arXiv subjects

P. V. Padmanabh

Publications and source records attributed to P. V. Padmanabh.

At least 19 recordsLinked to original sources

arXiv2026

Fifteen new millisecond pulsars in 47 Tucanae

47 Tucanae is one of the largest, brightest, and closest globular clusters to Earth. It hosts an exotic stellar population with stellar dynamics that indicate a complex evolution history. The cluster contains a large number of X-ray binaries and millisecond pulsars. However, given its large distance relative to the known pulsar population, previous surveys have found only the very brightest sources. Therefore, surveys with increased sensitivity should find many additional pulsars. Increasing the number of pulsars is crucial to investigate the dynamics of this globular cluster and could also lead to the discovery of unusual types of system. With a significantly increased sensitivity compared to earlier telescopes, MeerKAT is the natural choice to perform new surveys. We carried out two campaigns with different observational cadences to account for the high scintillation along the line of sight to this cluster. Here we report the discovery of fifteen new pulsars in 47 Tucanae with MeerKAT. These discoveries bring the total number of known pulsars in this globular cluster to 42, and the MeerKAT discoveries in this cluster to 17. We discuss some of their characteristics, which include preliminary localisations and estimates of orbits for most systems. Highlights include the discovery of 47 Tuc af, a 'black widow' pulsar with a short orbital period that was identified optically in 2002 as a candidate binary pulsar, and 47 Tuc ai, an eccentric binary pulsar with a massive companion, a unique system in 47 Tuc to date. Apart from the new systems, we also re-detect and localise 47 Tuc P and V, two elusive, seldom-detected systems that had no precise localisation from a phase-connected timing solution. The localisation of 47 Tuc V places it in a position consistent with a continuum source detected earlier in MeerKAT imaging data.

astro-ph.HE↗

arXiv2026

Variability of Sagittarius A* at 3 GHz on minute-scale with MeerKAT

The supermassive black hole Sagittarius A* (Sgr A*) exhibits temporal and spectral variability across the electromagnetic spectrum. However, variability at radio frequencies below ~ 5 GHz for timescales shorter than a day remains largely unexplored. We investigate the variability of Sgr A* at 2.79 GHz on short timescales (1 min), to probe an under-explored regime of its emission process. Through point-source model fitting in the uv-domain, we analyse the flux density variation of Sgr A* over an 8 h observation. We detect flux variation on a few tens of minute timescale with a modulation index of 6.11 %, a mean flux density of ($827 \pm 0.1_{\mathrm{stat}} \pm 33_{\mathrm{sys}}) \, \mathrm{mJy}$, and a mean spectral slope of $0.08\pm0.03$. Furthermore, we measure the slope of the structure function of the observed light curve as $0.81 \pm 0.05$ with a characteristic timescale of about 120 min. Our study at low radio frequencies is a critical step toward constraining the physical mechanisms that drive Sgr A*'s variable emission and its spectral energy distribution. Our study suggests that variability at centimetre and millimetre wavelengths is likely more closely related than previously thought.

astro-ph.GA↗

arXiv2026

PSR J0024$-$7204ai: a massive, eccentric binary system in the globular cluster 47 Tucanae

In this paper we present PSR J0024$-$7204ai, a 13.026-ms binary pulsar recently discovered in the globular cluster 47 Tucanae by the MeerKAT radio telescope. This is the slowest spinning pulsar known in this globular cluster, and has a $\sim1.67$-day orbit with an eccentricity of $e\approx0.18$. Although it was not yet possible to derive an unambiguous phase-connected timing solution, by combining detections obtained from MeerKAT and archival Parkes data we were able to measure the rate of advance of periastron to high significance, $\dotω$ = 0.1601 $\pm 0.0046$ deg yr$^{-1}$. This value implies a total system mass of $2.41 \pm 0.11\, \mathrm{M}_\odot$ (68.3\% C. L.), which, when combined with the binary mass function, gives a maximum pulsar mass of $\sim 1.7 \, \mathrm{M}_\odot$ and a minimum companion mass of $\sim 0.7\, \mathrm{M}_\odot$. Apart from being the slowest pulsar in 47~Tucanae, its orbit is by far the most eccentric and its companion is the most massive among all known binary pulsars in this globular cluster. One possibility is that system is an old MSP - Carbon-Oxygen White Dwarf binary, whose orbit was perturbed by stellar dynamical interactions in the cluster core. Further follow-up observations of this system will be essential for a more detailed characterisation of this system and its evolution.

