We report the detection of a glitch in the millisecond pulsar (MSP) PSR J0900-3144, which is included in the European, MeerKAT, and Parkes pulsar timing array (PTA) experiments. The data set combines observations from the MeerKAT, Nanc,ay, Lovell, and Murriyang telescopes, spanning a total baseline of approximately 14 yr. The glitch occurred on MJD 59942(17), with a measured fractional spin frequency step of Av(g) /v = 1 . 15(13) x 10(-12). This event represents the third glitch detected in an MSP, following those in PSRs B1821-24A and J0613-0200. Although smaller in amplitude than the previous two, the glitch in PSR J0900-3144 is of a comparable order of magnitude. The updated MSP glitch rate is 2 . 5(1) x 10(-3 )glitches per pulsar per year, which suggests it is likely that current PTAs will detect another MSP glitch within 5 yr. Using simulations, we demonstrate that such small glitches can go undetected, especially in short data sets such as those from new PTAs, and can bias the inferred achromatic noise model parameters, potentially leading to the down-weighting of the pulsar in gravitational wave background searches.

The discovery of VHE emission from the Crab pulsar and, more recently, multi-TeV emission from the Vela pulsar have challenged our current understanding of the emission mechanisms of these sources. Studying pulsar emission at TeV energies allows us to understand the engines that power some of the most extreme accelerators in the Galaxy. We present recent highlights from the VERITAS pulsar program using nearly two decades of VERITAS data and novel high energy analysis techniques optimized for emission up to 100 TeV. This work begins to characterize how the emerging population of multi-TeV pulsars can be predicted from existing multi-wavelength observations. In particular, we highlight a search for VHE emission above 1 TeV using over 17 years of Crab pulsar data, which extends the high energy end of the existing VERITAS spectrum. Additionally, we search for both optical and multi-TeV emission from bright Vela-like pulsars, including analysis of over 200 hours of data on PSR J2229+6114, which powers the Boomerang pulsar wind nebula and is putatively associated with the ultra-high-energy source 1LHAASO J2229+5927u. We discuss these results in the context of the broader pulsar population and their impacts on the prospects of new pulsar discoveries with next-generation VHE instruments.

Matter inside neutron stars is compressed to densities several times greater than nuclear saturation density, while maintaining low temperatures and large asymmetries between neutrons and protons. Neutron stars, therefore, provide a unique laboratory for testing physics in environments that cannot be recreated on Earth. To uncover the highly uncertain nature of cold, ultra-dense matter, discovering and monitoring pulsars is essential, and SKA will play a crucial role in this endeavour. In this paper, we will present the current state-of-the-art in dense matter physics and dense matter superfluidity, and discuss recent advances in measuring global neutron star properties (masses, moments of inertia, and maximum rotation frequencies) as well as non-global observables (pulsar glitches and free precession). We will specifically highlight how radio observations of isolated neutron stars and those in binaries---such as those performed with SKA in the near future---inform our understanding of ultra-dense physics and address in detail how SKA's unprecedented sensitivity, large-scale survey and sub-arraying capabilities will enable novel dense matter constraints. We will also address the potential impact of dark matter and modified gravity models on these constraints and emphasise the role of synergies between SKA and other facilities, specifically X-ray telescopes and next-generation gravitational wave observatories.

The shape and polarisation properties of the radio pulse profiles of radio-loud magnetars provide a unique opportunity to investigate their magnetospheric properties. Gaussian Process Regression analysis was used to investigate the variation in the total intensity shape of the radio pulse profiles of the magnetar Swift J1818.0-1607. The observed profile shape was found to evolve through three modes between MJDs 59104 and 59365. The times at which these transitions occurred coincided with changes in the amplitude of modulations in the spin-down rate. The amount of linear and circular polarisation was also found to vary significantly with time. Lomb-Scargle periodogram analysis of the spin-down rate revealed three possibly harmonically related frequencies. This could point to the magnetar experiencing seismic activity. However, no profile features exhibited significant periodicity, suggesting no simple correlations between the profile variability and fluctuations of the spin-down on shorter timescales within the modes. Overall, this implies the mode changes seen are a result of local magnetospheric changes, with other theories, such as precession, less able to explain these observations.

