Search Publications
A black box for dark sector physics: predicting dark matter annihilation feedback with conditional GANs
Lewis, Geraint F.; List, Florian; Bhat, Ishaan
Traditionally, incorporating additional physics into existing cosmological simulations requires re-running the cosmological simulation code, which can be computationally expensive. We show that conditional Generative Adversarial Networks (cGANs) can be harnessed to predict how changing the underlying physics alters the simulation results. To illus…
Asteroseismic constraints on active latitudes of solar-type stars: HD 173701 has active bands at higher latitudes than the Sun
Chaplin, William J.; Davies, Guy R.; Miglio, Andrea +6 more
We present a new method for determining the location of active bands of latitude on solar-type stars, which uses stellar-cycle-induced frequency shifts of detectable solar-like oscillations. When near-surface activity is distributed in a non-homogeneous manner, oscillation modes of different angular degree and azimuthal order will have their frequ…
A magnetic white dwarf with five H α components
Bergeron, P.; Kilic, Mukremin; Vanderbosch, Z. +3 more
G183-35 is an unusual white dwarf that shows an H α line split into five components, instead of the usual three components seen in strongly magnetic white dwarfs. Potential explanations for the unusual set of lines include a double degenerate system containing two magnetic white dwarfs and/or rotational modulation of a complex magnetic field struc…
Discovery of recombining plasma inside the extended gamma-ray supernova remnant HB9
Fukui, Y.; Sano, H.; Sezer, A. +2 more
We present the results from the Suzaku X-ray Imaging Spectrometer observation of the mixed-morphology supernova remnant (SNR) HB9 (G160.9+2.6). We discovered recombining plasma (RP) in the western Suzaku observation region and the spectra here are well described by a model having collisional ionization equilibrium (CIE) and RP components. On the o…
Heavy negative ion growth in Titan's polar winter
Coates, A. J.; Jones, G. H.; Wellbrock, A. +4 more
A significant but unexpected result of the Cassini mission was the discovery of heavy organic negative ions in Titan's ionosphere at altitudes between about 950 and 1400 km by the CAPS Electron Spectrometer (ELS). The heaviest ions were observed during the T16 fly-by with masses over 13 000 u/q. This is significantly higher than the maximum masses…
Supergiant Fast X-ray Transients uncovered by the EXTraS project: flares reveal the development of magnetospheric instability in accreting neutron stars
Esposito, Paolo; Belfiore, Andrea; Salvaterra, Ruben +5 more
The low luminosity, X-ray flaring activity, of the sub-class of high-mass X-ray binaries called Supergiant Fast X-ray Transients, has been investigated using XMM-Newton public observations, taking advantage of the products made publicly available by the EXTraS project. One of the goals of EXTraS was to extract from the XMM-Newton public archive in…
The signal of decaying dark matter with hydrodynamical simulations
Lovell, Mark R.; Crain, Robert A.; Schaye, Joop +11 more
Dark matter particles may decay, emitting photons. Drawing on the EAGLE family of hydrodynamical simulations of galaxy formation - including the APOSTLE and C-EAGLE simulations - we assess the systematic uncertainties and scatter on the decay flux from different galaxy classes, from Milky Way satellites to galaxy clusters, and compare our results …
Broad-band X-ray analysis of local mid-infrared-selected Compton-thick AGN candidates
Pozzi, F.; Vignali, C.; Gruppioni, C. +2 more
The estimate of the number and space density of obscured active galactic nuclei (AGNs) over cosmic time still represents an open issue. While the obscured AGN population is a key ingredient of the X-ray background synthesis models and is needed to reproduce its shape, a complete census of obscured AGN is still missing. Here we test the selection o…
A SINFONI view of the nuclear activity and circumnuclear star formation in NGC 4303 - II. Spatially resolved stellar populations
Colina, L.; Burtscher, L.; Pastoriza, M. G. +11 more
We present a spatially resolved stellar population study of the inner ∼200 pc radius of NGC 4303 based on near-infrared integral field spectroscopy with SINFONI/VLT at a spatial resolution of 40-80 pc and using the STARLIGHT code. We found that the distribution of the stellar populations presents a spatial variation, suggesting an age stratificati…
Kinematic signatures of cluster formation from cool collapse in the Lagoon Nebula cluster NGC 6530
Parker, Richard J.; Wright, Nicholas J.
We examine the mass dependence of the velocity dispersion of stars in the young cluster NGC 6530 to better understand how it formed. Using a large sample of members we find that the proper motion velocity dispersion increases with stellar mass. While this trend is the opposite of that predicted if the cluster were developing energy equipartition, …