Automated Identification of Unresolved Binaries using Medium Band Photometry (2005)
Willemsen, P. G., Kaempf, T. A., De Boer, K. S.
We have simulated Gaia medium band photometry in the 1X system for (synthetic) binaries and single stars for G = 15 to 20 mag end-of-mission as well as single shot photometry. Each binary is a system...
Kinematics of RHB stars to trace the structure of the galaxy (2004)
Kaempf, T. A., De Boer, K. S., Altmann, M.
Red horizontal-branch (RHB) stars have been selected from the HIPPARCOS catalogue to investigate their kinematics and spatial distribution. HIPPARCOS parallaxes, literature radial velocities and...
Intermediate scale structure of the interstellar medium towards NGC 6231 in Sco OB1 with FUSE (2003)
Marggraf, O., Bluhm, H., De Boer, K. S.
The FUSE far-ultraviolet interstellar spectra toward seven targets in NGC 6231 show that the molecules H_2, HD, and CO as well as various atomic species are distributed in several clouds. The main...
Studying the populations of our Galaxy using the kinematics of sdB stars (2003)
Altmann, M., Edelmann, H., De Boer, K. S.
We have analysed the kinematics of a sample of 114 hot subdwarf stars, for 2/3 of which we present new proper motions, spectroscopic and photometric data. The vast majority of the stars show a...
Spectrophotometric information from the DIVA satellite (2003)
De Boer, K. S., Willemsen, P. G., Reif, K., Poschmann, H., Kaempf, T. A., ...
The DIVA satellite will, in addition to the astrometry, obtain photometric data for about 40 million survey stars and spectral data for about a third of these. Relevant sections of the CCD-data...
Automated determination of stellar parameters from simulated dispersed images for DIVA (2003)
Willemsen, P. G., Kaempf, T. A., De Boer, K. S.
We have assessed how well stellar parameters (Teff, log g and [M/H]) can be retrieved from low-resolution dispersed images to be obtained by the DIVA satellite. Although DIVA is primarily an all-sky...
Kahabka, P., De Boer, K. S., Bruens, C.
We use 50 (candidate) background X-ray sources (AGN) in the LMC field observed in ROSAT PSPC observations to derive the observed log N - log S relation. We correct for the varying PSPC exposure and...
Sagar, R, Munari, U, De Boer, K. S
We derive cluster parameters and mass functions from new UBVRI CCD photometric observations of ~3500 stars reaching down to V~20mag for the distant southern open star clusters NGC 3105, NGC 3603,...
Kahabka, P., De Boer, K. S., Bruens, C.
We analyzed a sample of 26 background X-ray sources in a ~60 square degree field of the Large Magellanic Cloud observed with the ROSAT PSPC. The sample has been selected from previously classified...
HI spectra and column densities toward HVC and IVC probes (2001)
Wakker, B. P., Kalberla, P. M. W., Van Woerden, H., De Boer, K. S., Putman, M. E.
We show 21-cm line profiles in the direction of stars and extragalactic objects, lying projected on high- and intermediate-velocity clouds (HVCs and IVCs). About half of these are from new data...
GAIA: Composition, Formation and Evolution of the Galaxy (2001)
Perryman, M. A. C., De Boer, K. S., Gilmore, G., Høg, E., Lattanzi, M. G., Lindegren, L., ...
The GAIA astrometric mission has recently been approved as one of the next two `cornerstones' of ESA's science programme, with a launch date target of not later than mid-2012. GAIA will provide...
Stellar Associations and their Field East of LMC 4 in the Large Magellanic Cloud (2001)
Gouliermis, D., De Boer, K. S., Keller, S. C., Kontizas, M., Kontizas, E.
We report about the stellar content and the luminosity and mass functions of three stellar associations and their field located on the north-east edge of the super-bubble LMC 4 in the Large...
GAIA: Composition, formation and evolution of the Galaxy (2001)
Perryman, M. A. C., De Boer, K. S., Gilmore, G., Høg, E., Lattanzi, M. G., Lindegren, L., ...
