We present the results of an internal proper motion analysis of the inner region of M15 using Hubble Space Telescope Wide Field Planetary Camera 2 images. The motions of 704 stars with brightnesses above that of the cluster turnoff (V<18.3) are analyzed to determine the velocity dispersion profile within about 15" of the cluster center. The average signal-to-noise ratio of these motions is about 3, and stars in the innermost radial bin have an average core distance of only 0.7". Assuming a distance to M15 of 10kpc, we estimate that the velocity dispersion within this innermost bin is 14.5+/-2.5km/s and that it slowly decreases outward, reaching a value of 9.8+/-0.8km/s at R=15.6". We find that the proper-motion dispersion profile is in good agreement with the predictions of recent N-body simulations that do not require the presence of a central intermediate-mass black hole (IMBH). The agreement between the observed profile and the N-body simulations is marginally improved if one assumes that when a neutron star is created as a result of stellar evolution, it escapes from the cluster. Based on the results of this study and a review of other investigations, it is concluded that there is little direct evidence that M15 possesses an intermediate-mass black hole.
The results of astrometric and photometric investigations of the open cluster NGC 7243 are presented. Proper motions of 2165 stars with root-mean-square error of 1.1mas/yr were obtained by means of PDS scanning of astrometric plates covering the time interval of 97 years. A total of 211 cluster members down to V=15.5mag have been identified. V and B magnitudes have been determined for 2118 and 2110 stars respectively. Estimations of mass 348M_{sun}_<M<522M_{sun}_, age t=2.510^8^yr, distance r=698pc and reddening E(B-V)=0.24 of the cluster NGC 7243 have been made.
We analyze data from the Hubble Space Telescope's (HST) Advanced Camera for Surveys of the globular cluster (GC) Omega Cen. We construct a photometric catalog of 1.2x10^6^ stars over a 10'x10' central field down to below B_F435W_=25 (M~0.35M_{sun}_). The 2.5 to 4 year baseline between observations yields a catalog of some 10^5^ proper motions over a smaller area, with 53382 "high-quality" measurements in a central R<~2' field. Artificial-star tests characterize the photometric incompleteness. We determine the cluster center to ~1" accuracy from star counts using two different methods, one based on isodensity contours and the other on "pie slices." We independently confirm the result by determining also the kinematical center of the HST proper motions, as well as the center of unresolved light seen in Two Micron All Sky Survey data. All results agree to within their 1"-2" levels of uncertainty. The proper-motion dispersion of the cluster increases gradually inward, but there is no variation in kinematics with position within the central ~15": there is no dispersion cusp and no stars with unusually high velocities. We measure for the first time in any GC the variation in internal kinematics along the main sequence.
The tables present the photometric and astrometric results of an extensive proper motion study of the globular cluster omega Centauri: information on the photographic plates used, variability analysis, astrometric data for 9847 stars, membership determination and surface density profile, cluster proper motion dispersions and systematics and cross-references with star-numbers used by Norris et al. (1997ApJ...487L.187N) and Lynga (1996A&AS..115..297L).
Large-scale astrometric and photometric data bases have been used to search for and confirm stellar membership of the open cluster IC 2391. 125 stars were found that satisfied criteria for membership based on proper motion components and BRI photometry from the United States Naval Observatory B (USNO-B, Cat. <I/284>) catalogue and JHK photometry from the Two Micron All Sky Survey (2MASS, Cat. <II/246>) catalogue. This listing was compared with others recently published. A distance to the cluster of 147.7+/-5.5pc was found with mean proper motion components, from the Tycho2 catalogue of (-25.04+/-1.53mas/yr; +23.19+/-1.23mas/yr). A revised Trumpler classification of II3r is suggested. Luminosity and mass functions for the candidate stars were constructed and compared with those of field stars and other clusters.
