Tautenburg Schmidt Plates Research Articles

A systematic search for novae in M 31 on a large set of digitized archival Schmidt plates

This paper reports on the detection of optical novae in our neighbour galaxy M31 based on digitized historical Tautenburg Schmidt plates. The accurate positions of the detected novae lead to a much larger database when searching for recurrent novae in M31. We conducted a systematic search for novae on 306 digitized Tautenburg Schmidt plates covering a time span of 36 years from 1960 to 1996. From the database of both ~ 300 000 light curves and about one million detections on only one plate per colour band, nova candidates were efficiently selected by automated algorithms and subsequently individually inspected by eye. We report the detection of 84 nova candidates. We found 55 nova candidates from the automated analysis of the light curves. Among these, 22 were previously unknown, 12 were known but not identified on Tautenburg Schmidt plates before, and 21 novae had been previously discovered on Tautenburg plates. An additional 29 known novae could be confirmed by the detailed investigation of single detections. One of our newly discovered nova candidates shows a high position coincidence with a nova detected about 30 years earlier. Therefore, this object is likely to be a recurrent nova. Furthermore, we re-investigated all 41 nova candidates previously found on Tautenburg plates and confirm all but two. Positions are given for all nova candidates with a typical accuracy of ~ 0.4 arcsec. We present light curves and finding charts as online material. The analysis of the plates has shown the wealth of information still buried in old plate archives. Extrapolating from this survey, digitization of other historical M31 plate archives (e.g. from the Mount Wilson or Asiago observatories) for a systematic nova search looks very promising.

A QSO survey via optical variability and zero proper motion in the M 92 field

The combination of variability and proper motion constraints (VPM search) is believed to provide an unconventional yet efficient search strategy for QSOs with selection effects quite different from conventional optical QSO surveys. Previous studies in a field of high galactic latitude have shown that the VPM method is indeed an efficient search strategy. In the present paper, we describe a further variability-proper motion (VPM) QSO survey on Tautenburg Schmidt plates. The survey is based on an exceptionally large number of 162 B plates centred on M 92 with a time-baseline of more than three decades. Further U and V plates are used to measure time-averaged colour indices, and morphology is evaluated on a deep R plate. Proper motions with Hipparcos -like accuracies as well as variability indices are derived for about 35 000 star-like objects down to . With regard to both the number of plates and the number of objects to be investigated, this is the largest VPM survey performed so far. The present paper is focused on the description of the observational material, the data reduction, the definition of the selection parameters, and the construction of the QSO candidate sample. Furthermore, the selection effects of the VPM-method are discussed a priori. For the present survey, the selection effects are shown to be dominated by the magnitude-dependence of the photometric accuracy. Down to the limiting magnitude of the survey , we identify 62 high-priority QSO candidates and a further 57 candidates of medium priority. Spectroscopic follow-up observations have been performed for all these candidates as well as for additional selected candidates of lower priority; the confirmed QSOs will be presented and discussed in a forthcoming paper.

Schmidt survey in the Galactic anticentre direction. 1. Investigation of open clusters

AbstractA study of four open clusters in the direction of the Galactic anticentre (l = 186°, b = +2°) is presented. In a field of 8.32 square degrees proper motions and B magnitudes for about 79 000 stars down to 19.5 were determined on Tautenburg Schmidt plates. For more than 15 500 of them U magnitudes down to 17.3 could be obtained. Additionally, OCA Schmidt plates were used to determine V, R magnitudes in a larger field of 24.45 square degrees for 271 000 stars down to V = 18.2. For stars brighter than V = 15.5 an accuracy of about 1.5 mas/yr has been estimated for proper motions. The rms errors of stellar magnitudes and colour indices are 0.09 – 0.12 mag.Several open clusters have been already known in this direction of the sky, e.g. NGC 2168 or M 35 (C 0605+243), NGC 2158 (C 0604+241) and IC 2157 (C 0601+240). Inspecting the plates and analysing the colour‐magnitude diagrams and published data, we could identify an additional anonymous cluster C 0605+242 with a projection on the sky near the centre of M 35 but at a larger distance from the Sun.The cluster membership determination was carried out using information on spatial and proper motion distributions of stars in the field. The colour‐magnitude diagrams were derived down to the limiting stellar magnitude. For each cluster the interstellar extinction Av, the diameters of the core and corona, the ages and spatial velocity components (V,W) relative to the LSR in the Y,Z – Galactic directions were determined.The distances to the clusters of 960 pc, 2 600 pc, 2 520 pc and 3 700 pc were obtained for M 35, IC 2157, C 0605+242 and NGC 2158. They show the loci of the clusters in the Local and Perseus spiral arms and at external border of Perseus arm, respectively.

