Search Publications
An interferometric SETI observation of Kepler-111 b
Gajjar, Vishal; Garrett, Michael A.; Wandia, Kelvin +8 more
The application of very long baseline interferometry (VLBI) to the search for extraterrestrial intelligence (SETI) has been limited to date, despite the technique offering many advantages over traditional single-dish SETI observations. In order to further develop interferometry for SETI, we used the European VLBI network (EVN) at 21 cm to observe …
An astrometric approach to measuring the colour of an object
Lin, F. R.; Peng, Q. Y.; Guo, B. F. +1 more
The colour of a star is a critical feature to reflect its physical property such as the temperature. The colour index is usually obtained via absolute photometry, which is demanding for weather conditions and instruments. In this work, we present an astrometric method to measure the catalogue-matched colour index of an object based on the effect o…
Photometric calibration in u-band using blue halo stars
von der Linden, Anja; Liang, Shuang
We develop a method to calibrate u-band photometry based on the observed colour of blue Galactic halo stars. The Galactic halo stars belong to an old stellar population of the Milky Way and have relatively low metallicity. The 'blue tip' of the halo population - the main sequence turn-off (MSTO) stars - is known to have a relatively uniform intrin…
Confirmation of two magnetic cataclysmic variables as polars: 1RXS J174320.1-042953 and YY Sex
Pandey, J. C.; Potter, Stephen B.; De Becker, Michaël +5 more
We present our analysis of new and archived observations of two candidate magnetic cataclysmic variables, namely 1RXS J174320.1-042953 and YY Sex. 1RXS J174320.1-042953 was observed in two distinctive high and low states where a phase shift was seen, which could be due to changes in the shape, size, and (or) location of the accretion region. We fi…
The common fundamental plane of X-ray emissions from pulsars and magnetars in quiescence
Chang, Hsiang-Kuang; Chu, Che-Yen
Magnetars are a unique class of neutron stars characterized by their incredibly strong magnetic fields. Unlike normal pulsars whose X-ray emission was driven by rotational energy loss, magnetars exhibit distinct X-ray emissions thought to be driven by their strong magnetic fields. Here, we present the results of magnetar X-ray spectra analysis in …
Fundamental properties of red giants from Kepler and Gaia DR3 data: diagnostic potential of the mass-metallicity diagram
Yıldız, M.
For solar-like oscillators, the asteroseismic relations connect the stellar mean density and surface gravity to observable properties of the oscillations. Since the space missions CoRoT and Kepler, the asteroseismic relations have been massively employed out of their theoretical domain of validity, that is the main-sequence solar-type stars, in pa…
Kilometer-precise (UII) Umbriel physical properties from the multichord stellar occultation on 2020 September 21
Smith, N.; Sicardy, B.; Gomes-Júnior, A. R. +39 more
We report the results of the stellar occultation by (UII) Umbriel on 2020 September 21. The shadow crossed the USA and Canada, and 19 positive chords were obtained. A limb parameter accounted for putative topographic features in the limb fittings. Ellipse fittings were not robust - only upper limits were derived for the true size/shape of a putati…
AGN candidates in the VVV near-IR galaxy catalogue
Smith, Leigh C.; Minniti, Dante; Alonso, M. Victoria +7 more
The goal of this work is to search for Active Galactic Nuclei (AGN) in the Galactic disc at very low latitudes with |b| < 2°. For this, we studied the five sources from the VVV near-infrared (IR) galaxy catalogue that have also WISE counterparts and present variability in the VIrac VAriable Classification Ensemble (VIVACE) catalogue. In the nea…
Simulation of Phobos gravity field estimation from Tianwen-1 flybys and implications for the modelling of Phobos' internal structure
Liu, L.; Chen, Y. H.; Guo, X. +4 more
Doppler radio tracking data from Tianwen-1, China's first Mars mission, could contribute to a better estimate of the gravity field of Phobos. In this study, we show that a determination up to degree and order 3 is feasible by considering five additional flybys of Phobos by the Tianwen-1 spacecraft, in addition to the previous flybys already done b…
Discovery of periodic hot subdwarf variables through a systematic search in Zwicky Transient Facility data
Kupfer, Thomas; Barlow, Brad N.; Wang, Kevin
We conduct a systematic search for periodic variables in the hot subdwarf catalogue using data from the Zwicky Transient Facility. We present the classification of 67 HW Vir binaries, 496 reflection effect, pulsation or rotation sinusoids, 11 eclipsing signals, and 4 ellipsoidally modulated binaries. Of these, 486 are new discoveries that have not…