astro-ph.HE↗

arXiv2025

The TRAPUM Large Magellanic Cloud pulsar survey with MeerKAT II: 12 new discoveries and timing solutions for 7 pulsars

We report the discovery of 12 new radio pulsars in the Large Magellanic Cloud (LMC) as part of the TRAPUM (TRAnsients and PUlsars with MeerKAT) Large Survey Project, using the MeerKAT L-band receivers (856--1712\,MHz). These pulsars, discovered in 18 new pointings with 2\,hour integration times, bring the total number of pulsars identified by this ongoing survey to 19 (yielding a total of 44 LMC radio pulsars now known), representing an 80 per cent increase in the LMC radio pulsar population to date. These include PSR\,J0454$-$6927, the slowest extragalactic radio pulsar discovered to date, with a spin period of 2238\,ms, and PSR\,J0452$-$6921, which exhibits the highest dispersion measure (DM) among extragalactic radio pulsars, at 326\,pc\,cm$^{-3}$. The fastest spin period among the new discoveries is 245\,ms, and the lowest DM is 62\,pc\,cm$^{-3}$. We also present timing results for our first pulsar discoveries with MeerKAT and the Murriyang radio telescope, obtaining phase-connected solutions for seven pulsars in the LMC. These results indicate that the pulsars are isolated, canonical radio pulsars with characteristic ages up to 8.8\,Myr

astro-ph.HE↗

arXiv2025

TRAPUM search for pulsars in supernova remnants and pulsar wind nebulae - II. Survey analysis and population study

We present the second and final set of TRAPUM searches for pulsars at 1284 MHz inside supernova remnants and pulsar wind nebulae with the MeerKAT telescope. No new pulsars were detected for any of the 80 targets, which include some unidentified TeV sources that could be pulsar wind nebulae. The mean upper limit on the flux density of undetected pulsars is 52 $μ$Jy, which includes the average sensitivity loss across the coherent beam tiling pattern. This survey is the largest and most sensitive multi-target campaign of its kind. We explore the selection effects that precluded discoveries by testing the parameters of the survey iteratively against many simulated populations of young pulsars in supernova remnants. For the synthetic pulsars that were undetected, we find evidence that, after beaming effects are accounted for, about 45 per cent of pulsars are too faint, 30 per cent are too smeared by scattering, and a further 25 per cent have a modelled projected location which places them outside their supernova remnant. The simulations are repeated for the S1 subband of the MeerKAT S-band receivers, resulting in a 50-150 per cent increase in the number of discoveries compared to L-band depending on the flux density limit achieved. Therefore, higher frequency searches that can also achieve improved flux density limits are the best hope for future targeted searches. We also report updated properties for the two previous discoveries, including a polarimetry study of PSR J1831$-$0941 finding a rotation measure of 401$\pm$1 rad m$^2$.

