Eight new millisecond pulsars from the first MeerKAT globular cluster census
A. Ridolfi, T. Gautam, P. C. C. Freire, S. M. Ransom, S. J. Buchner, A. Possenti, V. Venkatraman Krishnan, M. Bailes, M. Kramer, B. W. Stappers, F. Abbate, E. D… 展开作者
A. Ridolfi, T. Gautam, P. C. C. Freire, S. M. Ransom, S. J. Buchner, A. Possenti, V. Venkatraman Krishnan, M. Bailes, M. Kramer, B. W. Stappers, F. Abbate, E. D. Barr, M. Burgay, F. Camilo, A. Corongiu, A. Jameson, P. V. Padmanabh, L. Vleeschower, D. J. Champion, M. Geyer, A. Karastergiou, R. Karuppusamy, A. Parthasarathy, D. J. Reardon, M. Serylak, R. M. Shannon, R. Spiewak
备注：
20 pages, 10 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society
We have used the central 44 antennas of the new 64-dish MeerKAT radio telescope array to conduct a deep search for new pulsars in the core of nine globular clusters. This has led to the discovery of eight new millisecond pulsars in six different clusters. Two new binaries, 47 Tuc ac and 47 Tuc ad, are eclipsing "spiders", featuring compact orbits ($\lesssim 0.32$ days), very low-mass companions and regular occultations of their pulsed emission. The other three new binary pulsars (NGC 6624G, M62G, and Ter 5 an) are in wider ($> 0.7$ days) orbits, with companions that are likely to be white dwarfs or neutron stars. NGC 6624G has a large eccentricity of $e\simeq 0.38$, which enabled us to detect the rate of advance of periastron. This suggests that the system is massive, with a total mass of $M{\rm tot} = 2.65 \pm 0.07$ M$_{\odot}$. Likewise, for Ter 5 an, with $e \simeq 0.0066$, we obtain $M{\rm tot}= 2.97 \pm 0.52$ M$_{\odot}$. The other three new discoveries (NGC 6522D, NGC 6624H and NGC 6752F) are faint isolated pulsars. Finally, we have used the whole MeerKAT array and synthesized 288 beams, covering an area of $\sim2$ arcmin in radius around the center of NGC 6624. This has allowed us to localize many of the pulsars in the cluster, demonstrating the beamforming capabilities of the TRAPUM software backend and paving the way for the upcoming MeerKAT globular cluster pulsar survey.
Using the state-of-the-art SKA precursor, the MeerKAT radio telescope, we explore the limits to precision pulsar timing of millisecond pulsars achievable due to pulse stochasticity (jitter). We report new jitter measurements in 15 of the 29 pulsars in our sample and find that the levels of jitter can vary dramatically between them. For some, like the 2.2~ms pulsar PSR J2241--5236, we measure an implied jitter of just $\sim$ 4~ns/hr, while others like the 3.9~ms PSR J0636--3044 are limited to $\sim$ 100 ns/hr. While it is well known that jitter plays a central role to limiting the precision mea…
Discovery of Millisecond Pulsars toward the Galactic Bulge in an Image-based Survey with MeerKAT
Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（爱因斯坦研究所））；Leibniz Universität Hannover（汉诺威莱布尼茨大学）；Center for Gravitation, Cosmology, and Astrophysics, Department of Physics and Astronomy, University of Wisconsin-Milwaukee（威斯康星大学密尔沃基分校物理与天文学系引力、宇宙学与天体物理中心）；Department of Physics and Astronomy, University of North Carolina at Chapel Hill（北卡罗来纳大学教堂山分校物理与天文学系）；National Radio Astronomy Observatory（国家射电天文台）；Department of Engineering and Physics, Sweet Briar College（斯威特布莱尔学院工程与物理系）；U.S. Naval Research Laboratory（美国海军研究实验室）
We report the discovery of two Black Widow millisecond pulsars in the globular cluster M28 with the MeerKAT telescope. PSR J1824$-$2452M (M28M) is a 4.78-ms pulsar in a $5.82\,$hour orbit and PSR J1824$-$2452N (M28N) is a 3.35-ms pulsar in a $4.76\,$hour orbit. Both pulsars have dispersion measures near $119.30\,$pc$\,$cm$^{-3}$ and have low mass companion stars ($\sim$$0.01-0.03\,$M$_\odot$), which do not cause strong radio eclipses or orbital variations. Including these systems, there are now five known black widow pulsars in M28. The pulsar searches were conducted as a part of an initial ph…
