Publications (16)
Proper motions of Local Group dwarf spheroidal galaxies I: First ground-based results for Fornax
René. A. Méndez, Edgardo Costa, Mario H. Pedreros +3
In this paper we present in detail the methodology and the first results of a ground-based program to determine the absolute proper motion of the Fornax dwarf spheroidal galaxy. Th…
On the Origin of Mass Segregation in NGC 3603
Xiaoying Pang, Eva K. Grebel, Richard J. Allison +5
We present deep Hubble Space Telescope/Wide Field and Planetary Camera 2 photometry of the young HD 97950 star cluster in the giant H {\sc ii} region NGC 3603. The data were obtain…
The Evolution of Ly-alpha Emitting Galaxies Between z = 2.1 and z = 3.1
Robin Ciardullo, Caryl Gronwall, Christopher Wolf +11
We describe the results of a new, wide-field survey for z=3.1 Ly-alpha emission-line galaxies (LAEs) in the Extended Chandra Deep Field South (ECDF-S). By using a nearly top-hat 50…
Long-term photometry of the Wolf-Rayet stars WR 137, WR 140, WR 148, and WR 153
Kyril P. Panov, Martin Altmann, Wilhelm Seggewiss
In 1991, a long term UBV-photometry campaign of four Wolf-Rayet stars was started using the 60 cm telescope of the National Astronomical Observatory Rozhen, Bulgaria. Here we repor…
Searching for merger debris in the Galactic halo: Chemodynamical evidence based on local blue HB stars
Martin Altmann, Marcio Catelan, Manuela Zoccali
We report on the discovery of a group of local A-type blue horizontal-branch (HBA) stars moving in a prograde, comet-like orbit with very similar kinematics and abundances. This se…
Hot Stuff for One Year (HSOY) - A 583 million star proper motion catalogue derived from Gaia DR1 and PPMXL
Martin Altmann, Siegfried Roeser, Markus Demleitner +2
Recently, the first installment of data from ESA's Gaia astrometric satellite mission (Gaia-DR1) was released, containing positions of more than 1 billion stars with unprecedented…
Hypervelocity Stars: Young and Heavy or Old and Light?
Uli Heber, Heiko Hirsch, Heinz Edelmann +4
The first three hyper-velocity stars (HVS) unbound to the Galaxy were serendipitously discovered in 2005. The only suggested origin of hyper-velocity stars is the Galactic Centre a…
Photometric and kinematic studies of open star clusters. II. NGC 1960 (M 36) and NGC 2194
Joerg Sanner, Martin Altmann, Jens Brunzendorf +1
We present CCD photometry and proper motion studies of the two open star clusters NGC 1960 (M 36) and NGC 2194. Fitting isochrones to the colour magnitude diagrams, for NGC 1960 we…
Exceptional sequences of 8 line bundles on (P^1)^3
Klaus Altmann, Martin Altmann
We investigate maximal exceptional sequences of line bundles on (P^1)^3, i.e. those consisting of 2^r elements. For r=3 we show that they are always full, meaning that they generat…
Constraints on the origin of the massive, hot, and rapidly rotating magnetic white dwarf RE J 0317-853 from an HST parallax measurement
Baybars Külebi, Stefan Jordan, Edmund Nelan +2
We use the parallax measurements of RE J 0317-853 to determine its mass, radius, and cooling age and thereby constrain its evolutionary origins. We observed RE J 0317-853 with the…
The Rest-frame Ultraviolet Light Profile Shapes of Ly-alpha-Emitting Galaxies at z=3.1
Caryl Gronwall, Nicholas A. Bond, Robin Ciardullo +4
We present a rest-frame ultraviolet morphological analysis of 78 resolved, high S/N z ~ 3.1 Lyman Alpha Emitters (LAEs) in the Extended Chandra Deep Field South (ECDF-S). Using HST…
Kinematical trends among the field horizontal branch stars
Martin Altmann, Klaas S. de Boer
Field Horizontal branch (HB) stars can be used as tracers for the study of early stages of the evolution of our galaxy. Since the age of individual HB stars is not known a priori,…
First ground-based CCD proper motions for Fornax II: Final results
Rene. A. Mendez, Edgardo Costa, Carme Gallart +3
We present the first entirely ground-based astrometric determination of the proper motion for the Fornax Local Group Dwarf Spheroidal satellite galaxy of the Milky Way, using CCD d…
Meet the COG's
Martin Altmann, Marcio Catelan, Manuela Zoccali
Kinematics combined with detailed element abundances provide the method of analysis of stellar populations using as much available information as possible, in contrast to other met…
GBOT: ground based optical tracking of the Gaia satellite
Martin Altmann, Sebastien Bouquillon, Francois Taris +6
Gaia, the 1 billion star, high precision, astrometric satellite will revolutionise our understanding in many areas of astronomy ranging from bodies in our Solar System to the forma…
The stars near the centre of supergiant shell LMC4: Further constraints on triggering scenarios
Jochen M. Braun, Klaas S. de Boer, Martin Altmann
The huge supergiant shell (SGS) LMC4, next to the giant HII region 30 Doradus the second most impressive feature of the Large Magellanic Cloud (LMC), has been the subject of many s…