Search Publications
Fast Bayesian inference for slow-roll inflation
Ringeval, Christophe
We present and discuss a new approach increasing by orders of magnitude the speed of performing Bayesian inference and parameter estimation within the framework of slow-roll inflation. The method relies on the determination of an effective likelihood for inflation which is a function of the primordial amplitude of the scalar perturbations compleme…
The case against large intensity fluctuations in the z ∼ 2.5 He II Lyα forest
McQuinn, Matthew; Worseck, Gabor
Previous studies of the 2.2 < z < 2.7 He II Lyα forest measured much larger ionizing background fluctuations than are anticipated theoretically. We re-analyse recent Hubble Space Telescope data from the two He II sightlines that have been used to make these measurements, HE 2347-4342 and HS 1700+6416, and find that the vast majority of the a…
The average 0.5-200 keV spectrum of local active galactic nuclei and a new determination of the 2-10 keV luminosity function at z ≈ 0
Ballantyne, D. R.
The broad-band X-ray spectra of active galactic nuclei (AGNs) contains information about the nuclear environment from Schwarzschild radii scales (where the primary power law is generated in a corona) to distances of ∼1 pc (where the distant reflector may be located). In addition, the average shape of the X-ray spectrum is an important input into X…
Comparing supernova remnants around strongly magnetized and canonical pulsars
Rea, N.; Torres, D. F.; Martin, J. +1 more
The origin of the strong magnetic fields measured in magnetars is one of the main uncertainties in the neutron star field. On the other hand, the recent discovery of a large number of such strongly magnetized neutron stars is calling for more investigation on their formation. The first proposed model for the formation of such strong magnetic field…
Discovery of the Fomalhaut C debris disc
Duchêne, G.; Lestrade, J. -F.; Wyatt, M. C. +5 more
Fomalhaut is one of the most interesting and well-studied nearby stars, hosting at least one planet, a spectacular debris ring and two distant low-mass stellar companions (TW PsA and LP 876-10, a.k.a. Fomalhaut B and C). We observed both companions with Herschel, and while no disc was detected around the secondary, TW PsA, we have discovered the s…
Infrared properties of blazars: putting the GASP-WEBT sources into context
Villata, M.; Carnerero, M. I.; Raiteri, C. M. +16 more
The infrared properties of blazars can be studied from the statistical point of view with the help of sky surveys, like that provided by the Wide-field Infrared Survey Explorer and the Two Micron All Sky Survey. However, these sources are known for their strong and unpredictable variability, which can be monitored for a handful of objects only. In…
Herschel observations of debris discs orbiting planet-hosting subgiants
Wyatt, Mark C.; Johnson, John A.; Kennedy, Grant M. +2 more
Debris discs are commonly detected orbiting main-sequence stars, yet little is known regarding their fate as the star evolves to become a giant. Recent observations of radial velocity detected planets orbiting giant stars highlight this population and its importance for probing, for example, the population of planetary systems orbiting intermediat…
Heavy metals in a light white dwarf: abundances of the metal-rich, extremely low-mass GALEX J1717+6757
Hermes, J. J.; Gänsicke, B. T.; Dhillon, V. S. +9 more
Using the Hubble Space Telescope, we detail the first abundance analysis enabled by far-ultraviolet spectroscopy of a low-mass (≃0.19 M⊙) white dwarf (WD), GALEX J1717+6757, which is in a 5.9-h binary with a fainter, more-massive companion. We see absorption from nine metals, including roughly solar abundances of Ca, Fe, Ti, and P. We d…
Probing the circumnuclear stellar populations of starburst galaxies in the near-infrared
Pastoriza, M. G.; Hernandez-Jimenez, J. A.; Riffel, R. +3 more
We employ the NASA Infrared Telescope Facility's near-infrared spectrograph SpeX at 0.8-2.4 µm to investigate the spatial distribution of the stellar populations (SPs) in the four well-known starburst galaxies: NGC 34, NGC 1614, NGC 3310 and NGC 7714. We use the STARLIGHT code updated with the synthetic simple SPs models computed by Maraston…
Herschel SPIRE and PACS observations of the red supergiant VY CMa: analysis of the molecular line spectra
Blommaert, J. A. D. L.; Matsuura, Mikako; Barlow, M. J. +10 more
We present an analysis of the far-infrared and submillimetre molecular emission-line spectrum of the luminous M-supergiant VY CMa, observed with the Spectral and Photometric Imaging Receiver (SPIRE) and Photodetector Array Camera and Spectrometer for Herschel spectrometers aboard the Herschel Space Observatory. Over 260 emission lines were detecte…