astro-ph.HE↗

arXiv2025

NGC 1851A: Revealing an ongoing three-body encounter in a dense globular cluster

PSR J0514$-$4002A is a binary millisecond pulsar located in the globular cluster NGC 1851. The pulsar has a spin period of 4.99 ms, an orbital period of 18.8 days, and is in a very eccentric ($e = 0.89$) orbit around a massive companion. In this work, we present the updated timing analysis of this system, obtained with an additional 1 yr of monthly observations using the Giant Metrewave Radio Telescope and 2.5 yrs of observations using the MeerKAT telescope. This has allowed for a precise measurement of the proper motion of the system, implying a transverse velocity of $30\,\pm\,7\,\mathrm{km}\,\mathrm{s}^{-1}$ relative to the cluster. This is smaller than the cluster's escape velocity and consistent with the pulsar's association to NGC 1851. We have confirmed a large second spin frequency derivative and large associated jerk, which has increased the spin frequency derivative by a factor of 27 since the mid-2000s. The third spin frequency derivative showed that the strength of this jerk has increased by $\sim 65\%$ in the same time period. We take the effect of the changing acceleration into account and this allows for much improved estimates of the orbital period derivative. The large and fast-increasing jerk implies the presence of a third body in the vicinity of the pulsar (no counterpart is detectable within distance limit in HST images). Based on our measured parameters, we constrain the mass, distance and orbital parameters for this third body. The induced tidal contributions to the post-Keplerian parameters are small, and the precise measurement of these parameters allowed us to obtain precise mass measurements for the system: $M_\mathrm{tot} = 2.4734(3)$ M$_{\odot}$, $M_\mathrm{p} = 1.39(3)$ M$_{\odot}$, $M_\mathrm{c} = 1.08(3)$ M$_{\odot}$. This indicates that the pulsar's companion is a massive white dwarf and resolves the earlier ambiguity regarding its nature.

astro-ph.HE↗

arXiv2024

Radio and gamma-ray timing of TRAPUM L-band Fermi pulsar survey discoveries

This paper presents the results of a joint radio and gamma-ray timing campaign on the nine millisecond pulsars (MSPs) discovered as part of the L-band targeted survey of Fermi-LAT sources performed in the context of the Transients and Pulsars with MeerKAT (TRAPUM) Large Survey Project. Out of these pulsars, eight are members of binary systems; of these eight, two exhibit extended eclipses of the radio emission. Using an initial radio timing solution, pulsations were found in the gamma rays for six of the targets. For these sources, a joint timing analysis of radio times of arrival and gamma-ray photons was performed, using a newly developed code that optimises the parameters through a Markov chain Monte Carlo (MCMC) technique. This approach has allowed us to precisely measure both the short- and long-term timing parameters. This study includes a proper motion measurement for four pulsars, which a gamma ray-only analysis would not have been sensitive to, despite the 15-year span of Fermi data.

astro-ph.HE↗

arXiv2024

TRAPUM pulsar and transient search in the Sextans A and B galaxies and discovery of background FRB 20210924D

The Small and Large Magellanic Clouds are the only galaxies outside our own in which radio pulsars have been discovered to date. The sensitivity of the MeerKAT radio interferometer offers an opportunity to search for a population of more distant extragalactic pulsars. The TRAPUM (TRansients And PUlsars with MeerKAT) collaboration has performed a radio-domain search for pulsars and transients in the dwarf star-forming galaxies Sextans A and B, situated at the edge of the local group 1.4 Mpc away. We conducted three 2-hour multi-beam observations at L-band (856-1712 MHz) with the full array of MeerKAT. No pulsars were found down to a radio pseudo-luminosity upper limit of 7.9$\pm$0.4 Jy kpc$^{2}$ at 1400 MHz, which is 28 times more sensitive than the previous limit from the Murriyang telescope. This luminosity is 30 per cent greater than that of the brightest known radio pulsar and sets a cut-off on the luminosity distributions of the entire Sextans A and B galaxies for unobscured radio pulsars beamed in our direction. A Fast Radio Burst was detected in one of the Sextans A observations at a Dispersion Measure (DM) of 737 pc cm$^{-3}$. We believe this is a background event not associated with the dwarf galaxy due to its large DM and its S/N being strongest in the wide-field incoherent beam of MeerKAT.

