Search Publications
Cold dust in three massive evolved stars in the LMC
van Loon, J. Th.; Okumura, K.; Hony, S. +19 more
Massive evolved stars can produce large amounts of dust, and far-infrared (IR) data are essential for determining the contribution of cold dust to the total dust mass. Using Herschel, we search for cold dust in three very dusty massive evolved stars in the Large Magellanic Cloud: R71 is a luminous blue variable, HD 36402 is a Wolf-Rayet triple sys…
Estimating the masses of extra-solar planets
Dhillon, V. S.; Littlefair, S. P.; Collier Cameron, A. +2 more
All extra-solar planet masses that have been derived spectroscopically are lower limits since the inclination of the orbit to our line-of-sight is unknown except for transiting systems. In theory, however, it is possible to determine the inclination angle, i, between the rotation axis of a star and an observer's line-of-sight from measurements of …
X-ray spectroscopy of the hot gas in the M31 bulge
Wang, Q. Daniel; Liu, Jiren; Li, Zhiyuan +1 more
We present an X-ray spectroscopic study of the nuclear region of the M31 bulge, based on observations of the XMM-Newton Reflection Grating Spectrometers. The obtained high-resolution grating spectra clearly show individual emission lines of highly ionized iron and oxygen, which unambiguously confirm the presence of diffuse hot gas in the bulge, as…
870 µm observations of evolved stars with LABOCA
Blommaert, J. A. D. L.; Justtanont, K.; Barlow, M. J. +3 more
Context. During their evolution, asymptotic giant branch (AGB) stars experience a high mass loss which leads to the formation of a circumstellar envelope (CSE) of dust and gas. The mass loss process is the most important phenomenon during this evolutionary stage. In order to understand it, it is important to study the physical parameters of the CS…
The quest for the Sun's siblings: an exploratory search in the Hipparcos Catalogue
Brown, Anthony G. A.; Portegies Zwart, Simon F.; Bean, Jennifer
We describe the results of a search for the remnants of the Sun's birth cluster among stars in the Hipparcos Catalogue. This search is based on the predicted phase-space distribution of the Sun's siblings from simple simulations of the orbits of the cluster stars in a smooth Galactic potential. For stars within 100 pc, the simulations show that it…
Structure of the Earth’s circumsolar dust ring
Reach, William T.
Interplanetary dust particles from comets and asteroids pervade the Solar System and become temporarily trapped into orbital resonances with Earth, leading to a circumsolar dust ring. Using the unique vantage point of the Spitzer Space Telescope from its Earth-trailing solar orbit, we have measured for the first time the azimuthal structure of the…
Star formation history of KDG61 and KDG64 from spectroscopy and colour-magnitude diagrams
Makarova, Lidia; Makarov, Dmitry; Koleva, Mina +1 more
A study of two dE/dSph members of the nearby M81 group of galaxies, KDG61 and UGC5442 = KDG64, has been made. Direct Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) images and integrated-light spectra of 6-m telescope of Special Astrophysical Observatory of Russian Academy of Sciences have been used for quantitative star formation h…
Empirical Delay-time Distributions of Type Ia Supernovae from the Extended Goods/Hubble Space Telescope Supernova Survey
Riess, Adam G.; Strolger, Louis-Gregory; Dahlen, Tomas
Using the Hubble Space Telescope (HST) Advanced Camera for Surveys imaging of the GOODS North and South fields during Cycles 11, 12, and 13, we derive empirical constraints on the delay-time distribution function for type Ia supernovae (SNe Ia). We extend our previous analysis to the three-year sample of 56 SNe Ia over the range 0.2 < z < 1.…
Suzaku Observations of Luminous Quasars: Revealing the Nature of High-energy Blazar Emission in Low-level Activity States
Maraschi, L.; Ozaki, M.; Frailis, M. +171 more
We present the results from the Suzaku X-ray observations of five flat-spectrum radio quasars (FSRQs), namely PKS 0208-512, Q 0827+243, PKS 1127-145, PKS 1510-089, and 3C 454.3. All these sources were additionally monitored simultaneously or quasi-simultaneously by the Fermi satellite in gamma rays and the Swift UVOT in the UV and optical bands, r…
SAO RAS 6-m telescope spectroscopic observations of globular clusters in nearby galaxies
Chandar, Rupali; Goudfrooij, Paul; Puzia, Thomas H. +2 more
We present the results of medium-resolution spectroscopy of 28 globular clusters (GCs) in six nearby galaxies of different luminosities and morphological types, situated in M33 (15 objects), M31 (three), IC10 (four), UGCA86 (four), Holmberg IX (one) and DDO71 (one) obtained at the Special Astrophysical Observatory 6-m telescope. Measurements of Li…