Pulsars in Globular Clusters with the SKA

Hessels, J. W. T.; Possenti, A.; Bailes, M.; Bassa, Cees; Freire, P. C. C.; Lorimer, D. R.; Lynch, R.; Ransom, Scott M.; Stairs, I. H.

doi:10.22323/1.215.0047

Cited by 18 publications

(24 citation statements)

References 62 publications

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“…Globular clusters (GCs) are extraordinary factories of recycled pulsars; over the last 30 years, 146 pulsars have been discovered in Galactic GCs, with several thousands more still to be discovered (Bagchi et al 2011;Hessels et al 2015).This pulsar population is completely different from the Galactic population, with a very high fraction of pulsars with rotational periods of a few milliseconds (MSPs). One reason this happens is because GCs are very old stellar systems, so most "normal" pulsars in them have long faded into inactive neutron stars (NSs).…”

Section: Pulsars In Globular Clustersmentioning

confidence: 99%

“…We also argue that the likelihood of finding a pulsar that is very centrally concentrated is increased, which gives us the best constraints on the possible upper mass limit of a black hole. Finding these new pulsars is highly likely as the next generation of radio telescopes turn on and the sensitivity limit for finding weak pulsars is improved (Hessels et al 2015). It is also expected that search methods for finding weak pulsars will improve over time, as evidenced by the discovery of two new (but as of yet not well timed enough to include in this work) pulsars in 47 Tucanae (Pan et al 2016) and the three new pulsars discovered in (one of which does not have a timing solution) in Terzan 5 (Cadelano et al 2017).…”

Section: Black Hole Fitsmentioning

confidence: 99%

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Using Long-term Millisecond Pulsar Timing to Obtain Physical Characteristics of the Bulge Globular Cluster Terzan 5

Prager

Ransom

Freire

et al. 2017

ApJ

133

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Over the past decade the discovery of three unique stellar populations and a large number of confirmed pulsars within the globular cluster Terzan 5 has raised questions over its classification. Using the longterm radio pulsar timing of 36 millisecond pulsars in the cluster core, we provide new measurements of key physical properties of the system. As Terzan 5 is located within the galactic bulge, stellar crowding and reddening make optical and near infrared observations difficult. Pulsar accelerations, however, allow us to study the intrinsic characteristics of the cluster independent of reddening and stellar crowding and probe the mass density profile without needing to quantify the mass to light ratio. Relating the spin and orbital periods of each pulsar to the acceleration predicted by a King model, we find a core density of 1.58 +0.13 −0.13 ×10 6 M pc −3 , a core radius of 0.16−0.01 pc, a pulsar density profile n ∝ r −3.14 +0.52 −0.53 , and a total mass of M T (R ⊥ <1.0 pc) 3.0×105 M assuming a cluster distance of 5.9 kpc. Using this information we argue against Terzan 5 being a disrupted dwarf galaxy and discuss the possibility of Terzan 5 being a fragment of the Milky Way's proto-bulge. We also discuss whether low-mass pulsars were formed via electron capture supernovae or exist in a core full of heavy white dwarfs and hard binaries. Finally we provide an upper limit for the mass of a possible black hole at the core of the cluster of M BH 3 × 10 4 M .

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Section: Pulsars In Globular Clustersmentioning

confidence: 99%

Section: Black Hole Fitsmentioning

confidence: 99%

Using Long-term Millisecond Pulsar Timing to Obtain Physical Characteristics of the Bulge Globular Cluster Terzan 5

Prager

Ransom

Freire

et al. 2017

ApJ

133

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“…Currently, there are ∼ 300 MSPs (defined here as P < 30 ms) known in the Galaxy, including those associated with globular clusters (see the chapter by Hessels et al 2015). Their distribution on the sky and in the Galaxy is shown in Figure 3.…”

Section: Millisecond and Binary Pulsar Surveys With Skamentioning

confidence: 99%

Understanding the Neutron Star Population with the SKA

Tauris¹,

Kaspi²,

Breton³

et al. 2015

Proceedings of Advancing Astrophysics With the Square Kilometre Array — PoS(AASKA14)

