Neutron stars and millisecond pulsars from accretion-induced collapse in globular clusters

1990 ◽  
Vol 353 ◽  
pp. 159 ◽  
Author(s):  
Charles D. Bailyn ◽  
Jonathan E. Grindlay
2007 ◽  
Vol 3 (S246) ◽  
pp. 291-300 ◽  
Author(s):  
Scott M. Ransom

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.


2021 ◽  
Vol 504 (1) ◽  
pp. 1407-1426
Author(s):  
A Ridolfi ◽  
T Gautam ◽  
P C C Freire ◽  
S M Ransom ◽  
S J Buchner ◽  
...  

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.


1996 ◽  
Vol 174 ◽  
pp. 347-348
Author(s):  
G.A. Drukier

Although globular clusters are known to contain a population of neutron stars, the recent finding by Lyne and Lorimer (1994) that field neutron stars are formed with a mean “kick” velocity of 450 km s−1 implies that globular clusters would retain very few neutron stars. The number of neutron stars is important when discussing cluster mortality and the formation rate of millisecond pulsars.


1996 ◽  
Vol 165 ◽  
pp. 57-64
Author(s):  
Pranab Ghosh

In this symposium, I have been given the task of summarizing our current understanding of the evolutionary history of spin periods of the neutron stars that we now see as binary and millisecond pulsars, i.e., recycled pulsars. We believe that a newborn, fast-spinning neutron star (with a rather high magnetic field ∼1011–1013 G) in a binary system first operates as a spin-powered pulsar, subsequently as an accretion-powered pulsar when accretion begins after the pulsar has been spun down adequately, and finally as a spin-powered pulsar for the second time after having been recycled to become a very fast-rotating neutron star (with a rather low magnetic field ∼108–1011 G) (see Ghosh 1994a, b, hereafter G94a, b).


2000 ◽  
Vol 195 ◽  
pp. 49-60
Author(s):  
W. Becker

Recent X-ray observatories such as ROSAT, ASCA, RXTE, BeppoSAX, and Chandra have achieved important progress in neutron star and pulsar astronomy. The identification of Geminga as a rotation-powered pulsar, the discovery of X-ray emission from millisecond pulsars, and the identification of cooling neutron stars are only a few of the fascinating results. In the following, I will give a brief review on the X-ray emission properties of rotation-powered pulsars and their wind nebulae.


2018 ◽  
Vol 476 (1) ◽  
pp. 421-435 ◽  
Author(s):  
A W Steiner ◽  
C O Heinke ◽  
S Bogdanov ◽  
C K Li ◽  
W C G Ho ◽  
...  

1996 ◽  
Vol 165 ◽  
pp. 389-400
Author(s):  
Helen M. Johnston ◽  
Frank Verbunt ◽  
Günther Hasinger ◽  
Wolfram Bunk

X-ray sources in globular clusters fall into two categories: the “bright” sources, with LX ∼ 1036-1038 erg s−1, and the “dim” sources, with LX ≲ 1034.5 erg s−1. The bright sources are clearly associated with accreting neutron stars in binary systems. The nature of the dim sources, however, remains in doubt. We review recent observations of globular-cluster X-ray sources with the ROSAT satellite. ROSAT detected bright sources in M31 globular clusters and greatly increased the number of dim sources known in galactic globular clusters. We discuss what these new observations have taught us about the distribution and nature of such sources, their spectral properties, and their underlying luminosity function.


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