scholarly journals Membership and Internal Motions of Faint Stars in the Globular Cluster M 3

1994 ◽  
Vol 161 ◽  
pp. 461-463
Author(s):  
R.-D. Scholz ◽  
N.V. Kharchenko
Keyword(s):  
Globular Cluster ◽  
Proper Motion ◽  
Stepwise Regression ◽  
Regression Method ◽  
Proper Motions ◽  
Internal Motions ◽  
Motion Study

A proper motion study from Tautenburg Schmidt plates is presented for the globular cluster M 3 and its vicinity. The plates were scanned with the Automated Photographic Measuring (APM) system in Cambridge (UK). With a limiting magnitude of B = 21, proper motions of 2 to 3 mas/yr accuracy have been obtained for stars with B < 19. The proper motions were determined applying a stepwise regression method with 3rd order polynomials in the plate-to-plate solutions with about 2000 reference galaxies. We used the results for the determination of membership probabilities and looked for internal motions of M 3.

scholarly journals Determination of Absolute Proper Motions by Use of Automated Measurements of Tautenburg Plates

1990 ◽  
Vol 141 ◽  
pp. 451-452
Author(s):  
R.-D. Scholz
Keyword(s):  
Globular Cluster ◽  
Proper Motion ◽  
Proper Motions ◽  
Automated Measurements ◽  
The Absolute ◽  
Good Agreement

From measurements of Tautenburg Schmidt plates with the APM in Cambridge positional accuracies per plate of 0.″05 for stars and of 0.″10 for galaxies were achieved. With 0.″3/100a accuracy in a single stellar proper motion we obtained the absolute proper motion of the M3 globular cluster in good agreement between the two pairs of plates used.

scholarly journals Absolute Proper and Space Motion of the Globular Cluster M2

1994 ◽  
Vol 161 ◽  
pp. 464-466
Author(s):  
M. Geffert ◽  
C. Forner ◽  
M. Hiesgen ◽  
A.R. Klemola
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Milky Way ◽  
Reference Frames ◽  
Proper Motions ◽  
The Past ◽  
Motion Study ◽  
Space Motion ◽  
First Results

Space motions of globular clusters are important for the understanding of the kinematics and chemical evolution of the Milky Way. The greatest problem for the determination of the space motions of the globular clusters arises from the difficulties of getting absolute proper motions. In the past these were determined using classical stellar reference frames, modelling of the non-cluster stars in the field and extragalactic objects in the region of the cluster (see e.g. Cudworth & Hanson 1993; Geffert et al. 1993 for references). However, as shown for M 15 and M 3 (Geffert et al. 1993; Tucholke et al. 1993), the results based on different methods for deriving the absolute proper motions differ by up to yrs. In order to get a more complete view of the differences between the various methods it is therefore very interesting to get absolute proper motions based on all three methods for further objects. We present here the first results of a new proper motion study of the globular cluster M 2.

scholarly journals A Space Motion Study of the Globular Cluster M13

2002 ◽  
Vol 207 ◽  
pp. 119-121
Author(s):  
L. Chen ◽  
J.J. Wang ◽  
J.L. Zhao
Keyword(s):  
Globular Cluster ◽  
Proper Motion ◽  
Proper Motions ◽  
Velocity Data ◽  
Motion Data ◽  
Motion Study ◽  
Space Motion ◽  
The Galaxy ◽  
Radial Velocity Data ◽  
Right Ascension

Positions and absolute proper motions of 264 stars in the field of about 70′ × 70′ around the globular cluster M13 were determined. In the astrometric reduction, three early and three late epoch plates taken with the 40cm refractor at Shensan, Shanghai, China, were used, with the time baseline of 73 years. The reduction was done using the central overlapping algorithm, with 5 Hipparcos stars and 38 Tycho-2 stars used as reference stars. Based on the reduced proper motion data, the membership probabilities of the sample stars were determined. An absolute proper motion of the cluster of 1.49 ± 0.36 mas yr−1 in right ascension and 3.06±0.35 mas yr−1 in declination was obtained. From this proper motion, together with distance and radial velocity data, we derived the space motion of M13 and via numerical integration also the orbit of the cluster in the Galaxy.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

