Millisecond radio pulsars in globular clusters

AbstractOver a hundred millisecond radio pulsars (MSPs) have been observed in globular clusters (GCs), motivating theoretical studies of the formation and evolution of these sources through stellar evolution coupled to stellar dynamics. Here we study MSPs in GCs using realistic N-body simulations with our Cluster Monte Carlo code. We show that neutron stars (NSs) formed in electron-capture supernovae can be spun up through mass transfer to form MSPs. Both NS formation and spin-up through accretion are greatly enhanced through dynamical interaction processes. We find that our models for average GCs at the present day with masses ≍ 2 × 105M⊙ can produce up to 10 – 20 MSPs, while a very massive GC model with mass ≍ 106M⊙ can produce close to 100. We show that the number of MSPs is anti-correlated with the total number of stellar-mass black holes (BHs) retained in the host cluster. As a result, the number of MSPs in a GC could be used to place constraints on its BH population. Some intrinsic properties of MSP systems in our models (such as the magnetic fields and spin periods) are in good overall agreement with observations.

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Theoretical Implications of the 47 Tuc Pulsars

International Astronomical Union Colloquium ◽

10.1017/s0252921100060681 ◽

2000 ◽

Vol 177 ◽

pp. 589-594

Author(s):

Frederic A. Rasio

Keyword(s):

Globular Cluster ◽

Globular Clusters ◽

Radio Pulsars ◽

Formation And Evolution ◽

Millisecond Radio

AbstractTwenty millisecond radio pulsars have now been observed in the globular cluster 47 Tuc. This is by far the largest sample of radio pulsars known in any globular cluster. These recent observations provide a unique opportunity to re-examine theoretically the formation and evolution of recycled pulsars in globular clusters.

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Evolution of redback radio pulsars in globular clusters

Astronomy and Astrophysics ◽

10.1051/0004-6361/201628692 ◽

2017 ◽

Vol 598 ◽

pp. A35 ◽

Cited By ~ 2

Author(s):

O. G. Benvenuto ◽

M. A. De Vito ◽

J. E. Horvath

Keyword(s):

Globular Clusters ◽

Radio Pulsars

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Formation and evolution of binary and millisecond radio pulsars

Physics Reports ◽

10.1016/0370-1573(91)90064-s ◽

1991 ◽

Vol 203 (1-2) ◽

pp. 1-124 ◽

Cited By ~ 726

Author(s):

D Bhattacharya

Keyword(s):

Radio Pulsars ◽

Formation And Evolution ◽

Millisecond Radio

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Luminosities of recycled radio pulsars in globular clusters

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2011.19498.x ◽

2011 ◽

Vol 418 (1) ◽

pp. 477-489 ◽

Cited By ~ 32

Author(s):

Manjari Bagchi ◽

D. R. Lorimer ◽

Jayanth Chennamangalam

Keyword(s):

Globular Clusters ◽

Radio Pulsars

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Constraining the luminosity function parameters and population size of radio pulsars in globular clusters

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312023794 ◽

2012 ◽

Vol 8 (S291) ◽

pp. 257-260

Author(s):

Jayanth Chennamangalam ◽

D. R. Lorimer ◽

Ilya Mandel ◽

Manjari Bagchi

Keyword(s):

Population Size ◽

Globular Clusters ◽

Luminosity Function ◽

Credible Interval ◽

Diffuse Emission ◽

Radio Pulsars ◽

The Mean ◽

Log Normal ◽

Galactic Radio ◽

True Population

AbstractThe luminosity distribution of Galactic radio pulsars is believed to be log-normal in form. Applying this functional form to populations of pulsars in globular clusters, we employ Bayesian methods to explore constraints on the mean and standard deviation of the function, as well as the total number of pulsars in the cluster. Our analysis is based on an observed number of pulsars down to some limiting flux density, measurements of flux densities of individual pulsars, as well as diffuse emission from the direction of the cluster. We apply our analysis to Terzan 5 and demonstrate, under reasonable assumptions, that the number of potentially observable pulsars is in a 95.45% credible interval of 133+101−58. Beaming considerations would increase the true population size by approximately a factor of two.

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The hunt for new pulsars with the Green Bank Telescope

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312023113 ◽

2012 ◽

Vol 8 (S291) ◽

pp. 41-46

Author(s):

Ryan S. Lynch

Keyword(s):

Globular Clusters ◽

Binary Systems ◽

Radio Pulsars ◽

Large Area ◽

Pulsar Timing ◽

Drift Scan ◽

Radio Transients ◽

Pulsar Searches ◽

Green Bank Telescope ◽

Rotating Radio Transients

AbstractThe Green Bank Telescope (GBT) is the largest fully steerable radio telescope in the world and is one of our greatest tools for discovering and studying radio pulsars. Over the last decade, the GBT has successfully found over 100 new pulsars through large-area surveys. Here I discuss the two most recent—the GBT 350 MHz Drift-scan survey and the Green Bank North Celestial Cap survey. The primary science goal of both surveys is to find interesting individual pulsars, including young pulsars, rotating radio transients, exotic binary systems, and especially bright millisecond pulsars (MSPs) suitable for inclusion in Pulsar Timing Arrays, which are trying to directly detect gravitational waves. These two surveys have combined to discover 85 pulsars to date, among which are 14 MSPs and many unique and fascinating systems. I present highlights from these surveys and discuss future plans. I also discuss recent results from targeted GBT pulsar searches of globular clusters and Fermi sources.

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LUMINOSITIES OF RADIO PULSARS

International Journal of Modern Physics D ◽

10.1142/s0218271813300218 ◽

2013 ◽

Vol 22 (10) ◽

pp. 1330021 ◽

Cited By ~ 3

Author(s):

MANJARI BAGCHI

Keyword(s):

Power Law ◽

Globular Clusters ◽

Galactic Disk ◽

Intrinsic Property ◽

Magnetospheric Plasma ◽

The Other ◽

Radio Pulsars ◽

Beam Geometry ◽

Other Hand ◽

Open Questions

Luminosity is an intrinsic property of radio pulsars related to the properties of the magnetospheric plasma and the beam geometry, and inversely proportional to the observing frequency. In traditional models, luminosity has been considered as a function of the spin parameters of pulsars. On the other hand, parameter independent models like power law and lognormal have been also used to fit the observed luminosities. Some of the older studies on pulsar luminosities neglected observational biases, but all of the recent studies tried to model observational effects as accurately as possible. Luminosities of pulsars in globular clusters (GCs) and in the Galactic disk have been studied separately. Older studies concluded that these two categories of pulsars have different luminosity distributions, but the most recent study concluded that those are the same. This paper reviews all significant works on pulsar luminosities and discusses open questions.

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