scholarly journals The Lick Northern Proper Motion Program

1995 ◽  
Vol 166 ◽  
pp. 45-48 ◽  
Author(s):  
A.R. Klemola ◽  
R.B. Hanson ◽  
B.F. Jones
Keyword(s):  
Proper Motion ◽  
Milky Way ◽  
Proper Motions ◽  
Photographic Photometry

The Lick Northern Proper Motion (NPM) Program will provide absolute proper motions (referred to faint galaxies), equatorial coordinates, and two-color photographic photometry for some 300,000 stars with 8 < B < 18 covering the 70% of the sky north of declination −23°. Part 1 of the NPM program (NPM1), recently completed, covers the 72% of the northern sky (899 of 1,246 fields) outside the Milky Way. Two catalogs result from NPM1: The NPM1 Catalog (Klemola et al. 1993a, Hanson 1993a) contains 149,000 stars. The NPM1 Reference Galaxy List (Klemola et al. 1993b, Hanson 1993b) contains 50,000 faint galaxies. Klemola et al. (1987, 1994, 1995) describe the NPM program. Hanson et al. (1994) describe the NPM1 Catalogs.

scholarly journals Proper Motions With Respect to the Extragalactic Reference Frame

1990 ◽  
Vol 141 ◽  
pp. 407-417
Author(s):  
A. R. Klemola
Keyword(s):  
Reference Frame ◽  
Proper Motion ◽  
Milky Way ◽  
Proper Motions ◽  
Stellar Proper Motions

The Lick proper motion program, one of several using galaxies as a reference frame, is summarized with a statement of work accomplished for the non-Milky Way sky. The problem of identifying relatively transparent regions at low galactic latitudes is discussed, with tabular results presented for 41 windows from the literature having observable galaxies. These fields may be helpful for attaching stellar proper motions directly to the extragalactic frame.

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⊙.

scholarly journals The Tautenburg Schmidt Telescope and Galactic Proper Motion Studies

1995 ◽  
Vol 148 ◽  
pp. 267-270 ◽  
Author(s):  
E. Schilbach ◽  
R.-D. Scholz ◽  
S. Hirte
Keyword(s):  
Proper Motion ◽  
Galactic Plane ◽  
Proper Motions ◽  
Schmidt Telescope ◽  
Automatic Measuring ◽  
Wide Range ◽  
Motion Studies ◽  
Photographic Photometry ◽  
Better Than

AbstractThe combination of Tautenburg plates and automatic measuring machines provides a powerful tool to obtain photometry and proper motions of a great number of stars for statistical investigations of our Galaxy. Photographic photometry with an accuracy of about 0.07 mag can be obtained provided two plates of the same colour and a sufficient number of photometric standards are available. With two plate pairs and a 20 years baseline, a proper motion accuracy better than 4 mas/year can be achieved for stars over a wide range of magnitudes. Outside the Galactic plane proper motions are determined with respect to hundreds of background galaxies.

scholarly journals The VMC survey

2020 ◽  
Vol 641 ◽  
pp. A134
Author(s):  
Thomas Schmidt ◽  
Maria-Rosa L. Cioni ◽  
Florian Niederhofer ◽  
Kenji Bekki ◽  
Cameron P. M. Bell ◽  
...  
Keyword(s):  
Proper Motion ◽  
Milky Way ◽  
Dwarf Galaxies ◽  
Dynamical Evolution ◽  
Large Magellanic Cloud ◽  
Small Population ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Proper Motions ◽  
Flow Motion

Context. The Magellanic Clouds are a nearby pair of interacting dwarf galaxies and satellites of the Milky Way. Studying their kinematic properties is essential to understanding their origin and dynamical evolution. They have prominent tidal features and the kinematics of these features can give hints about the formation of tidal dwarfs, galaxy merging and the stripping of gas. In addition they are an example of dwarf galaxies that are in the process of merging with a massive galaxy. Aims. The goal of this study is to investigate the kinematics of the Magellanic Bridge, a tidal feature connecting the Magellanic Clouds, using stellar proper motions to understand their most recent interaction. Methods. We calculated proper motions based on multi-epoch Ks-band aperture photometry, which were obtained with the Visible and Infrared Survey Telescope for Astronomy (VISTA), spanning a time of 1−3 yr, and we compared them with Gaia Data Release 2 (DR2) proper motions. We tested two methods for removing Milky Way foreground stars using Gaia DR2 parallaxes in combination with VISTA photometry or using distances based on Bayesian inference. Results. We obtained proper motions for a total of 576 411 unique sources over an area of 23 deg2 covering the Magellanic Bridge including mainly Milky Way foreground stars, background galaxies, and a small population of possible Magellanic Bridge stars (< 15 000), which mostly consist of giant stars with 11.0 <  Ks <  19.5 mag. The first proper motion measurement of the Magellanic Bridge centre is 1.80 ± 0.25 mas yr−1 in right ascension and −0.72 ± 0.13 mas yr−1 in declination. The proper motion measurements of stars along the Magellanic Bridge from the VISTA survey of the Magellanic Cloud system (VMC) and Gaia DR2 data confirm a flow motion from the Small to the Large Magellanic Cloud. This flow can now be measured all across the entire length of the Magellanic Bridge. Conclusions. Our measurements indicate that the Magellanic Bridge is stretching. By converting the proper motions to tangential velocities, we obtain ∼110 km s−1 in the plane of the sky. Therefore it would take a star roughly 177 Myr to cross the Magellanic Bridge.

