Search Publications
An O2 If*/WN6 star caught in the act in a compact H II region in the starburst cluster NGC 3603
Roman-Lopes, A.
In this paper, we report on the discovery of an O2 If*/WN6 star probably still partially embedded in its parental cocoon in the starburst cluster NGC 3603. From the observed size of the associated compact H II region, it has been possible to derive a probable dynamic age of no more than 600 000 yr. Using the computed visual extinction value A…
Orbital motion of the binary brown dwarf companions HD 130948 BC around their host star
Neuhäuser, R.; Schmidt, T. O. B.; Ginski, C. +2 more
Evolutionary models and mass estimates for brown dwarfs remain uncertain, hence determining the masses of brown dwarfs by model-independent methods is important to test and constrain such theories. Following the orbital motion of brown dwarf companions around their primaries gives us the opportunity to dynamically calculate the masses of these sys…
The Herschel Virgo Cluster Survey - XIV. Transition-type dwarf galaxies in the Virgo cluster
Zibetti, Stefano; De Looze, Ilse; Baes, Maarten +19 more
We use dust scaling relations to investigate the hypothesis that Virgo cluster transition-type dwarfs are infalling star-forming field galaxies, which is argued based on their optical features (e.g. discs, spiral arms and bars) and kinematic properties similar to late-type galaxies. After their infall, environmental effects gradually transform the…
Calibration of RAVE distances to a large sample of Hipparcos stars
Francis, Charles
A magnitude-limited population of 18 808 Hipparcos stars is used to calibrate distances for 52 794 RAdial Velocity Experiment (RAVE) stars, including dwarfs, giants and pre-main-sequence stars. I give treatments for a number of types of bias affecting calculation, including bias from the non-linear relationship between the quantity of interest (e.…
On the progenitor of the type IC SN 2013dk in the antennae galaxies.
Smartt, S. J.; Benetti, S.; Maund, J. R. +7 more
We report the results of our search for the progenitor candidate of SN 2013dk, a Type Ic supernova (SN) that exploded in the Antennae galaxy system. We compare pre-explosion Hubble Space Telescope (HST) archival images with SN images obtained using adaptive optics at the ESO Very Large Telescope. We isolate the SN position to within 3σ uncertainty…
Multichromatic colour-magnitude diagrams of the globular cluster NGC 6366
Kepler, S. O.; Bonatto, C.; Campos, Fabíola +1 more
We present multichromatic isochrone fits to the colour-magnitude data of the globular cluster NGC 6366, based on Hubble Space Telescope Advanced Camera for Surveys/Wide Field Channel and Southern Astrophysical Research photometric data. We corrected the photometric data for differential reddening and calculated the mean ridge line of the colour-ma…
High-redshift Fermi blazars observed by GROND and Swift
Ghirlanda, G.; Ghisellini, G.; Tavecchio, F. +6 more
We observed five γ-ray-loud blazars at redshift greater than 2 with the X-Ray Telescope (XRT) and the UltraViolet and Optical Telescope (UVOT) on-board the Swift satellite, and the Gamma-Ray burst Optical Near-Infrared Detector (GROND) instrument. These observations were quasi-simultaneous, usually within a few hours. For four of these blazars, th…
Polarimetric studies of comet C/2009 P1 (Garradd)
Wolf, S.; Medhi, B. J.; Das, H. S. +3 more
We present the optical imaging polarimetric observations of comet C/2009 P1 (Garradd) at three different phase angles e.g. 28.2°, 28.1° and 21.6°. The observations were carried out using the Inter University Centre for Astronomy and Astrophysics (IUCAA) Faint Object Spectrograph and Camera mounted on Cassegrain focus of the 2 m telescope of IGO, I…
The planetary nebulae population in the nuclear regions of M31: the SAURON view
Bacon, Roland; Emsellem, Eric; Sarzi, Marc +5 more
The study of extragalactic planetary nebulae (PNe) in the optical regions of galaxies, where the properties of their stellar population can be best characterized, is a promising ground to better understand the late evolution of stars across different galactic environments. Following a first study of the central regions of M32 that illustrated the …
Spin and spectral variations of a peculiar high-mass X-ray binary 4U 2206+54
Wang, Wei
Spin properties and spectral variations of a high-mass X-ray binary 4U 2206+54 are studied with long-term hard X-ray monitoring observations by INTEGRAL. A long-period X-ray pulsar of Pspin ∼ 5558 s has been identified in 4U 2206+54. The spin evolution of the neutron star in 4U 2206+54 is detected with the INTEGRAL/IBIS data. From 2005 …