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Since their discovery in the late 1960's the population of known neutron stars has grown to ∼2500. This sample has yielded many surprises and demonstrated that the observational properties of neutron stars are remarkably diverse. The surveys that will be performed with the SKA will produce a further tenfold increase in the number of Galactic neutron stars known. Moreover, the SKA's broad spectral coverage, sub-arraying and multi-beaming capabilities will allow us to characterise these sources with unprecedented efficiency, in turn enabling a giant leap in the understanding of their properties. We review the neutron star population and outline strategies for studying each of the growing number of diverse classes that are populating the "neutron star zoo". Questions that will be addressed by the much larger statistical samples and vastly improved timing efficiency provided by SKA include: (i) the spin period and spin-down rate distributions (and thus magnetic fields) at birth, and the associated information about the supernovae wherein they are formed; (ii) the radio pulsar-magnetar connection; (iii) the link between normal radio pulsars, intermittent pulsars and rotating radio transients; (iv) the slowest possible spin period for a radio pulsar (revealing the conditions at the pulsar death-line); (v) proper motions of pulsars (revealing supernova kick physics); (vi) the mass distribution of neutron stars; (vii) the fastest possible spin period for a recycled pulsar (constraining magnetosphere-accretion disc interactions, gravitational wave radiation and the equation-of-state); (viii) the origin of high eccentricity millisecond pulsars; (ix) the formation channels for recently identified triple systems; and finally (x) how isolated millisecond pulsars are formed. We can also expect that the first phase of the SKA (SKA1), and in particular the full SKA (SKA2), will break new ground unveiling exotic and heretofore unknown systems that will challenge our current knowledge and theories, thus fostering the development of new research areas. Some possibilities for future landmark discoveries representing significant milestones in the astrophysics of compact objects include: (i) sub-millisecond pulsars; (ii) neutron stars born as millisecond pulsars; (iii) neutron stars with masses below 1.1 or above 2.5 M ; (iv) neutron star-black hole binaries; and (v) a triple system containing a pair of neutron stars.Advancing Astrophysics with the Square Kilometre Array

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“…In future, the studies using Square Kilometre Array (SKA) may double or triple the known pulsar population [20]. For our study, finding new pulsars on various latitudes and longitudes will provide all-round interstellar medium probe with the higher reliability and accuracy.…”

Section: Discussionmentioning

confidence: 93%

“…There are no known pulsars in Andromeda Galaxy (M31) yet, but the future observations will likely discover ones [20].…”

Section: Data Setmentioning

confidence: 99%

Probing Milky Way’s hot gas halo density distribution using the dispersion measure of pulsars

2016

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A number of recent studies indicates a significant amount of ionized gas in a form of the hot gas halo around the Milky Way. The halo extends over the region of 100 kpc and may be acountable for the missing baryon mass. In this paper we calculate the contribution of the proposed halo to the dispersion measure (DM) of the pulsars. The Navarro, Frenk & White (NFW), Maller & Bullock (MB) and Feldmann, Hooper & Gnedin (FHG) density distibutions are considered for the gas halo. The data set includes pulsars with the distance known independently from the DM, e.g. pulsars in globular clusters, LMC, SMC and pulsars with known parallax. The results exclude the NFW distribution for the hot gas, while the more realistic MB and FHG models are compatible with the observed dispersion measure.

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Pulsars in Globular Clusters with the SKA

Cited by 18 publications

References 62 publications

Using Long-term Millisecond Pulsar Timing to Obtain Physical Characteristics of the Bulge Globular Cluster Terzan 5

Using Long-term Millisecond Pulsar Timing to Obtain Physical Characteristics of the Bulge Globular Cluster Terzan 5

Understanding the Neutron Star Population with the SKA

Probing Milky Way’s hot gas halo density distribution using the dispersion measure of pulsars

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