scholarly journals Microarcsecond astrometry in the Local Group

2007 ◽  
Vol 3 (S248) ◽  
pp. 474-480
Author(s):  
A. Brunthaler ◽  
M. J. Reid ◽  
H. Falcke ◽  
C. Henkel ◽  
K. M. Menten
Keyword(s):  
Proper Motion ◽  
Milky Way ◽  
Local Group ◽  
Statistical Error ◽  
Dark Matter Halo ◽  
Proper Motions ◽  
Angular Rotation ◽  
Vlbi Observations ◽  
Ic 10 ◽  
Motion Measurements

AbstractMeasuring the proper motions and geometric distances of galaxies within the Local Group is very important for our understanding of its history, present state and future. Currently, proper motion measurements using optical methods are limited only to the closest companions of the Milky Way. However, given that VLBI provides the best angular resolution in astronomy and phase-referencing techniques yield astrometric accuracies of ≈ 10 micro-arcseconds, measurements of proper motions and angular rotation rates of galaxies out to a distance of ~ 1 Mpc are feasible. This paper presents results of VLBI observations in regions of H2O maser activity of the Local Group galaxies M33 and IC 10. Two masing regions in M33 are on opposite sides of the galaxy. This allows a comparison of the angular rotation rate (as measured by the VLBI observations) with the known inclination and rotation speed of the Hi gas disk leading to a determination of a geometric distance of 730 ± 100 ± 135 kpc. The first error indicates the statistical error of the proper-motion measurements, while the second error is the systematic error of the rotation model. Within the errors, this distance is consistent with the most recent Cepheid distance to M33. Since all position measurements were made relative to an extragalactic background source, the proper motion of M33 has also been measured. This provides a three dimensional velocity vector of M33, showing that this galaxy is moving with a velocity of 190 ± 59 km s−1 relative to the Milky Way. For IC 10, we obtain a motion of 215 ± 42 km s−1 relative to the Milky Way. These measurements promise a new handle on dynamical models for the Local Group and the mass and dark matter halo of Andromeda and the Milky Way.

scholarly journals A New Absolute Proper Motion Determination of Leo I Using HST/WFPC2 Images and Gaia EDR3

2021 ◽  
Vol 163 (1) ◽  
pp. 1
Author(s):  
Dana I. Casetti-Dinescu ◽  
Caitlin K. Hansen ◽  
Terrence M. Girard ◽  
Vera Kozhurina-Platais ◽  
Imants Platais ◽  
...  
Keyword(s):  
Proper Motion ◽  
Milky Way ◽  
Proper Motions ◽  
Large Area ◽  
Field Of Study ◽  
Data Set ◽  
Polar Structure ◽  
The Galaxy ◽  
The Absolute

Abstract We measure the absolute proper motion of Leo I using a WFPC2/HST data set that spans up to 10 yr to date the longest time baseline utilized for this satellite. The measurement relies on ∼2300 Leo I stars located near the center of light of the galaxy; the correction to absolute proper motion is based on 174 Gaia EDR3 stars and 10 galaxies. Having generated highly precise, relative proper motions for all Gaia EDR3 stars in our WFPC2 field of study, our correction to the absolute EDR3 system does not rely on these Gaia stars being Leo I members. This new determination also benefits from a recently improved astrometric calibration of WFPC2. The resulting proper-motion value, (μ α , μ δ ) = (−0.007 ± 0.035, − 0.119 ± 0.026) mas yr−1 is in agreement with recent, large-area, Gaia EDR3-based determinations. We discuss all the recent measurements of Leo I’s proper motion and adopt a combined, multistudy average of ( μ α 3 meas , μ δ 3 meas ) = ( − 0.036 ± 0.016 , − 0.130 ± 0.010 ) mas yr−1. This value of absolute proper motion for Leo I indicates its orbital pole is well aligned with that of the vast polar structure, defined by the majority of the brightest dwarf spheroidal satellites of the Milky Way.

scholarly journals Astrometry and Galactic Structure

1994 ◽  
Vol 161 ◽  
pp. 425-434
Author(s):  
S.R. Majewski
Keyword(s):  
Proper Motion ◽  
Globular Clusters ◽  
Milky Way ◽  
Galactic Structure ◽  
Proper Motions ◽  
Future Prospects ◽  
The Status ◽  
Galactic Globular Clusters ◽  
Remarkable Agreement