The GAIA astrometric mission has recently been approved as one of thenext two ``cornerstones'' of ESA's science programme, with a launch datetarget of not later than mid-2012. GAIA will provide...
ORFEUS II Echelle spectra: Molecular hydrogen at high velocities toward HD 93521 (2000)
Gringel, W., Barnstedt, J., De Boer, K. S., Grewing, M., Kappelmann, N., Richter, P.
Absorption lines of interstellar molecular hydrogen in the far ultraviolet (FUV) have been observed in the spectrum of the O9.5 halo star HD 93521, located some 1500 pc from the Galactic plane....
Discovery of molecular hydrogen in a high-velocity cloud of the Galactic halo (1999)
Richter, P., De Boer, K. S., Widmann, H., Kappelmann, N., Gringel, W., Grewing, M., ...
We report the discovery of molecular hydrogen absorption in a Galactic high-velocity cloud (HVC) in the direction of the Large Magellanic Cloud. For the same HVC we derive an iron abundance which is...
ORFEUS II echelle spectra: On the H_2/CO ratio in the LMC towards LH 10 (1999)
Richter, P., De Boer, K. S., Bomans, D. J., Heithausen, A., Koornneef, J.
ORFEUS far UV echelle spectra have been used to investigate HI, H_2 and CO absorption lines along the line of sight towards LH 10:3120 in the LMC, extending the study presented by de Boer et al....
BUSCA: A Telescope Instrumentation for Simultaneous Imaging in 4 Optical Bands (1999)
Reif, K., Bagschik, K., De Boer, K. S., Schmoll, J., Mueller, Ph., Poschmann, H, ...
The "Bonn University Simultaneous CAmera" (BUSCA) is a CCD camera system which allows simultaneous direct imaging of the same sky area in four colors. The optics are designed for an f/8 beam and four...
ORFEUS II echelle spectra: Absorption by H_2 in the LMC (1998)
De Boer, K. S., Richter, P., Bomans, D. J., Heithausen, A., Koornneef, J.
We present the first detection of molecular hydrogen (H_2) UV absorption profiles on the line of sight to the LMC. The star LH 10:3120 in the LMC was measured with the ORFEUS telescope and the...
ORFEUS II echelle spectra: The scale height of interstellar O VI in the halo (1998)
Widmann, H., De Boer, K. S., Richter, P., Kraemer, G., Appenzeller, I., Barnstedt, J., ...
FUV high resolution spectra of 18 stars, particularly chosen to observe the interstellar medium (ISM), were obtained during the second ORFEUS-SPAS free flight space shuttle mission in December 1996....
ORFEUS II echelle spectra: Detection of H_2 absorption in SMC gas (1998)
Richter, P., Widmann, H., De Boer, K. S., Appenzeller, I., Barnstedt, J., Goelz, M., ...
We present a study of molecular hyrogen (H_2) in the SMC gas, based on space shuttle Far UV spectroscopy with ORFEUS and the Tuebingen echelle spectrograph, in the line of sight to the SMC star HD...
Hot subdwarf stars - galactic orbits and distribution perpendicular to the plane (1997)
De Boer, K. S., Sanchez, Y. Aguilar, Altmann, M., Geffert, M., Odenkirchen, M., Schmidt, J. H. K., ...
The spatial distribution and the population nature of subdwarf B type stars in the galaxy is investigated based on the kinematics of these stars. The orbits of 41 stars have been calculated using a...
CIV absorption from hot gas inside supergiant shell LMC4 observed with HST and IUE (1996)
Bomans, D. J., De Boer, K. S., Koornneef, J., Grebel, E. K.
High resolution ultraviolet spectra with HST-GHRS of two stars in the direction of the supergiant shell LMC4 unambiguously show absorption by substantial quantities of CIV gas at velocities near the...
King, D. L., Vladilo, G., Lipman, K., De Boer, K. S., Centurion, M, Moritz, P., ...
We present spectroscopic observations of supernova 1994D in NGC 4526, an S0$_3$ galaxy in the Virgo cluster 15 Mpc distant. The datasets consist of the interstellar Ca\II\ and Na\I\ lines towards the...