Globular clusters are known to host an unusually large population of millisecond pulsar when compared to the Galactic disk. This is thanks to the high rate of dynamical encounters occurring in the clusters that can create the conditions to efficiently recycle neutron stars into millisecond pulsars. The result is a rich population of pulsars with properties and companions difficult or impossible to replicate in the Galactic disk. For these reasons, globular clusters have been and still are a prime target of searches for new and exciting pulsars. Because of their large distances, the limiting fa…
MeerTime is a five-year Large Survey Project to time pulsars with MeerKAT, the 64-dish South African precursor to the Square Kilometre Array. The science goals for the programme include timing millisecond pulsars (MSPs) to high precision (< 1 $μ$s) to study the Galactic MSP population and to contribute to global efforts to detect nanohertz gravitational waves with the International Pulsar Timing Array (IPTA). In order to plan for the remainder of the programme and to use the allocated time most efficiently, we have conducted an initial census with the MeerKAT "L-band" receiver of 189 MSPs visi…
Precision timing of millisecond pulsars in binary systems enables observers to detect the relativistic Shapiro delay induced by space time curvature. When favourably aligned, this enables constraints to be placed on the component masses and system orientation. Here we present the results of timing campaigns on seven binary millisecond pulsars observed with the 64-antenna MeerKAT radio telescope that show evidence of Shapiro delay: PSRs~J0101$-$6422, J1101$-$6424, J1125$-$6014, J1514$-$4946, J1614$-$2230, J1732$-$5049, and J1909$-$3744. Evidence for Shapiro delay was found in all of the systems…
Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）；Fakultät für Physik, Universität Bielefeld（比勒费尔德大学物理学院）；Rheinische Friedrich-Wilhelms-Universität Bonn（波恩大学）；South African Radio Astronomy Observatory（南非射电天文观测站）；INAF – Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）
We present a comprehensive census of X-ray millisecond pulsars (MSPs) in 29 Galactic globular clusters (GCs), including 68 MSPs with confirmed X-ray luminosities and 107 MSPs with X-ray upper limits. We compile previous X-ray studies of GC MSPs, and add new analyses of six MSPs (PSRs J1326$-$4728A, J1326$-$4728B, J1518$+$0204C, J1717$+$4308A, J1737$-$0314A, and J1807$-$2459A) discovered in five GCs. Their X-ray spectra are well described by a single blackbody model, a single power-law model, or a combination of them, with X-ray luminosities ranging from 1.9$\times$10$^{30}$ erg s$^{-1}$ to 8.3…
We have conducted a systematic survey for the X-ray properties of millisecond pulsars (MSPs). Currently, there are 47 MSPs with confirmed X-ray detections. We have also placed the upper limits for the X-ray emission from the other 36 MSPs by using the archival data. We have normalized their X-ray luminosities $L_{x}$ and their effective photon indices $Γ$ into a homogeneous data set, which enable us to carry out a detailed statistical analysis. Based on our censored sample, we report a relation of $L_{x}\simeq10^{31.05}\left(\dot{E}/10^{35}\right)^{1.31}$ erg/s (2-10 keV) for the MSPs. The inf…
We report the discovery of 13 new pulsars in the globular cluster NGC 1851 by the TRAPUM Large Survey Project using the MeerKAT radio telescope. The discoveries consist of six isolated millisecond pulsars (MSPs) and seven binary pulsars, of which six are MSPs and one is mildly recycled. For all the pulsars, we present the basic kinematic, astrometric, and orbital parameters, where applicable, as well as their polarimetric properties, when these are measurable. Two of the binary MSPs (PSR J0514-4002D and PSR J0514-4002E) are in wide and extremely eccentric (e > 0.7) orbits with a heavy white dw…
Radio and Gamma-Ray Timing of a Newly Discovered Millisecond Pulsar
University of Wisconsin-Milwaukee（密尔沃基威斯康星大学）；Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（爱因斯坦研究所））；Leibniz Universität Hannover（汉诺威莱布尼茨大学）；University of North Carolina at Chapel Hill（北卡罗来纳大学教堂山分校）