astro-ph.HE↗

arXiv2024

Searching for Pulsars, Magnetars, and Fast Radio Bursts in the Sculptor Galaxy using MeerKAT

The Sculptor Galaxy (NGC 253), located in the Southern Hemisphere, far off the Galactic Plane, has a relatively high star-formation rate of about 7 M$_{\odot}$ yr$^{-1}$ and hosts a young and bright stellar population, including several super star clusters and supernova remnants. It is also the first galaxy, apart from the Milky Way Galaxy to be associated with two giant magnetar flares. As such, it is a potential host of pulsars and/or fast radio bursts in the nearby Universe. The instantaneous sensitivity and multibeam sky coverage offered by MeerKAT therefore make it a favourable target. We searched for pulsars, radio-emitting magnetars, and fast radio bursts in NGC 253 as part of the TRAPUM large survey project with MeerKAT. We did not find any pulsars during a four-hour observation, and derive a flux density limit of 4.4 $μ$Jy at 1400 MHz, limiting the pseudo-luminosity of the brightest putative pulsar in this galaxy to 54 Jy kpc$^2$. Assuming universality of pulsar populations between galaxies, we estimate that detecting a pulsar as bright as this limit requires NGC 253 to contain a pulsar population of $\gtrsim$20 000. We also did not detect any single pulses and our single pulse search flux density limit is 62 mJy at 1284 MHz. Our search is sensitive enough to have detected any fast radio bursts and radio emission similar to the brighter pulses seen from the magnetar SGR J1935+2154 if they had occurred during our observation.

astro-ph.HE↗

arXiv2024

The TRAPUM Large Magellanic Cloud pulsar survey with MeerKAT I: Survey setup and first seven pulsar discoveries

The Large Magellanic Cloud (LMC) presents a unique environment for pulsar population studies due to its distinct star formation characteristics and proximity to the Milky Way. As part of the TRAPUM (TRAnsients and PUlsars with MeerKAT) Large Survey Project, we are using the core array of the MeerKAT radio telescope (MeerKAT) to conduct a targeted search of the LMC for radio pulsars at L-band frequencies, 856-1712$\,$MHz. The excellent sensitivity of MeerKAT, coupled with a 2-hour integration time, makes the survey 3 times more sensitive than previous LMC radio pulsar surveys. We report the results from the initial four survey pointings which has resulted in the discovery of seven new radio pulsars, increasing the LMC radio pulsar population by 30 per cent. The pulse periods of these new pulsars range from 278 to 1690$\,$ms, and the highest dispersion measure is 254.20$\,$pc$\,$cm$^{-3}$. We searched for, but did not find any significant pulsed radio emission in a beam centred on the SN$\,$1987A remnant, establishing an upper limit of 6.3$\,μ$Jy on its minimum flux density at 1400$\,$MHz.

astro-ph.HE↗

arXiv2024

The TRAPUM Small Magellanic Cloud pulsar survey with MeerKAT -- II. Nine new radio timing solutions and glitches from young pulsars

We report new radio timing solutions from a three-year observing campaign conducted with the MeerKAT and Murriyang telescopes for nine Small Magellanic Cloud pulsars, increasing the number of characterised rotation-powered extragalactic pulsars by 40 per cent. We can infer from our determined parameters that the pulsars are seemingly all isolated, that six are ordinary pulsars, and that three of the recent MeerKAT discoveries have a young characteristic age of under 100 kyr and have undergone a spin-up glitch. Two of the sources, PSRs J0040$-$7337 and J0048$-$7317, are energetic young pulsars with spin-down luminosities of the order of 10$^{36}$ erg s$^{-1}$. They both experienced a large glitch, with a change in frequency of about 30 $μ$Hz, and a frequency derivative change of order $-10^{-14}$ Hz s$^{-1}$. These glitches, the inferred glitch rate, and the properties of these pulsars (including potentially high inter-glitch braking indices) suggest these neutron stars might be Vela-like repeating glitchers and should be closely monitored in the future. The position and energetics of PSR J0048$-$7317 confirm it is powering a new Pulsar Wind Nebula (PWN) detected as a radio continuum source; and similarly the association of PSR J0040$-$7337 with the PWN of Supernova Remnant (SNR) DEM S5 (for which we present a new Chandra image) is strengthened. Finally, PSR J0040$-$7335 is also contained within the same SNR but is a chance superposition. It has also been seen to glitch with a change of frequency of $10^{-2}$ $μ$Hz. This work more than doubles the characterised population of SMC radio pulsars.