For a selection of 35 pulsars with large spin-up glitches (Delta v/v >= 10(-6)), which are monitored by the Jodrell Bank Observatory, we analyse 157 glitches and their recoveries. All parameters are measured consistently and we choose the best model to describe the post-glitch recovery based on Bayesian evidence. We present updated glitch epochs, sizes, changes of spin down rate, exponentially recovering components (amplitude and corresponding time-scale) when present, as well as pulsars' second frequency derivatives and their glitch-associated changes if detected. We discuss the different observed styles of post-glitch recovery as well as some particularly interesting sources. Several correlations are revealed between glitch parameters and pulsar spin parameters, including a very strong correlation between a pulsar's interglitch |(v) over double dot| and (v) over dot, as well as between the glitch-induced spin-down rate change Delta(v) over dot(p) that does not relax exponentially and (v) over dot. We find that the ratio |Delta(v) over dot(p)/(v) over double dot| can be used as an estimate of glitch recurrence times, especially for those pulsars for which there are indications of a characteristic glitch size and interglitch waiting time. We calculate the interglitch braking index n and find that pulsars with large glitches typically have n greater than 3, suggesting that internal torques dominate the rotational evolution between glitches. The external torque, for example, from electromagnetic dipole radiation, could dominate the observed (v) over double dot for the youngest pulsars (less than or similar to 10(4)yr), which may be expected to display v similar to 3.

We undertake the first targeted search at 1.5 GHz for radio emission from the variable γ-ray pulsar PSR J2021+4026. This radio-quiet pulsar assumes one of two stable γ-ray emission states, between which it transitions on a timescale of years. These transitions, in both γ-ray flux and pulse profile shape, are accompanied by contemporaneous changes to the pulsar's spin-down rate. A number of radio pulsars are known to exhibit similar correlated variability, which in some cases involves an emission state in which the radio emission ceases to be detectable. In this paper, we perform a search for radio emission from PSR J2021+4026, using archival radio observations recorded when the pulsar was in each of its emission/spin-down states. Using improved techniques, we search for periodic radio emission as well as single pulse phenomena such as giant radio pulses and RRAT-like emission. Our search reveals no evidence of radio emission from PSR J2021+4026. We estimate that the flux density for periodic emission from PSR J2021+4026 does not exceed 0.2 mJy at this frequency. We also estimate single-pulse flux limits for RRAT-like bursts and giant radio pulses to be 0.3 and 100 Jy respectively. We discuss the transitioning behaviour of PSR J2021+4026 in the context of pulsar glitches, intermittent pulsars and the increasingly common emission-rotation correlation observed in radio pulsars.

This paper presents high-performance computing efforts with FPGA for the accelerated pulsar/transient search for the square kilometre array (SKA). Case studies are presented from within SKA and pathfinder telescopes highlighting future opportunities. It reviews the scenario that has shifted from offline processing of the radio telescope data to digitizing several hundreds/thousands of antenna outputs over huge bandwidths, forming several hundreds of beams, and processing the data in the SKA real-time pulsar search pipelines. A brief account of the different architectures of the accelerators, primarily, the new generation field programmable gate array-based accelerators, showing their critical roles to achieve high-performance computing and in handling the enormous data volume problems of the SKA is presented here. It also presents power-performance efficiency of this emerging technology and presents potential future scenarios.

ABSTRACT We report on the the long term monitoring campaign of the seemingly youngest magnetar Swift J1818.0–1607 at radio and X-ray wavelengths over a span of one year. We obtained a coherent timing solution for the magnetar over the same time span. The frequency derivative of the magnetar shows systematic variation with the values oscillating about a mean value of −1.37 × 10−11 Hz s−1. The magnitude of the variation in the frequency derivative reduces with time before converging on the mean value. This corresponds to a characteristic age of ∼ 860 years, 2–4 times more than previously estimated. We were able to identify four states in the spin-frequency derivative that were quantified by the amount of modulation about the mean value and the transition between these states seem to be correlated with the change in the radio emission of the magnetar while no correlation is seen in the average radio profile variability on a shorter time-scale (days). The 0.5–12 keV X-ray flux shows a monotonic decrease that can be attributed to thermal emission from a hot spot on the surface of the neutron star that is reducing in size. Such decrease is consistent with what is seen in other magnetars. The potential correlation between the radio emission mode and the behaviour of the spin-down rate hints to a global change in the magnetopshere of the magnetar akin to the correlation seen in a subset of mode-changing radio pulsars and suggests a physical link between the two sub-populations.

Pulsar glitches are rapid spin-up events that occur in the rotation of neutron stars, providing a valuable probe into the physics of the interiors of these objects. Long-term monitoring of a large number of pulsars facilitates the detection of glitches and the robust measurements of their parameters. The Jodrell Bank pulsar timing programme regularly monitors more than 800 radio pulsars and has accrued, in some cases, over 50 years of timing history on individual objects. In this paper we present 106 new glitches in 70 radio pulsars as observed up to the end of 2018. For 70% of these pulsars, the event we report is its only known glitch. For each new glitch we provide measurements of its epoch, amplitude and any detected changes to the spin-down rate of the star. Combining these new glitches with those listed in the Jodrell Bank glitch catalogue we analyse a total sample of 543 glitches in 178 pulsars. We model the distribution of glitch amplitudes and spin-down rate changes using a mixture of two Gaussian components. We corroborate the known dependence of glitch rate and activity on pulsar spin-down rates and characteristic ages, and show that younger pulsars tend to exhibit larger glitches. Pulsars whose spin-down rates between $10^{-14}$ Hz s$^{-1}$ and $10^{-10.5}$ Hz s$^{-1}$ show a mean reversal of 1.8% of their spin-down as a consequence of glitches. Our results are qualitatively consistent with the superfluid vortex unpinning models of pulsar glitches.

