Search Publications
Predicting gravitational lensing by stellar remnants
Lépine, S.; Harding, Alexander J.; Stefano, R. Di +3 more
Gravitational lensing provides a means to measure mass that does not rely on detecting and analysing light from the lens itself. Compact objects are ideal gravitational lenses, because they have relatively large masses and are dim. In this paper, we describe the prospects for predicting lensing events generated by the local population of compact o…
Registration of H2O and SiO masers in the Calabash Nebula to confirm the planetary nebula paradigm
Kim, J.; Bujarrabal, V.; Dodson, R. +4 more
We report on the astrometric registration of very long baseline interferometry images of the SiO and H2O masers in OH 231.8+4.2, the iconic proto-planetary nebula also known as the Calabash nebula, using the Korean VLBI Network and source frequency phase referencing. This, for the first time, robustly confirms the alignment of the SiO m…
Interpreting the cosmic far-infrared background anisotropies using a gas regulator model
Wu, Hao-Yi; Doré, Olivier; Serra, Paolo +1 more
Cosmic far-infrared background (CFIRB) is a powerful probe of the history of star formation rate (SFR) and the connection between baryons and dark matter across cosmic time. In this work, we explore to which extent the CFIRB anisotropies can be reproduced by a simple physical framework for galaxy evolution, the gas regulator (bathtub) model. This …
X-ray time lags in PG 1211+143
Vaughan, S.; Reeves, J. N.; Pounds, K. +1 more
We investigate the X-ray time lags of a recent ∼630 ks XMM-Newton observation of PG 1211+143. We find well-correlated variations across the XMM-Newton EPIC bandpass, with the first detection of a hard lag in this source with a mean time delay of up to ∼3 ks at the lowest frequencies. We find that the energy-dependence of the low-frequency hard lag…
Characterization of a candidate dual AGN
Torres, M. A. P.; Heida, M.; Jonker, P. G. +2 more
We present Chandra and optical observations of a candidate dual active galactic nucleus (AGN) discovered serendipitously while searching for recoiling black holes via a cross-correlation between the serendipitous XMM source catalogue (2XMMi) and SDSS-DR7 galaxies with a separation no larger than 10 times the sum of their Petrosian radii. The syste…
Extreme star formation in the Milky Way: luminosity distributions of young stellar objects in W49A and W51
König, C.; Moore, T. J. T.; Elia, D. +8 more
We have compared the star-formation properties of the W49A and W51 regions by using far-infrared data from the Herschel infrared Galactic Plane Survey (Hi-GAL) and 850-µm observations from the James Clerk Maxwell Telescope (JCMT) to obtain luminosities and masses, respectively, of associated compact sources. The former are infrared luminosit…
Probing black hole accretion in quasar pairs at high redshift
Vignali, C.; Gilli, R.; Piconcelli, E. +6 more
Models and observations suggest that luminous quasar activity is triggered by mergers, so it should preferentially occur in the most massive primordial dark matter haloes, where the frequency of mergers is expected to be the highest. Since the importance of galaxy mergers increases with redshift, we identify the high-redshift Universe as the ideal…
VALES - IV. Exploring the transition of star formation efficiencies between normal and starburst galaxies using APEX/SEPIA Band-5 and ALMA at low redshift
Leiton, R.; Ibar, E.; Xue, Y. Q. +12 more
In this work, we present new the Swedish-ESO PI receiver for the Atacama Pathfinder Experiment APEX/SEPIA Band-5 observations targeting the CO (J = 2-1) emission line of 24 Herschel-detected galaxies at z = 0.1-0.2. Combining this sample with our recent new Valparaíso ALMA Line Emission Survey (VALES), we investigate the star formation efficiencie…
Asteroseismology of KIC 7107778: a binary comprising almost identical subgiants
Bi, Shaolan; Li, Yaguang; Corsaro, Enrico +5 more
We analyse an asteroseismic binary system: KIC 7107778, a non-eclipsing, unresolved target, with solar-like oscillations in both components. We used Kepler short cadence time series spanning nearly 2 yr to obtain the power spectrum. Oscillation mode parameters were determined using Bayesian inference and a nested sampling Monte Carlo algorithm wit…
Surface abundance and the hunt for stratification in chemically peculiar hot subdwarfs: PG 0909+276 and UVO 0512-08
Wild, J. F.; Jeffery, C. S.
Edelmann identified two chemically peculiar hot subdwarfs, PG 0909+276 and UVO 0512-08, as having very high overabundances of iron-group elements. We obtained high-resolution ultraviolet spectroscopy in order to measure abundances of species not observable in the optical, and to seek evidence for chemical stratification in the photosphere. Abundan…