astro-ph.HE↗

arXiv2024

Discovery and timing of ten new millisecond pulsars in the globular cluster Terzan 5

We report the discovery of ten new pulsars in the globular cluster Terzan 5 as part of the Transients and Pulsars with MeerKAT (TRAPUM) Large Survey Project. We observed Terzan 5 at L-band (856--1712 MHz) with the MeerKAT radio telescope for four hours on two epochs, and performed acceleration searches of 45 out of 288 tied-array beams covering the core of the cluster. We obtained phase-connected timing solutions for nine discoveries, covering nearly two decades of archival observations from the Green Bank Telescope for all but one. Highlights include PSR J1748$-$2446ao which is an eccentric ($e = 0.32$) wide-orbit (orbital period $P_{\rm b} = 57.55$ d) system. We were able to measure the rate of advance of periastron ($\dotω$) for this system allowing us to determine a total mass of $3.17 \pm \, 0.02\, \rm M_{\odot}$. With a minimum companion mass ($M_{\rm c}$) of $\sim 0.8\, \rm M_{\odot}$, PSR J1748$-$2446ao is a candidate double neutron star (DNS) system. If confirmed to be a DNS, it would be the fastest spinning pulsar ($P = 2.27$ ms) and the longest orbital period measured for any known DNS system. PSR J1748$-$2446ap has the second highest eccentricity for any recycled pulsar ($e \sim 0.905$) and for this system we can measure the total mass ($1.997 \pm 0.006\, \rm M_{\odot}$) and also estimate the individual pulsar and companion masses. PSR J1748$-$2446ar is an eclipsing redback (minimum $M_{\rm c} \sim 0.34\, \rm M_{\odot}$) system whose properties confirm it to be the counterpart to a previously published source identified in radio and X-ray imaging. With these discoveries, the total number of confirmed pulsars in Terzan 5 is 49, the highest for any globular cluster so far. These discoveries further enhance the rich set of pulsars known in Terzan 5 and provide scope for a deeper understanding of binary stellar evolution, cluster dynamics and ensemble population studies.

astro-ph.HE↗

arXiv2024

TRAPUM search for pulsars in supernova remnants and pulsar wind nebulae -- I. Survey description and initial discoveries

We present the description and initial results of the TRAPUM (TRAnsients And PUlsars with MeerKAT) search for pulsars associated with supernova remnants (SNRs), pulsar wind nebulae and unidentified TeV emission. The list of sources to be targeted includes a large number of well-known candidate pulsar locations but also new candidate SNRs identified using a range of criteria. Using the 64-dish MeerKAT radio telescope, we use an interferometric beamforming technique to tile the potential pulsar locations with coherent beams which we search for radio pulsations, above a signal-to-noise of 9, down to an average flux density upper limit of 30 $μ$Jy. This limit is target-dependent due to the contribution of the sky and nebula to the system temperature. Coherent beams are arranged to overlap at their 50 per cent power radius, so the sensitivity to pulsars is not degraded by more than this amount, though realistically averages around 65 per cent if every location in the beam is considered. We report the discovery of two new pulsars; PSR J1831$-$0941 is an adolescent pulsar likely to be the plerionic engine of the candidate PWN G20.0+0.0, and PSR J1818$-$1502 appears to be an old and faint pulsar that we serendipitously discovered near the centre of a SNR already hosting a compact central object. The survey holds importance for better understanding of neutron star birth rates and the energetics of young pulsars.