Schmidt plate survey towards the Galactic centre. 2. Stellar statistics in the direction of the Sagittarius‐Carina arm

AbstractA study of the structure and kinematics of the Galaxy from Tautenburg Schmidt plates taken towards the Galactic centre (l = 17.0°, b = +0.8°) is presented. Proper motions and B, V magnitudes were determined for about 36 500 stars up to the limiting magnitude V = 16m.8 in a field of 8.95 square degrees. Proper motion accuracy of about 3 mas/year has been obtained for stars brighter than V = 15m. The rms errors of stellar magnitudes and (B–V) colours is about 0.1 mag.The majority of field stars in the survey are main sequence stars and red giants of the disk. They belong to the Local or Sagittarius‐Carina arms, or they are located between these spiral arms. Comparing the modelled and observed distributions of magnitudes and colours, we specified the interstellar extinction determined in the preceding study of open clusters in this field.The luminosity function towards the Galactic centre was determined for stars with absolute magnitudes from ‐4m.35 to +9m. Kinematical and spatial distribution parameters up to 4 kpc from the Sun were obtained as a function of galactocentric distance.

Beobachtungen Kleiner Planeten. XV.

AbstractA summary is given about the Minor Planet survey performed in 1994 on Tautenburg Schmidt plates. 321 asteroids were observed and 1171 positions are calculated for them. These are 200 asteroids with provisional designations (102 of them have new designations) and 121 numbered objects. Tautenburg observations could give a tribute to 73 planets numbered in the period of this report. Fourteen Tautenburg asteroids have been numbered.

A Study of the Variability and Proper Motions of Quasars based on Tautenburg Schmidt Plates

AbstractWe report on the present status of an ongoing study of variability and proper motion of quasars based on Tautenburg Schmidt plates of the field around M3. The main aspects are: (i) a thorough investigation of variability of a sample of known quasars based on a large number of B plates with a long time baseline and the comparison of variability in U, B, and V; (ii) the variability - proper motion diagram for the objects with B ≲ 20.5 mag in this field and the loci of known quasars in this diagram. The primary aim of this work is to check the suitability of Tautenburg Schmidt plates for a combined variability - proper motion quasar survey.

Beobachtungen Kleiner Planeten. XIV

AbstractA summary is given about the Minor Planet survey performed in 1993 on Tautenburg Schmidt plates. 392 asteroids were observed and 1462 positions are calculated for them. These are 297 asteroids with provisional designations (217 of them have new designations) and 95 numbered objects. Ten new designations originate from the KSO‐ARI‐Survey IV. Tautenburg observations could give a tribute to 50 planets numbered in the period of this report. Six Tautenburg asteroids have been numbered (Tab. 3).

Schmidt plate survey in the galactic centre direction. 1. Investigation of open clusters in the Sagittarius‐Carina spiral arm

AbstractA study of four open clusters on Tautenburg Schmidt plates in the direction to the Galactic Centre (l = 17.0°, b = +0.8°) is presented. In a field of 8.95 square degrees proper motions and B, V magnitudes were determined for about 36 500 stars up to the limiting magnitudes B = 17m.9, V = 16m.8. For stars brighter than B = 16m an accuracy of about 3 mas/year has been estimated for proper motions. The rms errors of stellar magnitudes and (B—V) colours is about 0.1 mag.There are two open clusters already known in this sky area: Trumpler 32 (C 1814‐133) and NGC 6611 (C 1816‐138). By the inspection of the plates two additional anonymous clusters were identified near the double star ADS 11285 or BD −14°5014 (C 1819‐146) and near the star BD −14°5016 (C 1820‐146). The cluster membership determination was carried out using information on spatial and proper motion distributions of stars in the field. The colour‐magnitude diagrams up to the limiting stellar magnitude were constructed. For each cluster interstellar extinction AV, diameters of the core and corona, ages and spatial velocity components (V, W) relative to the LSR in the Y, Z‐galactic directions were derived.The distances to the clusters were obtained to 1720 pc, 2260 pc, 2130 pc and 2130 pc for Trumpler 32, NGC 6611, C 1819‐146 and C 1820‐146, respectively. All clusters are situated in the Sagittarius‐Carina spiral arm. Their spatial location confirms the assumption that galactic spiral arms are close to logarithmic spirals with a characteristic angle of about 20 degrees.

