Search Publications
The largest bright ULX population in a galaxy: X-ray variability and luminosity function in the Cartwheel ring galaxy
Wolter, A.; Belfiore, A.; Salvaggio, Chiara +1 more
We analyse all the available Chandra observations of the Cartwheel galaxy and its compact group, taken between 2001 and 2008, with the main aim of addressing the variability in the X-ray band for this spectacular collisional ring galaxy. We focus on the study of point-like sources, in particular we are interested in ultraluminous X-ray sources (UL…
Properties and asteroseismological analysis of a new ZZ ceti discovered by TMTS
Shi, Jianrong; Filippenko, Alexei V.; Esamdin, Ali +24 more
Tsinghua University-Ma Huateng Telescope for Survey (TMTS) aims to discover rapidly evolving transients by monitoring the northern sky. The TMTS catalogue is cross-matched with the white dwarf (WD) catalogue of Gaia EDR3, and light curves of more than a thousand WD candidates are obtained so far. Among them, the WD TMTS J23450729+5813146 is one in…
The origin of ultramassive white dwarfs: hints from Gaia EDR3
Caiazzo, Ilaria; Heyl, Jeremy; Fleury, Leesa
Gaia Data Release 2 revealed a population of ultramassive white dwarfs on the Q branch that are moving anomalously fast for a local disc population with their young photometric ages. As the velocity dispersion of stars in the local disc increases with age, a proposed explanation of these white dwarfs is that they experience a cooling delay that ca…
Resolved low-J12CO excitation at 190 parsec resolution across NGC 2903 and NGC 3627
Chevance, M.; Dale, D. A.; Schinnerer, E. +14 more
The low-J rotational transitions of 12CO are commonly used to trace the distribution of molecular gas in galaxies. Their ratios are sensitive to excitation and physical conditions in the molecular gas. Spatially resolved studies of CO ratios are still sparse and affected by flux calibration uncertainties, especially since most do not ha…
Fundamental effective temperature measurements for eclipsing binary stars - IV. Selection of new benchmark stars and first results for HD 22064
Maxted, Pierre F. L.
I describe the selection and initial characterization of 20 eclipsing binary stars that are suitable for calibration and testing of stellar models and data analysis algorithms used by the PLATO mission and spectroscopic surveys. The binary stars selected are F-/G-type dwarf stars with M-type dwarf companions that contribute less than 2 per cent of…
Cold molecular gas outflow encasing the ionized one in the Seyfert galaxy NGC 3281
Storchi-Bergmann, Thaisa; Riffel, Rogemar A.; Morganti, Raffaella +2 more
We present ALMA CO (2-1) observations of the Seyfert 2 galaxy NGC 3281 at ~100 pc spatial resolution. This galaxy was previously known to present a bi-conical ionized gas outflow extending to 2 kpc from the nucleus. The analysis of the CO moment and channel maps, as well as kinematic modelling, reveals two main components in the molecular gas: one…
DMPP-4: candidate sub-Neptune mass planets orbiting a naked-eye star
Anglada-Escudé, G.; Fossati, L.; Llama, J. +9 more
We present radial velocity measurements of the very bright (V ~ 5.7) nearby F star, DMPP-4 (HD 184960). The anomalously low Ca II H&K emission suggests mass-loss from planets orbiting a low activity host star. Periodic radial velocity variability with ~10 m s-1 amplitude is found to persist over a >4 yr time-scale. Although the n…
Doppler confirmation of TESS planet candidate TOI-1408.01: grazing transit and likely eccentric orbit
Galazutdinov, G. A.; Korablev, O.; Yakunin, I. +16 more
We report an independent Doppler confirmation of the TESS planet candidate orbiting an F-type main-sequence star TOI-1408 located 140 pc away. We present a set of radial velocities obtained with a high-resolution fibre-optic spectrograph FFOREST mounted at the SAO RAS 6-m telescope (BTA-6). Our self-consistent analysis of these Doppler data and TE…
VFTS 243 as predicted by the BPASS fiducial models
Eldridge, J. J.; Stevance, H. F.; Ghodla, S. +3 more
The recent discovery of an unambiguous quiescent black hole (BH) and main-sequence O star companion in VFTS 243 opens the door to new constraints on theoretical stellar evolution and population models looking to reproduce the progenitors of BH-BH binaries. Here, we show that the binary population and spectral synthesis fiducial models natively pre…
Characterizing abundance-age relations of GALAH stars using oxygen-enhanced stellar models
Wu, Yaqian; Xiang, Maosheng; Bi, Shaolan +3 more
Main-sequence turn-off (MSTO) stars and subgiant stars are good tracers of Galactic populations. We present a study of 41 034 MSTO and subgiant stars from the GALAH survey. Using a grid of stellar models that accounts for the variation of O abundances, we determine their ages with a median age uncertainty of ~9.4 per cent. Our analysis reveals tha…