astro-ph.HE↗

arXiv2024

The TRAPUM Small Magellanic Cloud pulsar survey with MeerKAT: I. Discovery of seven new pulsars and two Pulsar Wind Nebula associations

The sensitivity of the MeerKAT radio interferometer is an opportunity to probe deeper into the population of rare and faint extragalactic pulsars. The TRAPUM (TRAnsients and PUlsars with MeerKAT) collaboration has conducted a radio-domain search for accelerated pulsars and transients in the Small Magellanic Cloud (SMC). This partially targeted survey, performed at L-band (856-1712 MHz) with the core array of the MeerKAT telescope in 2-h integrations, is twice as sensitive as the latest SMC radio pulsar survey. We report the discovery of seven new SMC pulsars, doubling this galaxy's radio pulsar population and increasing the total extragalactic population by nearly a quarter. We also carried out a search for accelerated millisecond pulsars in the SMC Globular Cluster NGC 121 using the full array of MeerKAT. This improved the previous upper limit on pulsed radio emission from this cluster by a factor of six. Our discoveries reveal the first radio pulsar-PWN systems in the SMC, with only one such system previously known outside our galaxy (the "Crab pulsar twin" in the Large Magellanic Cloud, PSR J0540$-$6919). We associate the 59 ms pulsar discovery PSR J0040$-$7337, now the fastest spinning radio pulsar in the SMC, with the bow-shock Pulsar Wind Nebula (PWN) of Supernova Remnant DEM S5. We also present a new young pulsar with a 79 ms period, PSR J0048$-$7317, in a PWN recently discovered in a MeerKAT radio continuum image. Using the multi-beam capability of MeerKAT, we localised our pulsar discoveries, and two previous Murriyang discoveries, to a positional uncertainty of a few arcseconds.

astro-ph.HE↗

arXiv2024

Discoveries and Timing of Pulsars in M62

Using MeerKAT, we have discovered three new millisecond pulsars (MSPs) in the bulge globular cluster M62: M62H, M62I, and M62J. All three are in binary systems, which means all ten known pulsars in the cluster are in binaries. M62H has a planetary-mass companion with a median mass $M_{\rm c,med} \sim 3$ M$_{\rm J}$ and a mean density of $ρ\sim 11$ g cm$^{-3}$. M62I has an orbital period of 0.51 days and a $M_{\rm c,med} \sim 0.15$ M$_{\odot}$. Neither of these low-mass systems exhibit eclipses. M62J has only been detected in the two UHF band (816 MHz) observations with a flux density $S_{816} = 0.08$ mJy. The non-detection in the L-band (1284 MHz) indicates it has a relatively steep spectrum ($β< -3.1$). We also present 23-yr-long timing solutions obtained using data from the Parkes "Murriyang", Effelsberg and MeerKAT telescopes for the six previously known pulsars. For all these pulsars, we measured the second spin-period derivatives and the rate of change of orbital period caused by the gravitational field of the cluster, and their proper motions. From these measurements, we conclude that the pulsars' maximum accelerations are consistent with the maximum cluster acceleration assuming a core-collapsed mass distribution. Studies of the eclipses of the redback M62B and the black widow M62E at four and two different frequency bands, respectively, reveal a frequency dependence with longer and asymmetric eclipses at lower frequencies. The presence of only binary MSPs in this cluster challenges models which suggest that the MSP population of core-collapsed clusters should be dominated by isolated MSPs.