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully-coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow the frequency and frequency time-derivative of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets.

We present a targeted search for continuous gravitational waves (GWs) from 236 pulsars using data from the third observing run of LIGO and Virgo (O3) combined with data from the second observing run (O2). Searches were for emission from the $l=m=2$ mass quadrupole mode with a frequency at only twice the pulsar rotation frequency (single harmonic) and the $l=2, m=1,2$ modes with a frequency of both once and twice the rotation frequency (dual harmonic). No evidence of GWs was found so we present 95\% credible upper limits on the strain amplitudes $h_0$ for the single harmonic search along with limits on the pulsars' mass quadrupole moments $Q_{22}$ and ellipticities $\varepsilon$. Of the pulsars studied, 23 have strain amplitudes that are lower than the limits calculated from their electromagnetically measured spin-down rates. These pulsars include the millisecond pulsars J0437\textminus4715 and J0711\textminus6830 which have spin-down ratios of 0.87 and 0.57 respectively. For nine pulsars, their spin-down limits have been surpassed for the first time. For the Crab and Vela pulsars our limits are factors of $\sim 100$ and $\sim 20$ more constraining than their spin-down limits, respectively. For the dual harmonic searches, new limits are placed on the strain amplitudes $C_{21}$ and $C_{22}$. For 23 pulsars we also present limits on the emission amplitude assuming dipole radiation as predicted by Brans-Dicke theory.

ABSTRACT With the ever-increasing sensitivity and timing baselines of modern radio telescopes, a growing number of pulsars are being shown to exhibit transitions in their rotational and radio emission properties. In many of these cases, the two are correlated with pulsars assuming a unique spin-down rate ($\dot{\nu }$) for each of their specific emission states. In this work, we revisit 17 radio pulsars previously shown to exhibit spin-down rate variations. Using a Gaussian process regression (GPR) method to model the timing residuals and the evolution of the profile shape, we confirm the transitions already observed and reveal new transitions in 8 yr of extended monitoring with greater time resolution and enhanced observing bandwidth. We confirm that seven of these sources show emission-correlated $\dot{\nu }$ transitions ($\Delta \dot{\nu }$), and we characterize this correlation for one additional pulsar, PSR B1642−03. We demonstrate that GPR is able to reveal extremely subtle profile variations given sufficient data quality. We also corroborate the dependence of $\Delta \dot{\nu }$ amplitude on $\dot{\nu }$ and pulsar characteristic age. Linking $\Delta \dot{\nu }$ to changes in the global magnetospheric charge density Δρ, we speculate that $\dot{\nu }$ transitions associated with large Δρ values may be exhibiting detectable profile changes with improved data quality, in cases where they have not previously been observed.

This paper presents the Mechanical Ventilator Milano (MVM), a novel intensive therapy mechanical ventilator designed for rapid, large-scale, low-cost production for the COVID-19 pandemic. Free of moving mechanical parts and requiring only a source of compressed oxygen and medical air to operate, the MVM is designed to support the long-term invasive ventilation often required for COVID-19 patients and operates in pressure-regulated ventilation modes, which minimize the risk of furthering lung trauma. The MVM was extensively tested against ISO standards in the laboratory using a breathing simulator, with good agreement between input and measured breathing parameters and performing correctly in response to fault conditions and stability tests. The MVM has obtained Emergency Use Authorization by U.S. Food and Drug Administration (FDA) for use in healthcare settings during the COVID-19 pandemic and Health Canada Medical Device Authorization for Importation or Sale, under Interim Order for Use in Relation to COVID-19. Following these certifications, mass production is ongoing and distribution is under way in several countries. The MVM was designed, tested, prepared for certification, and mass produced in the space of a few months by a unique collaboration of respiratory healthcare professionals and experimental physicists, working with industrial partners, and is an excellent ventilator candidate for this pandemic anywhere in the world.

