Search Publications
X-ray bounds on the r-mode amplitude in millisecond pulsars
Güver, Tolga; Vurgun, Eda; Schwenzer, Kai +1 more
r-mode asteroseismology provides a unique way to study the internal composition of compact stars. Due to their precise timing, recycled millisecond radio pulsars present a particularly promising class of sources. Although their thermal properties are still poorly constrained, X-ray data is very useful for asteroseismology since r-modes could stron…
Predictions for the detection of tidal streams with Gaia using great-circle methods
Wang, Wenting; Cole, Shaun; Aguilar, Luis +5 more
The Gaia astrometric mission may offer an unprecedented opportunity to discover new tidal streams in the Galactic halo. To test this, we apply nGC3, a great-circle-cell count method that combines position and proper motion data to identify streams, to 10 mock Gaia catalogues of K giants and RR Lyrae stars constructed from cosmological simulations …
Modelling the size of the very dynamic diamagnetic cavity of comet 67P/Churyumov-Gerasimenko
Szego, K.; Goetz, C.; Richter, I. +5 more
After the first detection of the diamagnetic cavity of comet 67P/Churyumov-Gerasimenko, it became apparent that the boundary of this plasma region is very dynamic. To date hundreds of short cavity crossing events were detected, none lasting longer than an hour. This intermittent set of short events is very different from the classical cavity obser…
Precise CCD positions of Triton in 2014-2016 using the newest Gaia DR1 star catalogue
Wang, N.; Peng, Q. Y.; Xie, H. J. +3 more
755 new CCD observations during the years 2014-2016 have been reduced to derive the precise positions of Triton, the first satellite of Neptune. The observations were made by the 1-m telescope at Yunnan Observatory over 15 nights. The positions of Triton are measured with respect to the stars in Gaia DR1 star catalogue. The theoretical position of…
Ultracool dwarf benchmarks with Gaia primaries
Gromadzki, M.; Caballero, J. A.; Montes, D. +14 more
We explore the potential of Gaia for the field of benchmark ultracool/brown dwarf companions, and present the results of an initial search for metal-rich/metal-poor systems. A simulated population of resolved ultracool dwarf companions to Gaia primary stars is generated and assessed. Of the order of ∼24 000 companions should be identifiable outsid…
SXP 15.6: X-ray spectral and temporal properties of a newly discovered pulsar in the Small Magellanic Cloud
Haberl, F.; Zezas, A.; Antoniou, V. +1 more
We report on the X-ray spectral and temporal properties of the Be/X-ray binary system XMMU J004855.5-734946 located in the Small Magellanic Cloud. The system was monitored by Swift/XRT during a moderate outburst in 2016 July, while an unanticipated Chandra target of opportunity observation was triggered when the luminosity of the system was greate…
A series of shocks and edges in Abell 2219
von der Linden, A.; Allen, S. W.; Russell, H. R. +6 more
We present deep, 170 ks, Chandra X-ray observations of Abell 2219 (z = 0.23), one of the hottest and most X-ray luminous clusters known, and which is experiencing a major merger event. We discover a `horseshoe' of high-temperature gas surrounding the ram-pressure-stripped, bright, hot, X-ray cores. We confirm an X-ray shock front located north-wes…
On the silicate crystallinities of oxygen-rich evolved stars and their mass-loss rates
Gao, Jian; Li, Aigen; Liu, Jiaming +1 more
For decades ever since the early detection in the 1990s of the emission spectral features of crystalline silicates in oxygen-rich evolved stars, there is a long-standing debate on whether the crystallinity of the silicate dust correlates with the stellar mass-loss rate. To investigate the relation between the silicate crystallinities and the mass-…
Highly dynamically evolved intermediate-age open clusters
Piatti, Andrés E.; Dias, Wilton S.; Sampedro, Laura M.
We present a comprehensive UBVRI and Washington CT1T2 photometric analysis of seven catalogued open clusters, namely: Ruprecht 3, 9, 37, 74, 150, ESO 324-15 and 436-2. The multiband photometric data sets in combination with 2MASS photometry and Gaia astrometry for the brighter stars were used to estimate their structural para…
High-resolution Spectroscopy and Spectropolarimetry of Selected δ-Sct Pulsating Variables
Joshi, Y. C.; Joshi, Santosh; Singh, Harinder P. +5 more
The combination of photometry, spectroscopy and spectropolarimetry of the chemically peculiar stars often aims to study the complex physical phenomena such as stellar pulsation, chemical inhomogeneity, magnetic field and their interplay with stellar atmosphere and circumstellar environment. The prime objective of this study is to determine the atm…