astro-ph.HE↗

arXiv2024

A targeted radio pulsar survey of redback candidates with MeerKAT

Redbacks are millisecond pulsar binaries with low mass, irradiated companions. These systems have a rich phenomenology that can be used to probe binary evolution models, pulsar wind physics, and the neutron star mass distribution. A number of high-confidence redback candidates have been identified through searches for variable optical and X-ray sources within the localisation regions of unidentified but pulsar-like Fermi-LAT gamma-ray sources. However, these candidates remain unconfirmed until pulsations are detected. As part of the TRAPUM project, we searched for radio pulsations from six of these redback candidates with MeerKAT. We discovered three new radio millisecond pulsars, PSRs J0838$-$2527, J0955$-$3947 and J2333$-$5526, confirming their redback nature. PSR J0838$-$2827 remained undetected for two years after our discovery despite repeated observations, likely due to evaporated material absorbing the radio emission for long periods of time. While, to our knowledge, this system has not undergone a transition to an accreting state, the disappearance, likely caused by extreme eclipses, illustrates the transient nature of spider pulsars and the heavy selection bias in uncovering their radio population. Radio timing enabled the detection of gamma-ray pulsations from all three pulsars, from which we obtained 15-year timing solutions. All of these sources exhibit complex orbital period variations consistent with gravitational quadrupole moment variations in the companion stars. These timing solutions also constrain the binary mass ratios, allowing us to narrow down the pulsar masses. We find that PSR J2333$-$5526 may have a neutron star mass in excess of 2 M$_{\odot}$.

astro-ph.HE↗

arXiv2024

Mass estimates from optical modelling of the new TRAPUM redback PSR J1910-5320

Spider pulsars continue to provide promising candidates for neutron star mass measurements. Here we present the discovery of PSR~J1910$-$5320, a new millisecond pulsar discovered in a MeerKAT observation of an unidentified \textit{Fermi}-LAT gamma-ray source. This pulsar is coincident with a recently identified candidate redback binary, independently discovered through its periodic optical flux and radial velocity. New multi-color optical light curves obtained with ULTRACAM/NTT in combination with MeerKAT timing and updated SOAR/Goodman spectroscopic radial velocity measurements allow a mass constraint for PSR~J1910$-$5320. \texttt{Icarus} optical light curve modelling, with streamlined radial velocity fitting, constrains the orbital inclination and companion velocity, unlocking the binary mass function given the precise radio ephemeris. Our modelling aims to unite the photometric and spectroscopic measurements available by fitting each simultaneously to the same underlying physical model, ensuring self-consistency. This targets centre-of-light radial velocity corrections necessitated by the irradiation endemic to spider systems. Depending on the gravity darkening prescription used, we find a moderate neutron star mass of either $1.6\pm0.2$ or $1.4\pm0.2$ $M_\odot$. The companion mass of either $0.45\pm0.04$ or $0.43^{+0.04}_{-0.03}$ $M_\odot$ also further confirms PSR~J1910$-$5320 as an irradiated redback spider pulsar.radiated redback spider pulsar.

astro-ph.HE↗

arXiv2023

A MeerKAT view of the pulsars in the globular cluster NGC 6522

We present the results of observations aimed at discovering and studying pulsars in the core-collapsed globular cluster (GC) NGC 6522 performed by the MeerTIME and TRAPUM Large Survey Project with the MeerKAT telescope. We have discovered two new isolated pulsars bringing the total number of known pulsars in the cluster to six. PSR J1803$-$3002E is a mildly recycled pulsar with spin period of 17.9 ms while pulsar PSR J1803$-$3002F is a slow pulsar with spin period of 148.1 ms. The presence of isolated and slow pulsars is expected in NGC 6522 and confirms the predictions of previous theories for clusters at this stage in evolution. We further present a tentative timing solution for the millisecond pulsar (MSP) PSR J1803$-$3002C combining older observations taken with the Parkes 64m radio telescope, Murriyang. This solution implies a relatively small characteristic age of the pulsar in contrast with the old age of the GC. The presence of a slow pulsar and an apparently young MSP, both rare in GCs, suggests that their formation might be linked to the evolutionary stage of the cluster.

astro-ph.HE↗