Observations of 20 Millisecond Pulsars in 47 Tucanae at 20 Centimeters

Camilo, F.; Lorimer, D. R.; Freire, P. C. C.; Lyne, A. G.; Manchester, R. N.

doi:10.1086/308859

Cited by 259 publications

(387 citation statements)

References 52 publications

(70 reference statements)

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“…Indeed, the radio observations find a large population of binary millisecond pulsars in 47 Tuc (Manchester et al 1991;Camilo et al 2000), many of which appear to have low-mass white dwarf companions (Rasio et al 2000). In one case, 47 Tuc U, the NF companion has been detected optically , for which we estimate a mass '0.14-0.2 M and an age less than 10 8 yr, even for a large hydrogen surface layer.…”

Section: Application To 47 Tucmentioning

confidence: 71%

“…In what follows, we discuss our expectations for the (currently undetected) NF population in 47 Tuc. The attraction of this cluster is the rich data set spanning X-ray (Grindlay et al 2001a), UV (Ferraro et al 2001b;Knigge et al 2002), optical (Gilliland et al 2000), and radio (Camilo et al 2000) wavelengths. 47 Tuc is also interesting in that it is a dense, pre-core-collapse cluster and somewhat more massive than NGC 6397.…”

Section: Application To 47 Tucmentioning

confidence: 99%

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Helium Core White Dwarfs in Globular Clusters

Hansen

Kalogera

Rasio

2003

ApJ

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We examine the theoretical implications of a population of low-mass helium core white dwarfs in globular clusters. In particular, we focus on the observed population in the core of NGC 6397, where several low-mass white dwarf candidates have been identified as '' nonflickerers '' by Cool and collaborators. Age and mass estimates from cooling models, combined with dynamical and evolutionary considerations, lead us to infer that the dark binary companions are C/O white dwarfs rather than neutron stars. Furthermore, we find that the progenitor binaries very likely underwent an exchange interaction within the last 10 9 yr. We examine the prospects for detecting a similar population in other globular clusters, with particular attention to the case of 47 Tuc.

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Section: Application To 47 Tucmentioning

confidence: 71%

Section: Application To 47 Tucmentioning

confidence: 99%

Helium Core White Dwarfs in Globular Clusters

Hansen

Kalogera

Rasio

2003

ApJ

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“…In particular, the 11 known MSPs in the cluster 47 Tuc (Manchester et al 1991;Robinson et al 1995) have been recently increased to 20 (Camilo et al 2000, hereafter CLF00), with 16 of these currently having accurate (milliarcsecond) timing positions (Freire et al 2001a;Freire 2001). These enable studies of the cluster's gravitational potential well (Freire et al 2001a) and of the intracluster medium (Freire et al 2001b).…”

Section: Introductionmentioning

confidence: 99%

A Millisecond Pulsar Optical Counterpart with Large‐Amplitude Variability in the Globular Cluster 47 Tucanae

Edmonds

Gilliland

Camilo

et al. 2002

ApJ

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Using extensive Hubble Space Telescope imaging, combined with Chandra X-ray and Parkes radio data, we have detected the optical binary companion to a second millisecond pulsar (MSP) in the globular cluster 47 Tucanae. This faint (V ¼ 22:3) blue (VÀI = 0.7) star shows a large-amplitude (60%-70%) sinusoidal variation in both V and I. The period (3.19066 hr) and phase of the variation match those of the MSP 47 Tuc W (which does not have an accurate radio timing position) to within 0.5 s and 1.2 minutes, respectively, well within the 1 errors. The phase dependence of the intensity and color implies that heating of a tidally locked companion causes the observed variations. The eclipsing nature of this MSP in the radio, combined with the relatively large companion mass (greater than 0.13 M ) and the companion's position in the color-magnitude diagram, suggests that the companion is a main-sequence star, a rare circumstance for an MSP companion. This system is likely to have had a complex evolution and represents an interesting case study in MSP irradiation of a close companion. We present evidence for another optical variable with similar properties to the companion of 47 Tuc W. This variable also may be an MSP companion, although no radio counterpart has yet been detected.

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“…47 Tuc is also a subject of intense scrutiny due to the large number of MSPs residing within the cluster. There have been 25 MSPs discovered so far using the 64-m Parkes Radio Telescope (Manchester et al 1990(Manchester et al , 1991Robinson et al 1995;Camilo et al 2000;Pan et al 2016;Freire et al 2017), with radio timing positions known for 23 of them (Freire et al 2001b(Freire et al , 2003Pan et al 2016;Ridolfi et al 2016;Freire et al 2017, Freire & Ridolfi 2017.…”

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confidence: 99%

Chandra studies of the globular cluster 47 Tucanae: a deeper X-ray source catalogue, five new X-ray counterparts to millisecond radio pulsars and new constraints to r-mode instability window

Bhattacharya

Heinke

Chugunov

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We combined Chandra ACIS observations of the globular cluster 47 Tucanae (hereafter, 47 Tuc) from 2000, 2002, and 2014-15 to create a deeper X-ray source list, and study some of the faint radio millisecond pulsars (MSPs) present in this cluster. We have detected 370 X-ray sources within the half-mass radius (2 .79) of the cluster, 81 of which are newly identified, by including new data and using improved source detection techniques. The majority of the newly identified sources are in the crowded core region, indicating cluster membership. We associate five of the new X-ray sources with chromospherically active BY Dra or W UMa variables identified by Albrow et al. (2001). We present alternative positions derived from two methods, centroiding and image reconstruction, for faint, crowded sources. We are able to extract X-ray spectra of the recently discovered MSPs 47 Tuc aa, 47 Tuc ab, the newly timed MSP 47 Tuc Z, and the newly resolved MSPs 47 Tuc S and 47 Tuc F. Generally, they are well fit by black body or neutron star atmosphere models, with temperatures, luminosities and emitting radii similar to those of other known MSPs in 47 Tuc, though 47 Tuc aa and 47 Tuc ab reach lower X-ray luminosities. We limit X-ray emission from the full surface of the rapidly spinning (542 Hz) MSP 47 Tuc aa, and use this limit to put an upper bound for amplitude of r-mode oscillations in this pulsar as α < 2.5 × 10 −9 and constrain the shape of the r-mode instability window.

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Observations of 20 Millisecond Pulsars in 47 Tucanae at 20 Centimeters

Cited by 259 publications

References 52 publications

Helium Core White Dwarfs in Globular Clusters

Helium Core White Dwarfs in Globular Clusters

A Millisecond Pulsar Optical Counterpart with Large‐Amplitude Variability in the Globular Cluster 47 Tucanae

Chandra studies of the globular cluster 47 Tucanae: a deeper X-ray source catalogue, five new X-ray counterparts to millisecond radio pulsars and new constraints to r-mode instability window

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