We present baseband radio observations of the millisecond pulsar J1909$-$3744, the most precisely timed pulsar, using the MeerKAT telescope as part of the MeerTime pulsar timing array campaign. During a particularly bright scintillation event the pulsar showed strong evidence of pulse mode changing, among the first millisecond pulsars and the shortest duty cycle millisecond pulsar to do so. Two modes appear to be present, with the weak (lower signal-to-noise ratio) mode arriving $9.26$ $\pm 3.94$ $μ$s earlier than the strong counterpart. Further, we present a new value of the jitter noise for …
Discovery of two new millisecond pulsars towards the Galactic bulge
NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；University of Maryland（马里兰大学）；LAPTh, CNRS, USMB（拉普特实验室，法国国家科学研究中心，萨瓦大学）；Université Grenoble Alpes, CNRS, IPAG（格勒诺布尔阿尔卑斯大学，法国国家科学研究中心，天体物理学与行星学研究所）；Australia Telescope National Facility, CSIRO, Space and Astronomy（澳大利亚望远镜国家设施，CSIRO空间与天文部门）；Western Sydney University（西悉尼大学）；George Mason University（乔治梅森大学）；Naval Research Laboratory（海军研究实验室）；Department of Engineering and Physics, Sweet Briar College（斯威特布莱尔学院工程与物理系）；National Radio Astronomy Observatory（美国国家射电天文台）；Fakultät für Physik, Universität Bielefeld（比勒费尔德大学物理学院）；INAF – Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）；Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（阿尔伯特·爱因斯坦研究所））；Leibniz Universität Hannover（汉诺威莱布尼茨大学）
Radio mini-haloes are poorly-understood, moderately-extended diffuse radio sources that trace the presence of magnetic fields and relativistic electrons on scales of hundreds of kiloparsecs, predominantly in relaxed clusters. With relatively few confirmed detections to-date, many questions remain unanswered. This paper presents new radio observations of the galaxy cluster MS1455.0$+$2232 performed with MeerKAT (covering the frequency range 872$-$1712 MHz) and LOFAR (covering 120$-$168 MHz), the first results from a homogeneously selected mini-halo census. We find that this mini-halo extends fo…
Magneto-Active Environments in Pulsar Binaries with the MeerKAT Telescope: I. Pulsar sample and their basic properties
University of Cape Town（开普敦大学）；Tsinghua University（清华大学）；SKA Observatory（平方公里阵列射电望远镜天文台）；INAF-Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；University of Botswana（博茨瓦纳大学）；McGill University（麦吉尔大学）
We report 4 new pulsars discovered in the core-collapsed globular cluster (GC) NGC 6624 by the TRAPUM Large Survey Project with the MeerKAT telescope. All of the new pulsars found are isolated. PSR J1823$-$3021I and PSR J1823$-$3021K are millisecond pulsars with period of respectively 4.319 ms and 2.768 ms. PSR J1823$-$3021J is mildly recycled with a period of 20.899 ms, and PSR J1823$-$3022 is a long period pulsar with a period of 2.497 s. The pulsars J1823$-$3021I, J1823$-$3021J, and J1823$-$3021K have position and dispersion measure (DM) compatible with being members of the GC and are there…
We describe system verification tests and early science results from the pulsar processor (PTUSE) developed for the newly-commissioned 64-dish SARAO MeerKAT radio telescope in South Africa. MeerKAT is a high-gain (~2.8 K/Jy) low-system temperature (~18 K at 20cm) radio array that currently operates from 580-1670 MHz and can produce tied-array beams suitable for pulsar observations. This paper presents results from the MeerTime Large Survey Project and commissioning tests with PTUSE. Highlights include observations of the double pulsar J0737-3039A, pulse profiles from 34 millisecond pulsars fro…
We report the discovery of a new 5.78 ms-period millisecond pulsar (MSP), PSR J1740-5340B (NGC 6397B), in an eclipsing binary system discovered with the Parkes radio telescope (now also known as Murriyang), Australia, and confirmed with the MeerKAT radio telescope in South Africa. The measured orbital period, 1.97 days, is the longest among all eclipsing binaries in globular clusters (GCs) and consistent with that of the coincident X-ray source U18, previously suggested to be a 'hidden MSP'. Our XMM-Newton observations during NGC 6397B's radio quiescent epochs detected no X-ray flares. NGC 639…
