scholarly journals Eight new millisecond pulsars from the first MeerKAT globular cluster census

2021 ◽  
Vol 504 (1) ◽  
pp. 1407-1426
Author(s):  
A Ridolfi ◽  
T Gautam ◽  
P C C Freire ◽  
S M Ransom ◽  
S J Buchner ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Total Mass ◽  
Globular Clusters ◽  
The Other ◽  
Telescope Array ◽  
Millisecond Pulsars ◽  
The Core ◽  
Binary Pulsars ◽  
Low Mass ◽  
Large Eccentricity

ABSTRACT 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 (GCs). 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 (≲0.32 d), 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 d) orbits, with companions that are likely to be white dwarfs or neutron stars. NGC 6624G has a large eccentricity of e ≃ 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 Mtot = 2.65 ± 0.07 M⊙. Likewise, for Ter 5 an, with e ≃ 0.0066, we obtain Mtot = 2.97 ± 0.52 M⊙. 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 ∼2 arcmin in radius around the centre 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 GC pulsar survey.

scholarly journals Formation of Binary and Millisecond Pulsars: Puzzles and Possible Solutions

2012 ◽  
Vol 8 (S291) ◽  
pp. 499-501
Author(s):  
Yong Shao ◽  
Xiang-Dong Li
Keyword(s):  
Mass Transfer ◽  
Neutron Stars ◽  
Systematic Study ◽  
Brown Dwarf ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Common Envelope ◽  
Binary Pulsars ◽  
Low Mass ◽  
X Ray Binaries

AbstractWe present a systematic study of the evolution of intermediate- and low-mass X-ray binaries. Our calculations suggest that millisecond binary pulsars in wide orbits might have neutron stars born massive, or been formed through mass transfer driven by planet/brown dwarf-involved common envelope evolution.

scholarly journals XMM-Newton and Chandra Observations of Neutron Stars and Cataclysmic Variables in the Globular Cluster NGC 2808

2007 ◽  
Vol 3 (S246) ◽  
pp. 373-374
Author(s):  
M. Servillat ◽  
N. A. Webb ◽  
D. Barret ◽  
R. Cornelisse ◽  
A. Dieball ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Cataclysmic Variables ◽  
Cataclysmic Variable ◽  
Specific Nature ◽  
X Ray ◽  
The Core ◽  
Show Evidence ◽  
Low Mass

AbstractWe report on XMM-Newton and Chandra observations of the globular cluster NGC 2808. We detect one quiescent low mass X-ray binary of the 3±1 expected, if these systems are formed through encounters, and we show evidence for the presence of 20±10 bright cataclysmic variables in the core with a luminosity above 4×1031 erg s−1. We also review the specific nature of cataclysmic variables in globular clusters with reference to recent VLT/FORS1 observations of a cataclysmic variable in M 22.

scholarly journals Pulsars in Globular Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 291-300 ◽  
Author(s):  
Scott M. Ransom
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Globular Clusters ◽  
Main Sequence ◽  
Galactic Disk ◽  
Nuclear Density ◽  
Millisecond Pulsars ◽  
Eccentric Orbits ◽  
The Masses ◽  
Current Record

AbstractGlobular clusters produce orders of magnitude more millisecond pulsars per unit mass than the Galactic disk. Since the first cluster pulsar was uncovered 20 years ago, at least 138 have been identified – most of which are binary millisecond pulsars. Because their origins involve stellar encounters, many of the systems are exotic objects that would never be observed in the Galactic disk. Examples include pulsar-main sequence binaries, extremely rapid rotators (including the current record holder), and millisecond pulsars in highly eccentric orbits. These systems are allowing new probes of the interstellar medium, the equation of state of material at supra-nuclear density, the masses of neutron stars, and globular cluster dynamics.

scholarly journals Core-hydrogen-burning RSGs in the early globular clusters

2015 ◽  
Vol 11 (A29B) ◽  
pp. 473-473
Author(s):  
Dorottya Szécsi ◽  
Jonathan Mackey ◽  
Norbert Langer
Keyword(s):  
Globular Clusters ◽  
Stellar Population ◽  
Massive Stars ◽  
Shell Formation ◽  
Low Mass Stars ◽  
Hydrogen Burning ◽  
The Core ◽  
Anomalous Surface ◽  
Low Metallicity ◽  
Low Mass

AbstractThe first stellar generation in galactic globular clusters contained massive low-metallicity stars (Charbonnel et al. 2014). We modelled the evolution of this massive stellar population and found that such stars with masses 100-600 M⊙ evolve into cool RSGs (Szécsi et al. 2015). These RSGs spend not only the core-He-burning phase but even the last few 105 years of the core-H-burning phase on the SG branch. Due to the presence of hot massive stars in the cluster at the same time, we show that the RSG wind is trapped into photoionization confined shells (Mackey et al. 2014). We simulated the shell formation around such RSGs and find them to become gravitationally unstable (Szécsi et al. 2016). We propose a scenario in which these shells are responsible for the formation of the second generation low-mass stars in globular clusters with anomalous surface abundances.

