic magnetar SGR 1935+2154. The burst observed in the hard X-ray band (18-60 keV) lasted about 0.5 s, it is spectrally cut off above 80 keV and implies an isotropically emitted energy of about 1040 erg. This event demonstrates that a magnetar can produce X-ray bursts in coincidence with FRB-like radio bursts. It also suggests that FRBs associated with magnetars can emit X-ray bursts. We discuss SGR 1935+2154 in the context of FRBs with low-intermediate radio energies in the range 1038-1040 erg. Magnetars with magnetic fields B ≈ 1015 G may power these FRBs, and new data on the search for X-ray emission from FRBs are presented. We constrain the bursting X-ray energy of the nearby FRB 180916 to be less than 1046 erg, smaller than that observed in giant flares from Galactic magnetars

The puzzling properties of the helium white dwarf orbiting the millisecond pulsar PSR J1911-5958A in NGC 6752

We have used phase-resolved high-resolution images and low-resolution spectra taken at the ESO Very Large Telescope to study the properties of the low-mass helium white dwarf companion to the millisecond pulsar PSR J1911-5958A (COM J1911-5958A), in the halo of the Galactic globular cluster NGC 6752. The radial velocity curve confirms that COM J1911-5958A is orbiting the pulsar and allows us to derive a systemic velocity of the binary system nicely in agreement with that of NGC 6752. This strongly indicates that the system is a member of the cluster, despite its very offset position (similar to 74 core radii) with respect to the core. Constraints on the orbital inclination (greater than or similar to 70 degrees) and pulsar mass (1.2-1.5 M-circle dot) are derived from the mass ratio M-PSR/M-COM = 7.49 +/- 0.64 and photometric properties of COM J1911-5958A. The light curve in the B band shows two phases of unequal brightening (Delta mag similar to 0.3 and 0.2, respectively) located close to quadratures and superimposed on an almost steady baseline emission: this feature is quite surprising and needs to be further investigated

The European Pulsar Timing Array

The timing of radio pulsars provides a tool for studying a wide range of fundamental physical and astrophysical problems. The best results are obtained by regular, frequent timing observations of a large number of sources at various frequencies. We describe a project which aims to improve on all of the above parameters by combining timing data from the pulsar timing programs of 4 European groups to form the so-called EPTA. These data will be used to study, amongst other things, relativistic binaries and gravitational waves

Discovery of short-period binary millisecond pulsars in four globular clusters

We report the discovery, using the Parkes radio telescope, of binary millisecond pulsars in four clusters for which no associated pulsars were previously known. The four pulsars have pulse periods lying between 3 and 6 ms. All are in circular orbits with low-mass companions and have orbital periods of a few days or less. One is in a 1.7 hr orbit with a companion of planetary mass. Another is eclipsed by a wind from its companion for 40% of the binary period despite being in a relatively wide orbit. These discoveries result from the use of improved technologies and prove that many millisecond pulsars remain to be found in globular clusters