scholarly journals Proper motions in the Galactic bulge: Plaut's window

2007 ◽  
Vol 3 (S245) ◽  
pp. 351-354
Author(s):  
Katherine Vieira ◽  
Dana Cassetti-Dinescu ◽  
René A. Méndez ◽  
R. Michael Rich ◽  
Terrence M. Girard ◽  
...  
Keyword(s):  
Proper Motion ◽  
Galactic Rotation ◽  
Red Giants ◽  
Proper Motions ◽  
Motion Study ◽  
Solar Motion ◽  
Two Samples ◽  
Red Clump ◽  
Good Agreement ◽  
Peak Value

AbstractA proper motion study of a field of 20′ × 20′ inside Plaut's low extinction window (l,b)=(0o, −8o), has been completed. Relative proper motions and photographicBVphotometry have been derived for ~ 21,000 stars reaching toV~ 20.5 mag, based on the astrometric reduction of 43 photographic plates, spanning over 21 years of epoch difference. Proper motion errors are typically 1 mas yr−1. Cross-referencing with the 2MASS catalog yielded a sample of ~ 8700 stars, from which predominantly disk and bulge subsamples were selected photometrically from theJHcolor-magnitude diagram. The two samples exhibited different proper-motion distributions, with the disk displaying the expected reflex solar motion. Galactic rotation was also detected for stars between ~2 and ~3 kpc from us. The bulge sample, represented by red giants, has an intrinsic proper motion dispersion of (σl, σb) = (3.39, 2.91)±(0.11, 0.09) mas yr−1, which is in good agreement with previous results. A mean distance of$6.37^{+0.87}_{-0.77}$kpc has been estimated for the bulge sample, based on the observedKmagnitude of the horizontal branch red clump. The metallicity [M/H] distribution was also obtained for a subsample of 60 bulge giants stars, based on calibrated photometric indices. The observed [M/H] shows a peak value at [M/H] ~ −0.1 with an extended metal poor tail and around 30% of the stars with supersolar metallicity. No change in proper motion dispersion was observed as a function of [M/H]. We are currently in the process of obtaining CCDUBV RIphotometry for the entire proper-motion sample of ~ 21,000 stars.

scholarly journals Using ground based data as a precursor for Gaia in getting proper motions of satellites

2017 ◽  
Vol 12 (S330) ◽  
pp. 210-213
Author(s):  
Tobias K. Fritz ◽  
Sean T. Linden ◽  
Paul Zivick ◽  
Nitya Kallivayalil ◽  
Jo Bovy
Keyword(s):  
Adaptive Optics ◽  
Globular Cluster ◽  
Proper Motion ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Optical Data ◽  
Line Of Sight ◽  
Wide Field ◽  
Proper Motions ◽  
Tidal Stream

AbstractWe present our effort to measure the proper motions of satellites in the halo of the Milky Way with mainly ground based telescopes as a precursor on what is possible with Gaia. For our first study, we used wide field optical data from the LBT combined with a first epoch of SDSS observations, on the globular cluster Palomar 5 (Pal 5). Since Pal 5 is associated with a tidal stream it is very useful to constrain the shape of the potential of the Milky Way. The motion and other properties of the Pal 5 system constrain the inner halo of the Milky Way to be rather spherical. Further, we combined adaptive optics and HST to get an absolute proper motion of the globular cluster Pyxis. Using the proper motion and the line-of-sight velocity we find that the orbit of Pyxis is rather eccentric with its apocenter at more than 100 kpc and its pericenter at about 30 kpc. The dynamics excludes an association with the ATLAS stream, the Magellanic clouds, and all satellites of the Milky Way at least down to the mass of Leo II. However, the properties of Pyxis, like metallicity and age, point to an origin from a dwarf of at least the mass of Leo II. We therefore propose that Pyxis originated from an unknown relatively massive dwarf galaxy, which is likely today fully disrupted. Assuming that Pyxis is bound to the Milky Way we derive a 68% lower limit on the mass of the Milky Way of 9.5 × 1011 M⊙.

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