Search Publications
Multifrequency polarimetry of a complete sample of PACO radio sources
Ricci, R.; Bonaldi, A.; Bonavera, L. +16 more
We present high-sensitivity polarimetric observations (σP ≃0.6 mJy) in six bands covering the 5.5-38 GHz range of a complete sample of 53 compact extragalactic radio sources brighter than 200 mJy at 20 GHz. The observations, carried out with the Australia Telescope Compact Array, achieved a 91 per cent detection rate (at 5σ). Within thi…
NuSTAR and XMM-Newton observations of the Arches cluster in 2015: fading hard X-ray emission from the molecular cloud
Mori, Kaya; Tomsick, John; Poutanen, Juri +6 more
We present results of long Nuclear Spectroscopic Telescope Array (NuSTAR; 200 ks) and XMM-Newton (100 ks) observations of the Arches stellar cluster, a source of bright thermal (kT ∼ 2 keV) X-rays with prominent Fe xxv Kα 6.7 keV line emission and a nearby molecular cloud, characterized by an extended non-thermal hard X-ray continuum and fluoresce…
Statistics of the fractional polarization of extragalactic dusty sources in Planck HFI maps
Bonavera, L.; González-Nuevo, J.; Toffolatti, L. +2 more
We estimate the average fractional polarization at 143, 217 and 353 GHz of a sample of 4697 extragalactic dusty sources by applying stacking technique. The sample is selected from the second version of the Planck Catalogue of Compact Sources at 857 GHz, avoiding the region inside the Planck Galactic mask (fsky ∼ 60 per cent). We recover…
A test for skewed distributions of dark matter, and a possible detection in galaxy cluster Abell 3827
Massey, Richard; Taylor, Peter; Jauzac, Mathilde +4 more
Simulations of self-interacting dark matter predict that dark matter should lag behind galaxies during a collision. If the interaction is mediated by a high-mass force carrier, the distribution of dark matter can also develop asymmetric dark matter tails. To search for this asymmetry, we compute the gravitational lensing properties of a mass distr…
Late-time VLA reobservations rule out ULIRG-like host galaxies for most pre- Swift long-duration gamma-ray bursts
Hjorth, Jens; Perley, Daniel A.; Tanvir, Nial R. +1 more
We present new Jansky Very Large Array observations of five pre-Swift gamma-ray bursts for which an ultraluminous [star formation rate (SFR) >100 M⊙ yr-1] dusty host galaxy had previously been inferred from radio or submillimetre observations taken within a few years after the burst. In four of the five cases, we no longer…
Metallicity calibrations for dwarf stars and giants in the Geneva photometric system
Netopil, Martin
We use the most homogeneous Geneva seven-colour photometric system to derive new metallicity calibrations for early A- to K-type stars that cover both, dwarf stars and giants. The calibrations are based on several spectroscopic data sets that were merged to a common scale, and we applied them to open cluster data to obtain an additional proof of t…
Testing cosmic acceleration for w(z) parametrizations using fgas measurements in galaxy clusters
Foëx, G.; Motta, V.; Magaña, Juan +1 more
In this paper, we study the cosmic acceleration for five dynamical dark energy models whose equation of state varies with redshift. The cosmological parameters of these models are constrained by performing a Markov chain Monte Carlo (MCMC) analysis using mainly gas mass fraction, fgas, measurements in two samples of galaxy clusters: one…
The footprint of cometary dust analogues - I. Laboratory experiments of low-velocity impacts and comparison with Rosetta data
Blum, J.; Gundlach, B.; Dominik, C. +8 more
Cometary dust provides a unique window on dust growth mechanisms during the onset of planet formation. Measurements by the Rosetta spacecraft show that the dust in the coma of comet 67P/Churyumov-Gerasimenko has a granular structure at size scales from sub-µmup to several hundreds of µm, indicating hierarchical growth took place across…
A halo substructure in Gaia Data Release 1
Myeong, G. C.; Evans, N. W.; Belokurov, V. +2 more
We identify a halo substructure in the Tycho Gaia Astrometric Solution (TGAS) data set, cross-matched with the Radial Velocity Experiment (RAVE-on) data release. After quality cuts, the stars with large radial action (JR > 800 km s-1 kpc) are extracted. A subset of these stars is clustered in longitude and velocity and can…
Detection of two intervening Ne viii absorbers probing warm gas at z ∼ 0.6
Savage, Blair D.; Wakker, Bart P.; Muzahid, Sowgat +3 more
We report on the detection of two Ne viii absorbers, at z = 0.619 07 and 0.570 52 in the Hubble Space Telescope/Cosmic Origins Spectrograph spectrum of background quasars SDSS J080908.13 + 461925.6 and SBS 1122 + 594, respectively. The Ne viii 770 line is at ∼3σ significance. In both instances, the Ne viii is found to be tracing gas with T ≳ 10