scholarly journals A decade of transitional millisecond pulsars

2017 ◽  
Vol 13 (S337) ◽  
pp. 47-51 ◽  
Author(s):  
Amruta Jaodand ◽  
Jason W. T. Hessels ◽  
Anne Archibald
Keyword(s):  
Neutron Stars ◽  
Millisecond Pulsar ◽  
Physical Processes ◽  
Recycling Process ◽  
Millisecond Pulsars ◽  
X Ray ◽  
System A ◽  
Multi Wavelength ◽  
Low Mass

AbstractTransitional millisecond pulsars (tMSPs), which are systems that harbor a pulsar in the throes of the recycling process, have emerged as a new source class since the discovery of the first such system a decade ago. These systems switch between accretion-powered low-mass X-ray binary (LMXB) and rotation-powered radio millisecond pulsar (RMSP) states, and provide exciting avenues to understand the physical processes that spin-up neutron stars to millisecond periods. During the last decade, three tMSPs, as well as a candidate source, have been extensively probed using systematic, multi-wavelength campaigns. Here we review the observational highlights from these campaigns and our general understanding of tMSPs.

scholarly journals MEASUREMENT OF THE RADIUS OF NEUTRON STARS WITH HIGH SIGNAL-TO-NOISE QUIESCENT LOW-MASS X-RAY BINARIES IN GLOBULAR CLUSTERS

2013 ◽  
Vol 772 (1) ◽  
pp. 7 ◽  
Author(s):  
Sebastien Guillot ◽  
Mathieu Servillat ◽  
Natalie A. Webb ◽  
Robert E. Rutledge
Keyword(s):  
Neutron Stars ◽  
Globular Clusters ◽  
High Signal ◽  
Signal To Noise ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

scholarly journals The Orbital Eccentricities of Binary Millisecond Pulsars in Globular Clusters

1996 ◽  
Vol 174 ◽  
pp. 383-383
Author(s):  
Frederic A. Rasio ◽  
Douglas C. Heggie
Keyword(s):  
Cross Section ◽  
Power Law ◽  
Globular Clusters ◽  
Major Axis ◽  
Semi Major Axis ◽  
Millisecond Pulsars ◽  
Numerical Integrations ◽  
Order Of Magnitude ◽  
Low Mass ◽  
Analytical Perturbation

Low-mass binary millisecond pulsars are born with very small orbital eccentricities, typically of order ei ∼ 10−6−10−3. In globular clusters, however, higher eccentricities ef ≫ ei can be induced by dynamical interactions with passing stars. Using both analytical perturbation calculations and numerical integrations, we have shown (Heggie & Rasio 1996) that the cross section for this process is much larger than previously estimated. This is because, even for initially circular binaries, the induced eccentricity ef for an encounter with pericentre separation rp beyond a few times the binary semi-major axis a declines only as a power-law, ef ∝ (rp/a)−5/2, and not as an exponential. We find that all currently known low-mass binary millisecond pulsars in globular clusters must have been affected by interactions, with their current eccentricities being at least an order of magnitude larger than at birth (Rasio & Heggie 1995).

scholarly journals The death line of millisecond pulsars

1996 ◽  
Vol 160 ◽  
pp. 189-190
Author(s):  
Claes-Ingvar Björnsson
Keyword(s):  
Neutron Stars ◽  
Birth Rate ◽  
Large Fraction ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Low Mass

AbstractThe distribution of millisecond pulsars, just as normal pulsars, is affected by a death line. Since a large fraction of millisecond pulsars lie close to the derived death line, a significant number of neutron stars may exist which are not observed as millisecond pulsars. This makes the birth rate discrepancy between millisecond pulsars and their assumed low mass x-ray binary progenitors more acute.

scholarly journals Evolution of binaries with compact objects in globular clusters

2014 ◽  
Vol 10 (S312) ◽  
pp. 203-212
Author(s):  
Natalia Ivanova
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Stars ◽  
Globular Clusters ◽  
Compact Objects ◽  
Stellar Systems ◽  
Stellar Objects ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

AbstractDynamical interactions that take place between objects in dense stellar systems lead to frequent formation of exotic stellar objects, unusual binaries, and systems of higher multiplicity. They are most important for the formation of binaries with neutron stars and black holes, which are usually observationally revealed in mass-transferring binaries. Here we review the current understanding of compact object's retention, of the metallicity dependence on the formation of low-mass X-ray binaries with neutron stars, and how mass-transferring binaries with a black hole and a white dwarf can be formed. We discuss as well one old unsolved puzzle and two new puzzles posed by recent observations: what descendants do ultra-compact X-ray binaries produce, how are very compact triples formed, and how can black hole low-mass X-ray binaries acquire non-degenerate companions?

scholarly journals The first binary pulsars and what they told us about binary evolution

2017 ◽  
Vol 13 (S337) ◽  
pp. 37-42
Author(s):  
Dipankar Bhattacharya
Keyword(s):  
Neutron Stars ◽  
Early Development ◽  
Binary Systems ◽  
Historical Review ◽  
Binary Pulsars ◽  
Low Mass ◽  
Pulsar Wind ◽  
Binary Evolution ◽  
The Impact

AbstractThe first few binary pulsars revealed the richness of evolution possible in binary systems containing neutron stars. Products of different evolutionary routes, in high and low mass binaries, as well as examples of evolution affected by the pulsar wind were among the first ten objects discovered. This article presents a historical review of the impact of binary pulsars on the early development of ideas regarding the evolution of neutron stars in binary systems.

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