Kinematics of Galactic Globular Clusters from Schmidt-Plate Astrometry

From measurements of Tautenburg Schmidt plates with the APM facility in Cambridge we obtained absolute proper motions of the Galactic globular clusters M 3 and M 92 directly with respect to large numbers of background galaxies (Scholz et al. 1993, 1994). We have extended our work to the dSphs in Draco and Ursa Minor (Scholz & Irwin 1994) and to other Galactic globular clusters using Tautenburg, Palomar and UK Schmidt plates. Combining our absolute proper motion of a cluster with its known radial velocity and distance (using common parameters of the solar motion) we derive the cluster orbit in the Galaxy (cf. Odenkirchen & Brosche 1992).

Absolute proper motion and Galactic orbit of M92

In a continuation of our programme to investigate the proper motion of Galactic halo globular clusters, we have used the APM facility to determine directly the tangential motion of the globular cluster M92 with respect to a well-defined extragalactic reference frame. Five pairs of Tautenburg Schmidt plates centred on the cluster, with epoch differences from 23 to 27 yr, were measured. In the independent proper motion determination with 1500 to 2300 reference galaxies for each pair of plates we used third-order polynomials and a stepwise regression method. The mean absolute proper motion of the cluster is found to be μ x =−0.44±0.07, μ y =+0.11±0.04 arcsec (100 yr) −1

Absolute Proper Motions of the Dwarf Spheroidal Galaxies in Draco and Ursa Minor

Palomar and Tautenburg Schmidt plates with a base line of about 35 years have been measured with the Automated Photographic Measuring (APM) system in Cambridge (UK) in order to obtain the proper motions of the Galactic dwarf spheroidal satellites (dSph) in Draco and Ursa Minor with respect to a well defined extragalactic reference frame. The investigations were encouraged by the accuracy level achieved for the mean absolute proper motions of galactic globular clusters (0.05 arcsec/century from 25 years base line Tautenburg plate pairs) which is comparable to the expected proper motion of the Draco and Ursa Minor dSph assuming tangential motions of about 100 km/s. Different methods for the removal of systematic errors in the absolute proper motion introduced by the measuring and reduction process are discussed. The more accurate relative proper motions of individual stars in both dSphs obtained by Stetson (1980) and by Cudworth, Olszewski & Schommer (1986) provide an external comparison and are also used to obtain the mean absolute proper motion of the dSphs.

Membership of faint stars in the globular cluster M3

AbstractA proper motion study from Tautenburg Schmidt plates is presented for the globular cluster M3 and its vicinity. The plates were scanned with the Automated Photographic Measuring (APM) system in Cambridge (UK). A photographic B,V photometry and star counts on the deepest plates were carried out. With a limiting magnitude of about B = 21.4 proper motions with an accuracy from 2 to 3 mas/yr have been obtained for stars with B 19. The proper motions were determined using a stepwise regression method with 3rd order polynomials in the plate‐to‐plate solutions with about 2000 reference galaxies. The results which were corrected for systematic errors dependent on position and magnitude of the stars were used for the determination of membership probabilities. We also looked for possible internal motions of M3.

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

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.

Orbits of Galactic Globular Clusters from Schmidt Plate Astrometry

We present results from orbit integrations for the globular clusters M 3 and M 92. Absolute proper motions recently measured from Tautenburg Schmidt plates and a three-component mass model for the Galaxy have been used to derive the galactic orbits of these clusters. Orbital parameters and the influence of observational uncertainties on the determination of the orbits are discussed.

Photographic photometry for stellar statistics with Tautenburg Schmidt telescope

AbstractPhotometric properties of deep Tautenburg Schmidt plates in the UBV system over the whole field and over a wide range of stellar magnitudes are discussed. Different reduction models based on the calibration curve alone and with additional terms containing colour and plate coordinates are considered.With the filter‐emulsion combinations used the Johnson UBV system can be reproduced quite well by the Tautenburg telescope. The accuracy of photometric data can be improved if geometrical terms are taken into account. For deep plates with a significant effect of background nebulosity a supplementary term is to be included in the reduction model. The polynomial coefficients vary in dependence on spectral bands and individual properties of each plate.