B. Olaizola, ∗ A. Babu, R. Umashankar, 2 A.B. Garnsworthy, G.C. Ball, V. Bildstein, M. Bowry, † C. Burbadge, R. Cabellero-Folch, I. Dillmann, 4 A. Diaz-Varela, R. Dunlop, A. Estradé, P.E. Garrett, G. Hackman, A.D. MacLean, J. Measures, 6 C.J. Pearson, B. Shaw, D. Southall, ‡ C.E. Svensson, J. Turko, K. Whitmore, and T. Zidar TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada Department of Physics, University of Guelph, Guelph, ON, N1G 2W1, Canada Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8P 5C2, Canada Department of Physics, Central Michigan University, Mount Pleasant, MI 48859, USA Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom Department of Chemistry, Simon Fraser University, Burnaby, British Colombia V5A 1S6, Canada (Dated: September 13, 2021)

Citation for published version (APA): Olaizola, B., Babu, A., Umashankar, R., Garnsworthy, A. B., Ball, G. C., Bildstein, V., Bowry, M., Burbadge, C., Cabellero-Folch, R., Dillmann, I., Diaz-Varela, A., Dunlop, R., Estradé, A., Garrett, P. E., Hackman, G., MacLean, A. D., Measures, J., Pearson, C. J., Shaw, B., ... Zidar, T. (2021). 145 Ba and 146,146 La structure from lifetime measurements. Physical Review C, 104(3), [034307]. https://doi.org/10.1103/PhysRevC.104.034307

AbstractAria is a plant hosting a$${350}\,\hbox {m}$$350mcryogenic isotopic distillation column, the tallest ever built, which is being installed in a mine shaft at Carbosulcis S.p.A., Nuraxi-Figus (SU), Italy. Aria is one of the pillars of the argon dark-matter search experimental program, lead by the Global Argon Dark Matter Collaboration. It was designed to reduce the isotopic abundance of$${^{39}\hbox {Ar}}$$39Arin argon extracted from underground sources, called Underground Argon (UAr), which is used for dark-matter searches. Indeed,$${^{39}\hbox {Ar}}$$39Aris a$$\beta $$β-emitter of cosmogenic origin, whose activity poses background and pile-up concerns in the detectors. In this paper, we discuss the requirements, design, construction, tests, and projected performance of the plant for the isotopic cryogenic distillation of argon. We also present the successful results of the isotopic cryogenic distillation of nitrogen with a prototype plant.

We present updated measurements of the Crab pulsar glitch of 2019 July 23 using a dataset of pulse arrival times spanning ∼5 months. On MJD 58687, the pulsar underwent its seventh largest glitch observed to date, characterised by an instantaneous spin-up of ∼1 μHz. Following the glitch the pulsar’s rotation frequency relaxed exponentially towards pre-glitch values over a timescale of approximately one week, resulting in a permanent frequency increment of ∼0.5 μHz. Due to our semi-continuous monitoring of the Crab pulsar, we were able to partially resolve a fraction of the total spin-up. This delayed spin-up occurred exponentially over a timescale of ∼18 hours. This is the fourth Crab pulsar glitch for which part of the initial rise was resolved in time and this phenomenon has not been observed in any other glitching pulsars, offering a unique opportunity to study the microphysical processes governing interactions between the neutron star interior and the crust.

Future liquid-argon DarkSide-20k and Argo detectors, designed for direct dark matter search, will be sensitive also to core-collapse supernova neutrinos, via coherent elastic neutrino-nucleus scattering. This interaction channel is flavor-insensitive with a high-cross section, enabling for a high-statistics neutrino detection with target masses of similar to 50 t and similar to 360 t for DarkSide-20k and Argo respectively. Thanks to the low-energy threshold of similar to 0.5 keV(nr) achievable by exploiting the ionization channel, DarkSide-20k and Argo have the potential to discover supernova bursts throughout our galaxy and up to the Small Magellanic Cloud, respectively, assuming a 11-M-circle dot progenitor star. We report also on the sensitivity to the neutronization burst, whose electron neutrino flux is suppressed by oscillations when detected via charged current and elastic scattering. Finally, the accuracies in the reconstruction of the average and total neutrino energy in the different phases of the supernova burst, as well as its time profile, are also discussed, taking into account the expected background and the detector response.

We present a search for continuous gravitational waves from five radio pulsars, comprising three recycled pulsars (PSR J0437-4715, PSR J0711-6830, and PSR J0737-3039A) and two young pulsars: the Crab pulsar (J0534+2200) and the Vela pulsar (J0835-4510). We use data from the third observing run of Advanced LIGO and Virgo combined with data from their first and second observing runs. For the first time we are able to match (for PSR J0437-4715) or surpass (for PSR J0711-6830) the indirect limits on gravitational-wave emission from recycled pulsars inferred from their observed spin-downs, and constrain their equatorial ellipticities to be less than $10^{-8}$. For each of the five pulsars, we perform targeted searches that assume a tight coupling between the gravitational-wave and electromagnetic signal phase evolution. We also present constraints on PSR J0711-6830, the Crab pulsar and the Vela pulsar from a search that relaxes this assumption, allowing the gravitational-wave signal to vary from the electromagnetic expectation within a narrow band of frequencies and frequency derivatives.