The application of astrometric surveys to understanding the structure and kinematics of the Milky Way is discussed, with particular emphasis on some of the issues expected to be addressed in the next decade or so. It is shown that the results of complete proper motion surveys of field stars at the Galactic poles are in remarkable agreement concerning the global kinematics of stars as a function of distance, but that significant differences exist in how these data are decomposed to derive the kinematics of individual Galactic components. The status and future prospects regarding the measurement of proper motions and orbits for Galactic globular clusters and satellites are also discussed.

scholarly journals An attempt to Derive the Proper Motion for Blanco Cluster 1

1995 ◽  
Vol 148 ◽  
pp. 232-233
Author(s):  
Bambang Hidayat ◽  
Paulus Wiyanto
Keyword(s):  
Proper Motion ◽  
Milky Way ◽  
High Ratio ◽  
Open Clusters ◽  
Photometric Data ◽  
Point Of View ◽  
Large Field ◽  
Small Field ◽  
Proper Motions ◽  
Field Solution

In order to establish the probability of physical membership of open clusters by means of astrometrical methods, two criteria are used: the position distribution of stars in the sky and their proper motions. Proper motion methods have shown validity from a practical point of view; but are difficult to apply where there is a high ratio of cluster-to-field stars, and in crowded fields of the Milky Way.As a test we have selected the nearby (170–190 pc) Blanco Cluster 1 (1 = 16°, b = −73°) in order to avoid complications arising from crowded fields. Photometric data however, suggests that the diameter of the cluster is rather extended (~ 120 arcsec). This will require a large-field solution, rather than a small-field solution which can be obtained with greater accuracy using Schmidt astrometry (Fresneau 1978; Nakamura & Sekiguchi 1993).

scholarly journals The Milky Way bar/bulge in proper motions: a 3D view from VIRAC and Gaia

2019 ◽  
Vol 489 (3) ◽  
pp. 3519-3538 ◽  
Author(s):  
Jonathan P Clarke ◽  
Christopher Wegg ◽  
Ortwin Gerhard ◽  
Leigh C Smith ◽  
Phil W Lucas ◽  
...  
Keyword(s):  
Proper Motion ◽  
Milky Way ◽  
Selection Function ◽  
Full Potential ◽  
Proper Motions ◽  
Bulge Region ◽  
Similar Distance ◽  
Pattern Speed ◽  
The Mean ◽  
Red Clump

Abstract We have derived absolute proper motions of the entire Galactic bulge region from VVV Infrared Astrometric Catalogue (VIRAC) and Gaia. We present these both as integrated on-sky maps and, after isolating standard candle red clump (RC) stars, as a function of distance using RC magnitude as a proxy. These data provide a new global, 3D view of the Milky Way barred bulge kinematics. We find a gradient in the mean longitudinal proper motion, $\langle \mu _ l^\star \rangle $, between the different sides of the bar, which is sensitive to the bar pattern speed. The split RC has distinct proper motions and is colder than other stars at similar distance. The proper motion correlation map has a quadrupole pattern in all magnitude slices showing no evidence for a separate, more axisymmetric inner bulge component. The line-of-sight integrated kinematic maps show a high central velocity dispersion surrounded by a more asymmetric dispersion profile. $\sigma _{\mu _l} / \sigma _{\mu _b}$ is smallest, ≈1.1, near the minor axis and reaches ≈1.4 near the disc plane. The integrated $\langle \mu_b\rangle$ pattern signals a superposition of bar rotation and internal streaming motion, with the near part shrinking in latitude and the far part expanding. To understand and interpret these remarkable data, we compare to a made-to-measure barred dynamical model, folding in the VIRAC selection function to construct mock maps. We find that our model of the barred bulge, with a pattern speed of 37.5 $\mathrm{ \mathrm{ km \, s^{-1}} \, kpc^{-1} }$, is able to reproduce all observed features impressively well. Dynamical models like this will be key to unlocking the full potential of these data.

scholarly journals Maintenance and densification: current proper-motion catalogs

2007 ◽  
Vol 3 (S248) ◽  
pp. 303-309
Author(s):  
T. M. Girard
Keyword(s):  
Proper Motion ◽  
Reference System ◽  
Milky Way ◽  
Raw Material ◽  
Proper Motions ◽  
Schmidt Telescope ◽  
Large Area ◽  
Milky Way Galaxy ◽  
Celestial Reference System

AbstractAn overview of currently available, large-area, proper-motion catalogs is presented. These include the well-known catalogs based on historical Schmidt-telescope surveys as well as other projects that make use of observational material the primary purpose of which, from inception, was the determination of proper motions. The various catalogs are characterized and compared, with an emphasis on their limitations and their appropriateness for various astrophysical uses.In addition to allowing for the maintenance of a practical celestial reference system, absolute proper-motion surveys provide the raw material from which a better understanding of our Galaxy's structure and kinematics can be built. Several examples will be cited in which large proper-motion surveys are used to probe and describe the distinct stellar components that comprise our Milky Way Galaxy.

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