scholarly journals Low‐Mass X‐Ray Binaries in Six Elliptical Galaxies: Connection to Globular Clusters

2006 ◽  
Vol 647 (1) ◽  
pp. 276-292 ◽  
Author(s):  
Eunhyeuk Kim ◽  
Dong‐Woo Kim ◽  
Giuseppina Fabbiano ◽  
Myung Gyoon Lee ◽  
Hong Soo Park ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Elliptical Galaxies ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

scholarly journals X-ray sources in Galactic globular clusters and old open clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 367-376
Author(s):  
Maureen van den Berg
Keyword(s):  
Globular Clusters ◽  
Cataclysmic Variables ◽  
Star Clusters ◽  
Open Clusters ◽  
Encounter Rate ◽  
X Ray ◽  
Low Mass ◽  
New Perspective ◽  
X Ray Binaries ◽  
Cluster Age

AbstractThe features and make up of the population of X-ray sources in Galactic star clusters reflect the properties of the underlying stellar environment. Cluster age, mass, stellar encounter rate, binary frequency, metallicity, and maybe other properties as well, determine to what extent we can expect a contribution to the cluster X-ray emission from low-mass X-ray binaries, millisecond pulsars, cataclysmic variables, and magnetically active binaries. Sensitive X-ray observations withXMM-Newton and certainlyChandra have yielded new insights into the nature of individual sources and the effects of dynamical encounters. They have also provided a new perspective on the collective X-ray properties of clusters, in which the X-ray emissivities of globular clusters and old open clusters can be compared to each other and to those of other environments. I will review our current understanding of cluster X-ray sources, focusing on star clusters older than about 1 Gyr, illustrated with recent results.

scholarly journals The Globular Cluster Population of X-ray Binaries

1987 ◽  
Vol 125 ◽  
pp. 187-197 ◽  
Author(s):  
Frank Verbunt ◽  
Piet Hut
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Mass Function ◽  
Initial Mass Function ◽  
Encounter Rate ◽  
Formation Mechanisms ◽  
Main Sequence Stars ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

We discuss formation mechanisms for low-mass X-ray binaries in globular clusters. We apply the most efficient mechanism, tidal capture in close two-body encounters between neutron and main-sequence stars, to the clusters of our galaxy. The observed number of X-ray sources in these can be explained if the birth velocities of neutron stars are higher than estimated from velocity measurements of radiopulsars, or if the initial mass function steepens at high masses. We perform a statistical test on the distribution of X-ray sources with respect to the number of close encounters in globular clusters, and find satisfactory agreement between the tidal capture theory and observation, apart from the presence of low-mass X-ray binaries in four clusters with a very low encounter rate: Ter 1, Ter 2, Gr 1 and NGC 6712.EXOSAT observations indicate that some dim globular cluster sources may be less luminous than hitherto assumed, and support the view that the brighter dim sources may be soft X-ray transients in quiescence.

scholarly journals Observational Evidence for the Origin of X-ray Sources in Globular Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 301-310 ◽  
Author(s):  
Frank Verbunt ◽  
Dave Pooley ◽  
Cees Bassa
Keyword(s):  
Statistical Method ◽  
Globular Clusters ◽  
Cataclysmic Variables ◽  
Observational Evidence ◽  
X Ray ◽  
Cluster Mass ◽  
Low Mass ◽  
Optical Identifications ◽  
X Ray Binaries

AbstractLow-mass X-ray binaries, recycled pulsars, cataclysmic variables and magnetically active binaries are observed as X-ray sources in globular clusters. We discuss the classification of these systems, and find that some presumed active binaries are brighter than expected. We discuss a new statistical method to determine from observations how the formation of X-ray sources depends on the number of stellar encounters and/or on the cluster mass. We show that cluster mass is not a proxy for the encounter number, and that optical identifications are essential in proving the presence of primordial binaries among the low-luminosity X-ray sources.

scholarly journals Probing the Formation of Low‐Mass X‐Ray Binaries in Globular Clusters and the Field

2007 ◽  
Vol 662 (1) ◽  
pp. 525-543 ◽  
Author(s):  
Arunav Kundu ◽  
Thomas J. Maccarone ◽  
Stephen E. Zepf
Keyword(s):  
Globular Clusters ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

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 Low-Mass X-Ray Binaries and Globular Clusters in Centaurus A

2007 ◽  
Vol 671 (2) ◽  
pp. L117-L120 ◽  
Author(s):  
Andrés Jordán ◽  
Gregory R. Sivakoff ◽  
Dean E. McLaughlin ◽  
John P. Blakeslee ◽  
Daniel A. Evans ◽  
...  
Keyword(s):  
Globular Clusters ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries ◽  
Centaurus A

scholarly journals Constraining the duty cycle of transient low-mass X-ray binaries through simulations

2019 ◽  
Vol 488 (2) ◽  
pp. 2767-2779 ◽  
Author(s):  
D Carbone ◽  
R Wijnands
Keyword(s):  
Duty Cycle ◽  
Globular Clusters ◽  
Galactic Centre ◽  
Data Set ◽  
X Ray ◽  
Long Period ◽  
Transient Sources ◽  
Low Mass ◽  
The One ◽  
X Ray Binaries

Abstract We performed simulations of a large number of so-called very faint X-ray transient sources from surveys obtained using the X-ray telescope aboard the Neil Gehrels Swift Observatory on two Galactic globular clusters, and the Galactic Centre. We calculated the ratio between the duty cycle (DC) we input in our simulations and the one we measure after the simulations. We found that fluctuations in outburst duration and recurrence times affect our estimation of the DC more than non-detected outbursts. This biases our measures to overestimate the simulated DC of sources. Moreover, we determined that compact surveys are necessary to detect outbursts with short duration because they could fall in gaps between observations, if such gaps are longer than their duration. On the other hand, long surveys are necessary to detect sources with low DC because the smallest DC a survey can observe is given by the ratio between the shortest outburst duration and the total length of the survey. If one has a limited amount of observing time, these two effects are competing, and a compromise is required which is set by the goals of the proposed survey. We have also performed simulations with several artificial survey strategies in order to evaluate the optimal observing campaign aimed at detecting transients as well as at having the most accurate estimates of the DC. As expected, the best campaign would be a regular and dense monitoring that extends for a very long period. The closest real example of such a data set is the monitoring of the Galactic Centre.

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