We present a new, probabilistic method for determining the systemic proper motions of Milky Way (MW) ultra-faint satellites in the Dark Energy Survey (DES). We utilize the superb photometry from the first public data release (DR1) of the DES to select candidate members and cross-match them with the proper motions from the Gaia DR2. We model the candidate members with a mixture model (satellite and MW) in spatial and proper motion space. This method does not require prior knowledge of satellite membership and can successfully determine the tangential motion of 13 DES satellites. With our method, we present measurements of the following satellites: Columba I, Eridanus III, Grus II, Phoenix II, Pictor I, Reticulum III, and Tucana IV. This is the first systemic proper motion measurement for several of these satellites, and the majority lack extensive spectroscopic follow-up studies. We compare these to the predictions of Large Magellanic Cloud satellites and the vast polar structure. With the high-precision DES photometry, we conclude that most of the newly identified member stars are very metal-poor ([Fe/H]<=-2), similar to other ultra-faint dwarf galaxies, while Reticulum III is likely more metal-rich. We also find potential members in the following satellites that might indicate their overall proper motion: Cetus II, Kim 2, and Horologium II. However, due to the small number of members in each satellite, spectroscopic follow-up observations are necessary to determine the systemic proper motion in these satellites.
We present and analyse a catalogue of 233 pulsars with proper motion measurements. The sample contains a wide variety of pulsars including recycled objects and those associated with globular clusters or supernova remnants. After taking the most precise proper motions for those pulsars for which multiple measurements are available, the majority of the proper motions (58 per cent) are derived from pulsar timing methods, 41% using interferometers and the remaining 1% using optical telescopes.
We report new photometry and radial velocities for almost 500 stars from the Lowell Proper Motion Catalog. We combine these results with our prior sample and rederive stellar temperatures based on the photometry, reddening, metallicities (using Chi^2 matching of our 22,500 low S/N high resolution echelle spectra with a grid of synthetic spectra), distances, space motions, and Galactic orbital parameters for 1269 (kinematics) and 1261 (metallicity) of the 1464 stars in the complete survey. The frequency of spectroscopic binaries for the metal-poor ([m/H]<=-1.2) stars with periods shorter than 3000 days is at least 15%. The spectroscopic binary frequency for metal-rich stars ([m/H]>-0.5) appears to be lower, about 9%, but this may be a selection effect. We also discuss special classes of stars, including treatment of the double-lined spectroscopic binaries, and identification of subgiants. Four possible new members of the class of field blue stragglers are noted. We point out the detection of three possible new white dwarfs, six broad-lined (binary) systems, and discuss briefly the three already known nitrogen-rich halo dwarfs.
Proper Motions, UBV Photometry, Four Open Clusters
Short Name:
V/28
Date:
21 Oct 2021
Publisher:
CDS
Description:
Proper motions were determined for 2169 stars with limiting magnitude B = 16.5 mag and located within a 60x60' area centered at RA = 23h54.2min, Dec = 60deg57arcmin (1950.0). Three plate pairs with a mean epoch difference of 49 years were used. The first epoch plates were taken with the Tashkent normal astrograph during 1923-1925 and the second epoch plates with the Pulkovo normal astrograph. The proper motions have a mean error +/-0.0030 arcsec (B < 14.5 mag) and +/-0.0036 arcsec (B > 14.5 mag) and were measured relative to reference stars with 13.5 mag <= B <= 14.5 mag. Photographic UBV magnitudes were measured using Sandages photoelectric standards. The U, B and V magnitudes were determined for 1930, 2165 and 1734 stars respectively, with the corresponding mean errors +/-0.03 mag, +/-0.06 mag and +/-0.05 mag. In the measured area there are three known open clusters (NGC 7788, NGC 7790 and Berkeley 58) and a previously unknown open cluster, discovered by the author, centered at RA =23 h 54.9 min, Dec = 61 deg 21 arcmin (1950.0). The cluster members were selected on the basis of the proper motion (vector diagram) and photometric (V ~ B-V and U-B ~ B-V) criteria. Stars within areas with 4 arcmin radii centered on NGC 7788 and NGC 7790 and 6 arcmin radii centered on Berkeley 58 and the anonymous cluster were investigated for cluster membership. The method of reduction of the observational data and the results obtained have been published in Izv. Pulkovo 195, 80, 1977 and 196, 69, 1979.
Proper Motions, UBV-Phot. & Spectral Class Region 7092
Short Name:
I/203
Date:
21 Oct 2021
Publisher:
CDS
Description:
A catalogue of positions, proper motions and photographic UBV-magnitudes for 7931 stars in and around the open cluster NGC 7092 (M39) is presented. The Catalogue is complete down to B=16.0m and covers an area with diameter of ~110'. The spectral types are provided for 511 stars generally brighter than B=13.0m. For convenience, basic cross-identifications are also included. Refer to the file "intro.txt" for full details about the catalogue.
