Deep CCD Photometry and the Initial Mass Function of the Core of the OB Cluster Berkeley 86

Based on photometry of deep CCD frames of the central region of the OB cluster Berkeley 86, we derive the cluster mass function. The absence of current star formation, and the cluster\u27s young age of about 6Myrs, leads to the conclusion that the initial mass function (IMF) and the current mass function are identical for stars with m\u3c 10msun_. In the range of 1.2-20msun_, an IMF with a slope of {GAMMA}=-1.3+/-0.3 is found. This value agrees well with other recent determinations of young clusters IMFs which are close to the classical Salpeter IMF with {GAMMA}=-1.35. Sections of the IMF of Berkeley 86 that are significantly steeper, or flatter, are most likely the result of a dip in the star\u27s mass distribution in the range of 3.5-10msun_. Similar dips may have led to steep IMFs over narrow mass ranges, as reported in the literature for some other clusters. No sign for a low mass turn-over in the IMF of Berkeley 86 is found for masses extending down to 0.85 msun _ (Refer to PDF file for exact formulas)

Web servis Otvorenoga geoprostornog konzorcija u složenim sustavima distribucije

The short review of the Open Geospatial Consortium (OGC) web service with regard to Web Map Service (WMS) and Web Feature Service (WFS) has been given in this work from the perspective of server and client applications. The problems of the exchange of spatial data in the complex systems as municipal service have been described. Based on analysis of data exchange between employees in the same company and exchange between municipal services the existing condition has been schematically shown. Having this in mind, the proposal of measures has been given to improve communication by implementing distribution OGC web service with assumption that improvement of communication initiates the progress of overall system as well. Suggested solution is based on open source WMS/WFS servers and clients, but with remark that large number of commercial desktop GIS systems has inbuilt support for OGC web service. In the end it has been pointed out to some possible specialized client’s requests in regard to data safety and control of data access, as well as some extended types of data such as topological structures, surfaces and alike. Described model of distribution exchange can be applied to all complex systems, but within smaller systems such as companies which consist of more sectors.Rad prikazuje kratki pregled web servisa Otvorenog geoprostornog konzorcija (OGC) u odnosu na Web Map Service (WMS) i Web Feature Service (WFS) iz perspektive aplikacija servera i korisnika. Opisani su problemi razmjene prostornih podataka u složenom sustavu kao zajedničkom servisu. Na temelju analize razmjene podataka između zaposlenika u istoj tvrtki i razmjene između servisa zajednice shematski je prikazano postojeće stanje. Imajući to na umu dan je prijedlog mjera za poboljšanje komunikacije koristeći raspodjelu OGC web servisa pod pretpostavkom da poboljšanje komunikacije pokreće također i razvitak cjelokupnog sustava. Predloženo rješenje temelji se na serverima i klijentima otvorenog servisa WMS/WFS, uz napomenu da veliki broj komercijalnih desktop GIS sustava ima ugrađenu podršku za OGC web servis. Na kraju je ukazano na neke moguće zahtjeve klijenata u vezi sa sigurnošću podataka i kontrolom pristupa podacima, kao i nekim proširenim tipovima podataka kao što su topografske strukture, površine i slično. Opisani model razmjene može se primijeniti na sve složene sustave, ali unutar manjih sustava kao što su tvrtke koje se sastoje od više sektora

CCD Speckle Observations of Binary Stars from the Southern Hemisphere. III. Differential Photometry

Two hundred seventy-two magnitude difference measures of 135 double star systems are presented. The results are derived from speckle observations using the Bessel V and R passbands and a fast readout CCD camera. Observations were taken at two 60 cm telescopes, namely the Helen Sawyer Hogg Telescope, formerly at Las Campanas, Chile, and the Lowell-Tololo Telescope at the Cerro Tololo Inter- American Observatory, Chile. The data analysis method is presented and, in comparing the results to those of Hipparcos as well as to recent results using adaptive optics, we find very good agreement. Overall, the measurement precision appears to be dependent on seeing and other factors but is generally in the range of 0.10-0.15 mag for single observations under favorable observing conditions. In four cases, multiple observations in both V and R allowed for the derivation of component V-R colors with uncertainties of 0.11 mag or less. Spectral types are assigned and preliminary effective temperatures are estimated in these cases

CCD Speckle Observations of Binary Stars from the Southern Hemisphere. II. Measures from the Lowell-Tololo Telescope During 1999

Speckle observations of 145 double stars and suspected double stars are presented and discussed. On the basis of multiple observations, a total of 280 position angle and separation measures are determined, as well as 23 high-quality nondetections. All observations were taken with the (unintensified) Rochester Institute of Technology fast-readout CCD camera mounted on the Lowell-Tololo 61 cm telescope at the Cerro Tololo Inter-American Observatory during 1999 October. We find that the measures, when judged as a whole against ephemeris positions of binaries with very well-known orbits, have root mean square deviations of (1.8+/- 0.3) degrees in position angle and (13+/-2) mas in separation. Eleven double stars discovered by Hipparcos were also successfully observed, and the change in position angle and/or separation since the Hipparcos observations was substantial in three cases (Refer to PDF file for exact formulas)

CCD Speckle Observations of Binary Stars from the Southern Hemisphere

We present 119 position angle and separation measures of 86 double stars observed by way of speckle interferometry with the University of Toronto Southern Observatory 60 cm telescope at Las Campanas, Chile. Speckle interferograms are recorded with a bare (unintensified) front-illuminated CCD in a fast subarray-readout mode. Position angles and separations are determined by a weighted least-squares fitting algorithm applied to the binary power spectra, and the 180-degree ambiguity in the position angle inherent in this approach is resolved by bispectral analysis. In this configuration the 60 cm telescope exhibits near-diffraction-limited performance. Initial results indicate that our separation measures have a root-mean-square (rms) deviation of 6.6 +/- 1.0 milliarcsecond (mas) and our position angles have an rms deviation of 1.73 +/- 0.26 degrees when judged against the ephemeris positions of a small sample of binaries with previously well-determined orbits (Refer to PDF file for exact formulas)

Imaging of Laser-Plasma X-ray Emission with Charge-Injection Devices

This work details the method of obtaining time-integrated images of laser–plasma x-ray emission using charge-injection devices (CIDs), as has been demonstrated on the University of Rochester’s 60-beam UV OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. The CID has an architecture similar to a charge-coupled device. The differences make them more resistant to radiation damage and, therefore, more appropriate for some application in laser–plasma x-ray imaging. CID-recorded images have been obtained with x-ray pinhole cameras, x-ray microscopes, x-ray spectrometers, and monochromatic x-ray imaging systems. Simultaneous images obtained on these systems with calibrated x-ray film have enabled determination of the absolute detection efficiency of the CIDs in the energy range from 2 to 8 keV