We report the detection of 48 millisecond pulsars (MSPs) out of 75 observed thus far using the LOFAR in the frequency range 110-188 MHz. We have also detected three MSPs out of nine observed in the frequency range 38-77 MHz. This is the largest sample of MSPs ever observed at these low frequencies, and half of the detected MSPs were observed for the first time at frequencies below 200 MHz. We present the average pulse profiles of the detected MSPs, their effective pulse widths, and flux densities and compare these with higher observing frequencies. The flux-calibrated, multifrequency LOFAR pul…
We present a deep Chandra X-ray Observatory study of the peculiar binary radio millisecond pulsar PSR J1740--5340 and candidate millisecond pulsars (MSPs) in the globular cluster NGC 6397. The X-rays from PSR J1740--5340 appear to be non-thermal and exhibit variability at the binary period. These properties suggest the presence of a relativistic intrabinary shock formed due to interaction of a relativistic rotation-powered pulsar wind and outflow from the unusual "red-straggler/sub-subgiant" companion. We find the X-ray source U18 to show similar X-ray and optical properties to those of PSR J1…
We report the discovery of a variable optical and X-ray source within the error ellipse of the previously unassociated Fermi Large Area Telescope $γ$-ray source 4FGL J0407.7--5702. A 22 ksec observation from XMM-Newton/EPIC shows an X-ray light curve with rapid variability and flaring. The X-ray spectrum is well-fit by a hard power law with $Γ= 1.7$. Optical photometry taken over several epochs is dominated by aperiodic variations of moderate amplitude. Optical spectroscopy with SOAR and Gemini reveals a blue continuum with broad and double-peaked H and He emission, as expected for an accretio…
Multiwavelength Evidence for Two New Candidate Transitional Millisecond Pulsars in the Sub-luminous Disk State: 4FGL J0639.1--8009 and 4FGL J1824.2+1231
The first MeerKAT S-band globular cluster pulsar survey
University of Cagliari（卡利亚里大学）；INAF – Astronomical Observatory of Cagliari (OAC)（意大利国家天体物理研究所 - 卡利亚里天文台（OAC））；Fakultät für Physik, Universität Bielefeld（比勒费尔德大学物理学院）；Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）；National Radio Astronomy Observatory（美国国家射电天文台）；Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester（曼彻斯特大学物理与天文学系乔德雷尔银行天体物理学中心）
首次 MeerKAT S 波段巡天搜索 14 个球状星团，重新探测 39 颗已知脉冲星并新发现 4 颗毫秒脉冲星，验证了高频搜索在强色散环境中的有效性。
We present the discovery of a new optical/X-ray source likely associated with the Fermi $γ$-ray source 4FGL J1408.6-2917. Its high-amplitude periodic optical variability, large spectroscopic radial velocity semi-amplitude, evidence for optical emission lines and flaring, and X-ray properties together imply the source is probably a new black widow millisecond pulsar binary. We compile the properties of the 41 confirmed and suspected field black widows, finding a median secondary mass of $0.027\pm0.003\,M_{\odot}$. Considered jointly with the more massive redback millisecond pulsar binaries, we …
The Green Bank North Celestial Cap (GBNCC) pulsar survey will cover the entire northern sky ($δ> -40^\circ$) at 350 MHz, and is one of the most uniform and sensitive all-sky pulsar surveys to date. We have created a pipeline to re-analyze GBNCC survey data to take a 350MHz census of all pulsars detected by the survey, regardless of their discovery survey. Of the 1413 pulsars in the survey region, we were able to recover 661. For these we present measured signal-to-noise ratios (S/N), flux densities, pulse widths, profiles, and where appropriate, refined dispersion measurements (647 out of 661)…
