Search Publications
Investigating the origin of the spectral line profiles of the Hot Wolf-Rayet Star WR 2
Crowther, P. A.; Wade, G. A.; Chené, A. -N. +12 more
The hot WN star WR 2 (HD 6327) has been claimed to have many singular characteristics. To explain its unusually rounded and relatively weak emission line profiles, it has been proposed that WR 2 is rotating close to break-up with a magnetically confined wind. Alternatively, the line profiles could be explained by the dilution of WR 2's spectrum by…
The 3D shape of Type IIb SN 2011hs
Spyromilio, J.; Wang, L.; Wheeler, J. C. +10 more
We observed seven epochs of spectropolarimetry in optical wavelengths for the Type IIb SN 2011hs, ranging from -3 to +40 d with respect to V-band maximum. A high degree of interstellar polarization was detected (up to ∼3 per cent), with a peak lying blueward of 4500 Å. Similar behaviours have been seen in some Type Ia supernovae (SNe), but had nev…
Transit analysis of the CoRoT-5, CoRoT-8, CoRoT-12, CoRoT-18, CoRoT-20, and CoRoT-27 systems with combined ground- and space-based photometry
Heras, A. M.; Casanova, V.; Fernández, M. +2 more
We have initiated a dedicated project to follow-up with ground-based photometry the transiting planets discovered by CoRoT in order to refine the orbital elements, constrain their physical parameters, and search for additional bodies in the system. From 2012 September to 2016 December we carried out 16 transit observations of six CoRoT planets (Co…
The true nature of Swift J0746.3-1608: a possible Intermediate Polar showing accretion state changes
Mukai, K.; de Martino, D.; Bernardini, F. +1 more
Optical and X-ray observations suggested that the 9.38 h binary, SWIFT J0746.3-1608 could be a cataclysmic variable (CV) of the magnetic or nova-like type, or a low-mass X-ray binary. Its optical, UV, and X-ray light curves are strongly variable over years. We report on a recent XMM-Newton observation (2018 April 28), when the source had recovered…
Long-term stellar variability in the Galactic Centre region
Minniti, D.; Catelan, M.; Lucas, P. W. +5 more
We report the detection of variable stars within a 11.5 arcmin× 11.5 arcmin region near the Galactic Centre that includes the Arches and Quintuplet clusters, as revealed by the VISTA Variables in the Vía Láctea survey. There are 353 sources that show KS-band variability, of which the large majority (81 per cent) correspond to red giant …
The GALAH survey: a catalogue of carbon-enhanced stars and CEMP candidates
Lewis, Geraint F.; Ting, Yuan-Sen; Buder, Sven +20 more
Swan bands - characteristic molecular absorption features of the C2 molecule - are a spectroscopic signature of carbon-enhanced stars. They can also be used to identify carbon-enhanced metal-poor (CEMP) stars. The GALAH (GALactic Archaeology with Hermes) is a magnitude-limited survey of stars producing high-resolution, high-signal-to-no…
On the possibility of detecting ultrashort period exoplanets with LISA
Wong, Kaze W. K.; Berti, Emanuele; Gabella, William E. +1 more
Cunha, Silva & Lima recently reexamined the possibility of detecting gravitational waves from exoplanets, claiming that three ultrashort period systems would be observable by LISA. We revisit their analysis and conclude that the currently known exoplanetary systems are unlikely to be detectable, even assuming a LISA observation time Tobs<…
Spectroscopic confirmation and modelling of two lensed quadruple quasars in the Dark Energy Survey public footprint
Marchetti, L.; Vaccari, M.; Baker, A. J. +12 more
Quadruply lensed quasars are extremely rare objects, but incredibly powerful cosmological tools. Only few dozen are known in the whole sky. Here we present the spectroscopic confirmation of two new quadruplets WG0214-2105 and WG2100-4452 discovered by Agnello & Spiniello (2018) within the Dark Energy Survey public footprints. We have conducted…
Probing the fluctuating ultraviolet background using the Hubble Frontier Fields
Dayal, Pratika; Choudhury, Tirthankar Roy
In recent years, the rise in the number of Lyman Break Galaxies detected at high redshifts z ≥ 6 has opened up the possibility of understanding early galaxy formation physics in great detail. In particular, the faint-end slope (α) of the ultraviolet luminosity function (UV LF) of these galaxies is a potential probe of feedback effects that suppres…
CPD-64°2731: a massive spun-up and rejuvenated high-velocity runaway star
Katkov, I. Y.; Gvaramadze, V. V.; Castro, N. +4 more
We report the results of our study of the high-velocity ({≈ }160 km s^{-1}) runaway O star CPD-64°2731 and its associated horseshoe-shaped nebula discovered with the Wide-field Infrared Survey Explorer. Spectroscopic observations with the Southern African Large Telescope and spectral analysis indicate that CPD-64°2731 is a fast-rotating main-seque…