Proper motions of open star clusters and the rotation rate of the galaxy

Локтин, А. В.; Beshenov, G. V.

doi:10.1134/1.1538491

Cited by 54 publications

(43 citation statements)

References 4 publications

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“…On the other hand, the open cluster in the centre of region #2 is NGC 6604, which can be found in the WEBDA catalogue, with a distance of 1.7 kpc, and an age of ∼6 Myr. Loktin & Beshenov (2003) measured an average proper motion of this cluster, formed by ∼97 stars, and obtained −0.66 ± 0.19 and −0.88 ±0.17 mas yr −1 in right ascension and declination, respectively, as well as the distance quoted in the WEBDA database. Recently, Dambis et al (2001) set a parallax of 0.59 mas, corresponding to a distance from the Sun of 1.7 kpc, and an age of 4-5 Myr.…”

Section: The Origin Of Ls 5039 and Psr J1825−1446mentioning

confidence: 99%

On the origin of LS 5039 and PSR J1825−1446

Moldón

Ribó

Paredes

et al. 2012

A&A

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Context. The gamma-ray binary LS 5039 and the isolated pulsar PSR J1825−1446 were proposed to have been formed in the supernova remnant (SNR) G016.8−01.1. Aims. We aim to obtain the Galactic trajectory of LS 5039 and PSR J1825−1446 to find their origin in the Galaxy, and in particular to check their association with SNR G016.8−01.1 to restrict their age. Methods. By means of radio and optical observations we obtained the proper motion and the space velocity of the sources. Results. The proper motion of PSR J1825−1446 corresponds to a transverse space velocity of 690 km s −1 at a distance of 5 kpc. Its Galactic velocity at different distances is not compatible with the expected Galactic rotation. The velocity and characteristic age of PSR J1825−1446 make it incompatible with SNR G016.8−01.1. There are no clear OB associations or SNRs crossing the past trajectory of PSR J1825−1446. We estimate the age of the pulsar to be 80-245 kyr, which is compatible with its characteristic age. The proper motion of LS 5039 is μ α cos δ = 7.09 and μ δ = −8.82 mas yr −1 . The association of LS 5039 with SNR G016.8−01.1 is unlikely, although we cannot discard it. The system would have had to be formed in the association Ser OB2 (at 2.0 kpc) if the age of the system is 1.0-1.2 Myr, or in the association Sct OB3 (distance 1.5-2 kpc) for an age of 0.1-0.2 Myr. If the system were not formed close to Ser OB2, the pseudo-synchronization of the orbit would be unlikely. Conclusions. PSR J1825−1446 is a high-velocity isolated pulsar ejected from the Galaxy. The distance to LS 5039, which needs to be constrained by future astrometric missions such as Gaia, is a key parameter for restricting its origin and age.

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Section: The Origin Of Ls 5039 and Psr J1825−1446mentioning

confidence: 99%

On the origin of LS 5039 and PSR J1825−1446

Moldón

Ribó

Paredes

et al. 2012

A&A

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“…One example is the determination of proper motions for cluster stars, as done by Loktin & Beshenov (2003) for Trumpler 1, where the author determines the proper motion of the cluster from measurements of 12 stars. However, the author does not provide the individual data for the stars and therefore it could not be used to assign weights to the observations.…”

Section: Trumplermentioning

confidence: 99%

Fitting isochrones to open cluster photometric data

Monteiro¹,

Dias²,

Caetano³

2010

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We present a new technique to fit color-magnitude diagrams of open clusters based on the cross-entropy global optimization algorithm. The method uses theoretical isochrones available in the literature and maximizes a weighted likelihood function based on distances measured in the color-magnitude space. The weights are obtained through a non parametric technique that takes into account the star distance to the observed center of the cluster, observed magnitude uncertainties, the stellar density profile of the cluster among others. The parameters determined simultaneously are distance, reddening, age and metallicity. The method takes binary fraction into account and uses a Monte-Carlo approach to obtain uncertainties on the determined parameters for the cluster by running the fitting algorithm many times with a re-sampled data set through a bootstrapping procedure. We present results for 9 well studied open clusters, based on 15 distinct data sets, and show that the results are consistent with previous studies. The method is shown to be reliable and free of the subjectivity of most previous visual isochrone fitting techniques.

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“…From D07, a Tycho-2 determination for the proper motion of this object was obtained by Loktin & Beshenov (2003) during a study of the rotation rate of the Galaxy (−0.06 ± 0.99; −4.38 ± 1.78) mas yr −1 . Nonetheless, no list has been published with individual membership probabilities, so one cannot explore the connection between the cluster and the shell on a star by star basis.…”

Section: Berkeley 82mentioning

confidence: 99%

Kinematic parameters and membership probabilities of open clusters in the Bordeaux PM2000 catalogue

Krone-Martins

Soubiran

Ducourant

et al. 2010

A&A

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Aims. We derive lists of proper-motions and kinematic membership probabilities for 49 open clusters and possible open clusters in the zone of the Bordeaux PM2000 proper motion catalogue (+11 • ≤ δ ≤ +18 • ). We test different parametrisations of the proper motion and position distribution functions and select the most successful one. In the light of those results, we analyse some objects individually. Methods. We differenciate between cluster and field member stars, and assign membership probabilities, by applying a new and fully automated method based on both parametrisations of the proper motion and position distribution functions, and genetic algorithm optimization heuristics associated with a derivative-based hill climbing algorithm for the likelihood optimization.Results. We present a catalogue comprising kinematic parameters and associated membership probability lists for 49 open clusters and possible open clusters in the Bordeaux PM2000 catalogue region. We note that this is the first determination of proper motions for five open clusters. We confirm the non-existence of two kinematic populations in the region of 15 previously suspected non-existent objects.

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Proper motions of open star clusters and the rotation rate of the galaxy

Cited by 54 publications

References 4 publications

On the origin of LS 5039 and PSR J1825−1446

On the origin of LS 5039 and PSR J1825−1446

Fitting isochrones to open cluster photometric data

Kinematic parameters and membership probabilities of open clusters in the Bordeaux PM2000 catalogue

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