Search Publications
Classifying the satellite plane membership of Centaurus A's dwarf galaxies using orbital alignment constraints
Müller, Oliver; Sohn, Sangmo Tony; Pawlowski, Marcel S. +1 more
The flattened, possibly co-rotating plane of satellite galaxies around Centaurus A, if more than a fortuitous alignment, adds to the pre-existing tension between the well-studied Milky Way and M31 planes and the Lambda cold dark matter model of structure formation. It was recently reported that the Centaurus A satellite plane (CASP) may be rotatio…
Detection of H I 21 cm emission from a strongly lensed galaxy at z 1.3
Roy, Nirupam; Chakraborty, Arnab
We report the first 5σ detection of H I 21 cm emission from a star-forming galaxy at redshift z ~ 1.3 (nearly 9 billion years ago) using upgraded Giant Metrewave Radio Telescope (uGMRT). This is the highest redshift H I detection in emission from an individual galaxy to date. The emission is strongly boosted by the gravitational lens, an early-typ…
Gaia21bty: An EXor light curve exhibiting a FUor spectrum
Udalski, Andrzej; Moór, Attila; Ábrahám, Péter +16 more
Gaia21bty, a pre-main-sequence star that previously had shown aperiodic dips in its light curve, underwent a considerable ΔG ≈ 2.9 mag brightening that occurred over a few months between 2020 October and 2021 February. The Gaia light curve shows that the star remained near maximum brightness for about 4-6 months, and then started slowly fading ove…
Residuals of an equilibrium model for the galaxy reveal a state of disequilibrium in the Solar Neighbourhood
Widrow, Lawrence M.; Li, Haochuan
We simultaneously model the gravitational potential and phase space distribution function (DF) of giant stars near the Sun using the Gaia DR2 radial velocity catalogue. We assume that the Galaxy is in equilibrium and is symmetric about both the spin axis of the disc and the Galactic mid-plane. The potential is taken as a sum of terms that nominall…
Sensitivity of modelled cometary gas production on the properties of the surface layer of the nucleus
Küppers, M.; Hartogh, P.; Besse, S. +3 more
Explanation of the observed gas activity based on the parameters of the comet's nucleus is not an obvious matter. Solutions based on certain thermal models can be obtained, but the use of arbitrary values for poorly known model parameters is always required. In this work, we carry out a study of the dependence of gas activity on these parameters a…
In situ or accreted? Using deep learning to infer the origin of extragalactic globular clusters from observables
Kruijssen, J. M. Diederik; Trujillo-Gomez, Sebastian; Crain, Robert A. +4 more
Globular clusters (GCs) are powerful tracers of the galaxy assembly process, and have already been used to obtain a detailed picture of the progenitors of the Milky Way (MW). Using the E-MOSAICS cosmological simulation of a (34.4 Mpc)3 volume that follows the formation and co-evolution of galaxies and their star cluster populations, we …
The HST large programme on NGC 6752 - IV. The White Dwarf sequence
Salaris, M.; Apai, D.; Anderson, J. +13 more
We present our final study of the white dwarf cooling sequence (WD CS) in the globular cluster NGC 6752. The investigation is the main goal of a dedicated Hubble Space Telescope large program, for which all the observations are now collected. The WD CS luminosity function (LF) is confirmed to peak at mF606W ≃ 29.3 ± 0.1, consistent with…
An HST COS ultraviolet spectroscopic survey of 311 DA white dwarfs - I. Fundamental parameters and comparative studies
Hermes, J. J.; Redfield, Seth; Sahu, Snehalata +8 more
White dwarf studies carry significant implications across multiple fields of astrophysics, including exoplanets, supernova explosions, and cosmological investigations. Thus, accurate determinations of their fundamental parameters (Teff and log g) are of utmost importance. While optical surveys have provided measurements for many white d…
Spectroscopic survey of faint planetary-nebula nuclei - I. Six new 'O VI' central stars
Bond, Howard E.; Zeimann, Gregory R.; Werner, Klaus +1 more
We report initial results from an ongoing spectroscopic survey of central stars of faint planetary nebulae (PNe), obtained with the Low-Resolution Spectrograph on the Hobby-Eberly Telescope. The six PN nuclei (PNNi) discussed here all have strong emission at the O VI 3811-3834 Å doublet, indicative of very high temperatures. Five of them - the nuc…
Spatially resolved mock observations of stellar kinematics: full radiative transfer treatment of simulated galaxies
Straatman, Caroline M. S.; van der Wel, Arjen; Bezanson, Rachel +6 more
We present a framework to build realistic mock spectroscopic observations for state-of-the-art hydrodynamical simulations, using high spectral resolution stellar population models and full radiative transfer treatment with SKIRT. As a first application, we generate stellar continuum mock observations for the Auriga cosmological zoom simulations em…