Search Publications
Time series analysis of bright TESS RRc stars: additional modes, phase variations, and more
Pál, A.; Plachy, E.; Molnár, L. +3 more
Using two years of data from the TESS space telescope, we have investigated the time series of 633 overtone pulsating field RR Lyrae (RRc) stars. The majority of stars (82.8 per cent) contain additional frequencies beyond the main pulsation. In addition to the frequencies previously explained by the ℓ = 8 and 9 non-radial modes, we have identified…
Unravelling the mass spectrum of destroyed dwarf galaxies with the metallicity distribution function
Grand, Robert J. J.; Fattahi, Azadeh; Koposov, Sergey E. +1 more
Accreted stellar populations are comprised of the remnants of destroyed galaxies, and often dominate the 'stellar haloes' of galaxies such as the Milky Way (MW). This ensemble of external contributors is a key indicator of the past assembly history of a galaxy. We introduce a novel statistical method that uses the unbinned metallicity distribution…
Bayesian sampling with BeAtlas, a grid of synthetic Be star spectra I. Recovering the fundamental parameters of α Eri and β CMi
Carciofi, A. C.; de Amorim, T. H.; Vieira, R. G. +14 more
Classical B emission (Be) stars are fast rotating, near-main-sequence B-type stars. The rotation and the presence of circumstellar discs profoundly modify the observables of active Be stars. Our goal is to infer stellar and disc parameters, as well as distance and interstellar extinction, using the currently most favoured physical models for these…
Spectroscopic and photometric studies on four solar-type short-period contact binaries in the triple stellar systems
Michel, Raúl; Wang, Shuang; Yang, Yuangui +2 more
We reported new spectroscopy and photometry for four short-period binaries, which were acquired by several small telescopes in China from 2020 to 2022. From new spectrum and Large Sky Area Multiobject Fiber Spectroscopic Telescope data, we determined their spectral types of G8V for PZ UMa, G7 for MM Com, and V0685 Peg and G3 for V1055 Her. When co…
The GALAH survey: new diffuse interstellar bands found in residuals of 872 000 stellar spectra
Lewis, Geraint F.; Buder, Sven; Bland-Hawthorn, Joss +11 more
We use more than 872 000 mid- to high-resolution (R ~ 20 000) spectra of stars from the GALactic Archaeology with HERMES (GALAH) survey to discern the spectra of diffuse interstellar bands (DIBs). We use four windows with the wavelength ranges 4718-4903, 5649-5873, 6481-6739, and 7590-7890 Å, giving a total coverage of 967 Å. We produce ~400 000 s…
Measuring the streaming motion in the Milky Way disc with Gaia EDR3+
Bland-Hawthorn, Joss; Sharma, Sanjib; Khanna, Shourya +1 more
We map the 3D kinematics of the Galactic disc out to 3.5 kpc from the Sun, and within 0.75 kpc from the mid-plane of the Galaxy. To this end, we combine high-quality astrometry from Gaia EDR3, with heliocentric line-of-sight velocities from Gaia DR2, and spectroscopic surveys including APOGEE, GALAH, and LAMOST. We construct an axisymmetric model …
Accelerating galaxy winds during the big bang of starbursts
Hayes, Matthew J.
We develop a new method to infer the temporal, geometric, and energetic properties of galaxy outflows, by combining stellar spectral modelling to infer starburst ages, and absorption lines to measure velocities. If winds are accelerated with time during a starburst event, then these two measurements enable us to solve for the wind radius, similarl…
Unveiling the nitrogen-rich massive star in the metal-poor galaxy NGC 4068
Egorov, Oleg V.; Yarovova, Anastasiya D.; Moiseev, Alexei V. +1 more
We report the identification of the unusual emission-line stellar-like object in the nearby low-metallicity ($Z \sim 0.1 \, \mathrm{Z_{\odot }}$) dwarf galaxy NGC 4068. Our observations performed with long-slit spectrograph and Fabry-Perot interferometer demonstrate high velocity dispersion in H α line, presence of He II λ4686Å line and peculiarly…
Another look at the dayside spectra of WASP-43b and HD 209458b: Are there scattering clouds?
Parmentier, Vivien; Taylor, Jake
The search for clouds on the dayside of hot Jupiters has been disadvantaged due to the limited number of high quality space-based observations of their dayside. To date, retrieval studies have found no evidence for grey clouds on the dayside, however none of these studies explored the impact of scattering clouds. In this study we reanalyse the day…
Assessing the physical reality of Milky Way open cluster candidates
Piatti, Andrés E.; Illesca, Denis M. F.; Massara, Agustina A. +4 more
We report results on the analysis of 11 new Milky Way open cluster candidates, recently discovered from the detection of stellar overdensities in the Vector Point diagram, by employing Xtreme deconvolution Gaussian mixture models. We treated these objects as real open clusters and derived their fundamental properties with their associated intrinsi…