We present the results of simultaneous observations of the transitional millisecond pulsar (tMSP) candidate CXOU J110926.4-650224 with the XMM-Newton satellite and the MeerKAT telescope. The source was found at an average X-ray luminosity of $L_{\rm X}\simeq7\times10^{33}$ erg s$^{-1}$ over the 0.3-10 keV band (assuming a distance of 4 kpc) and displayed a peculiar variability pattern in the X-ray emission, switching between high, low and flaring modes on timescales of tens of seconds. A radio counterpart was detected at a significance of 7.9$σ$ with an average flux density of $\simeq$33$μ$Jy …
The MeerKAT telescope represents an outstanding opportunity for radio pulsar timing science with its unique combination of a large collecting area and aperture efficiency (effective area $\sim$7500 m$^2$), system temperature ($T<20$K), high slew speeds (1-2 deg/s), large bandwidths (770 MHz at 20cm wavelengths), southern hemisphere location (latitude $\sim -30^\circ$) and ability to form up to four sub-arrays. The MeerTime project is a five-year program on the MeerKAT array by an international consortium that will regularly time over 1000 radio pulsars to perform tests of relativistic gravity,…
A Multifrequency Census of 100 Pulsars below 100 MHz with LWA: A Systematic Study of Flux Density, Spectra, Timing, Dispersion, Polarization, and Its Variation from a Decade of Observations
A joint MeerKAT and Parkes view of Omega Centauri: New TRAPUM Searches and Pulsar Timing
INAF – Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）；Australia Telescope National Facility, CSIRO（CSIRO澳大利亚望远镜国家设施）；School of Science, Western Sydney University（西悉尼大学理学院）；Space Science Division, Naval Research Laboratory（海军研究实验室空间科学部）；South African Radio Astronomy Observatory（南非射电天文观测站）
PSR J0955$-$6150 is a member of a class of eccentric MSP+He WD systems (eMSPs), whose binary evolution is poorly understood and believed to be different to that of traditional MSP+He WD systems. Measuring the masses of the stars in this system is important for testing hypotheses for the formation of eMSPs. We have carried out observations of this pulsar with the Parkes and MeerKAT radio telescopes. Our observations reveal a strong frequency evolution of this pulsar's intensity, with a spectral index ($α$) of $-3.13(2)$. The sensitivity of MeerKAT has resulted in a $>10$-fold improvement in the…
The Murchison Widefield Array (MWA), and its recently-developed Voltage Capture System (VCS), facilitates extending the low-frequency range of pulsar observations at high-time and -frequency resolution in the Southern Hemisphere, providing further information about pulsars and the ISM. We present the results of an initial time-resolved census of known pulsars using the MWA. To significantly reduce the processing load, we incoherently sum the detected powers from the 128 MWA tiles, which yields ~10% of the attainable sensitivity of the coherent sum. This preserves the large field-of-view (~450 …
Interplanetary scintillation-informed heliospheric modelling for the MeerKAT Pulsar Timing Array 4.5 yr dataset
Swinburne University of Technology（斯威本科技大学）；OzGrav: The ARC Centre of Excellence for Gravitational Wave Discovery（引力波发现ARC卓越中心）；CSIRO, Space and Astronomy（CSIRO空间与天文学部）
Discovery of a 24-millisecond pulsar in a very long orbit with the Murchison Widefield Array
International Centre for Radio Astronomy Research, Curtin University（国际射电天文研究中心，科廷大学）；Australian SKA Regional Centre (AusSRC), Curtin University（澳大利亚SKA区域中心（AusSRC），科廷大学）；Max-Planck-Institut for Radioastronomy（马克斯·普朗克射电天文研究所）
We used a dataset of archival Hubble Space Telescope images obtained through the F555W, F814W and F656N filters, to perform a complete search for objects showing $Hα$ emission in the globular cluster NGC 6397. As photometric diagnostic, we used the $(V-Hα)_0$ color excess in the $(V-Hα)_0$-$(V-I)_0$ color-color diagram. In the analysed field of view, we identified 53 $Hα$ emitters. In particular, we confirmed the optical counterpart to 20 X-ray sources (7 cataclysmic variables, 2 millisecond pulsars and 11 active binaries) and identified 33 previously unknown sources, thus significantly enlarg…