Investigation of the kinematics and structure of the Galaxy in the vicinity of the North galactic pole

AbstractIn the framework of the programme of studying the meridional section of the Galaxy (MEGA) the absolute proper motions of more than 11000 stars with respect to 3000 galaxies and their stellar magnitudes in the B, V Johnson system are determined in two sky regions near the North Galactic Pole (NGP) by means of Tautenburg Schmidt plates. The limiting and completing apparent stellar magnitudes are B = 20.4 and 18.3 mag, the overall and the investigated sky areas are 16.4 and 14.6 square degrees, respectively. Distances have been determined using the stellar magnitudes, colours, proper motions and reduced proper motions. Stellar kinematics, eccentricities of Galactic orbits, spatial distribution and changes of these characteristics with Z‐distance from the Galactic plane are obtained up to 15 kpc. Four subsystems distinguished in the NGP direction, respectively with semithicknesses of 0.25, 0.38, 0.67, 1.48 kpc and density ellipsoid axial ratios of 0.09, 0.20, 0.28, 0.49 show mean velocities in the Galactic rotation direction relative to the LSR of 5.6 ± 0.6, − 11.0 ± 0.6, − 62.5 ± 1.2, − 181.6 ± 4.4 km/s, and ages of 0.1, 0.4, 0.9, 1 of the Galaxy age.

The absolute proper motion and Galactic orbit of M3

The combination of Schmidt plates and an automatic measuring machine provides a powerful method for investigating the proper motions of both the Galactic halo globular clusters and the nearby Galactic dwarf spheroidal satellites. We describe the first direct measurement of the absolute proper motion of a Galactic globular cluster with respect to a large number of background galaxies. Five pairs of Tautenburg Schmidt plates centred on the cluster M3, with epoch differences from 20 to 23 yr, were scanned using the automatic plate measuring facility in Cambridge. The proper motion determination was based on a stepwise regression method with generalized third-order polynomials and used between 1200 and 2200 galaxies for each pair of plates to define an inertial reference frame. The mean absolute proper motion of the cluster is found to be |${\mu}_{x} = -0.31 \pm 0.02\enspace \text {and}\enspace {\mu}_{y} = -0.23 \pm 0.04\enspace \text {arcsec}\, ({100\, \text {yr}})^{-1}$|⁠. Using this proper motion, together with the known radial velocity and distance to M3, we can infer the orbital parameters of the globular cluster in a Galactocentric inertial system.

Absolute Proper Motion of Galactic Globular Clusters

Using automated scans of Tautenburg Schmidt plates with the APM facility in Cambridge (UK) the mean tangential motion of two globular clusters, M3 and M92, is determined directly with respect to a well defined extragalactic reference frame. In both fields five pairs of plates centred on the cluster with epoch differences from 20 to 27 years were measured. In the independent proper motion determination with 1200 to 2300 reference galaxies for each pair of plates we used 3rd order polynomials and a stepwise regression method. The mean absolute cluster p.m. corrected for systematic effects dependent on the coordinates was obtained with an accuracy of ±0.03 arcsec/century for M3 and ±0.06 arcsec/century for M92.

Density profiles and luminosity functions of the globular clusters M3 and M92

Tautenburg Schmidt plates with the globular clusters M3 and M92 were measured on the APM facility in Cambridge, mainly for astrometric purposes. The data were used to derive the radial density profiles and the luminosity functions of these clusters. There is a good agreement of our results with formerly ones derived by other authors. In both clusters effects of mass segregation are observed.

Image detection and separation on Tautenburg Schmidt plates with the ASAG program package

AbstractThe Babelsberg image processing system which will be used for the new automated measuring machine ASAG (Astronomisches Auswertegerät) includes as special feature an adaptive filtering technique. This technique allows a reduction of noise and the determination of the background in astronomical pictures and has already been used for the surface photometry of galaxies on Schmidt plates. For astrometric purposes a method of detecting and separating images in two‐dimensional measuring rasters was developed within the frame of the ASAG software and algorithms.