Search Publications
New observations of DW Cnc: where is the 38 min signal?
Ramírez, S. H.; Echevarría, J.; Segura Montero, O.
We present extensive radial velocity observations of the intermediate polar DW Cnc during its 2018-2019 low state. We show that the 86 min signal associated with the orbital period is strong in our radial velocity analysis, power spectrum search, and in our Doppler tomography. However, we find that the velocity modulation associated with the 70 mi…
Discovery of a retrogradely rotating neutron star in the X-ray pulsar GX 301-2
Doroshenko, Victor; Tsygankov, Sergey S.; Poutanen, Juri +3 more
We report on the analysis of the spin evolution of a slow X-ray pulsar GX 301-2 along the orbit using long-term monitoring by Fermi/Gamma-ray Burst Monitor. Based on the observationally confirmed accretion scenario and an analytical model for the accretion of angular momentum, we demonstrate that in this system, the neutron star spins retrogradely…
Ultraviolet and X-ray properties of Coma's ultra-diffuse galaxies
Gallo, Elena; Hodges-Kluck, Edmund; Lee, Chris H.
Many ultra-diffuse galaxies (UDGs) have been discovered in the Coma cluster, and there is evidence that some, notably Dragonfly 44, have Milky Way-like dynamical masses despite dwarf-like stellar masses. We used X-ray, ultraviolet (UV), and optical data to investigate the star formation and nuclear activity in the Coma UDGs, and we obtained deep U…
Do bulges stop stars forming?
Eales, Stephen; Eales, Oliver; de Vis, Pieter
In this paper, we use the Herschel Reference Survey to make a direct test of the hypothesis that the growth of a stellar bulge leads to a reduction in the star formation efficiency of a galaxy (or conversely a growth in the gas-depletion time-scale) as a result of the stabilization of the gaseous disc by the gravitational field of the bulge. We fi…
The nature of the symbiotic candidate 2MASS J07363415+6538548 in the field of NGC 2403
Merc, J.; Gális, R.; Wolf, M. +2 more
New Online Database of Symbiotic Variables includes several poorly characterized objects and candidate symbiotic stars, not only in the Milky Way but also in other galaxies. The goal of the research presented in this paper was to reveal the nature of 2MASS J07363415+6538548, the object discovered as an X-ray source in the field of NGC 2403, and te…
Determining the origin of the building blocks of the Ice Giants based on analogue measurements from comets
Mousis, O.; Mandt, K. E.; Treat, S.
The abundances of the heavy elements and isotopic ratios in the present atmospheres of the giant planets can be used to trace the composition of volatiles that were present in the icy solid material that contributed to their formation. The first definitive measurements of noble gas abundances and isotope ratios at comet 67P/Churyumov-Gerasimenko (…
K2-HERMES II. Planet-candidate properties from K2 Campaigns 1-13
Kane, Stephen R.; Casey, Andrew R.; Wittenmyer, Robert A. +22 more
Accurate and precise radius estimates of transiting exoplanets are critical for understanding their compositions and formation mechanisms. To know the planet, we must know the host star in as much detail as possible. We present complete results for planet-candidate hosts from the K2-HERMES survey, which uses the HERMES multi-object spectrograph on…
Distorted surfaces of magnetic helium-peculiar stars: an application to a Cen
Niemczura, E.; Leone, F.; Krtička, J. +3 more
Helium-peculiar magnetic chemically peculiar stars show variations of helium abundance across their surfaces. As a result of associated atmospheric scale height variations, the stellar surface becomes distorted, with helium-rich regions dented inwards. Effectively, on top of flux variations due to opacity effects, the depressed helium-rich surface…
Colour-colour and colour-magnitude diagrams for hot Jupiters
Bailey, J.; Melville, G.; Kedziora-Chudczer, L.
We use ground-based and space-based eclipse measurements for the near-infrared (IR) bands (JHKs) and Spitzer 3.6- and 4.5-µm bands to construct colour-colour and colour-magnitude diagrams for hot Jupiters. We compare the results with previous observations of substellar objects and find that hot Jupiters, when corrected for their i…
A new spectroscopic analysis of the massive O + O type binary HD 54662 AB
Maíz Apellániz, J.; Fullerton, A. W.; Barbá, R. H. +9 more
HD 54662 AB is one of the three O + OB binaries known so far with orbital period longer than 1000 d, offering the opportunity to test scenarios of massive star formation and models of single stellar evolution. Here, we present a detailed study of this system based on new high-resolution spectra and data. A disentangling method is used to recover t…