Search Publications
Stringent limits on the magnetic field strength in the disc of TW Hya. ALMA observations of CN polarisation
Testi, L.; Williams, J. P.; Facchini, S. +8 more
Despite their importance in the star formation process, measurements of magnetic field strength in proto-planetary discs remain rare. While linear polarisation of dust and molecular lines can give insight into the magnetic field structure, only observations of the circular polarisation produced by Zeeman splitting provide a direct measurement of m…
H α morphologies of star clusters: a LEGUS study of H II region evolution time-scales and stochasticity in low-mass clusters
Herrero, A.; Cignoni, M.; Calzetti, D. +25 more
The morphology of H II regions around young star clusters provides insight into the time-scales and physical processes that clear a cluster's natal gas. We study ∼700 young clusters (≤10 Myr) in three nearby spiral galaxies (NGC 7793, NGC 4395, and NGC 1313) using Hubble Space Telescope (HST) imaging from LEGUS (Legacy ExtraGalactic Ultraviolet Su…
A Photometric and Spectroscopic Investigation of the DB White Dwarf Population Using SDSS and Gaia Data
Genest-Beaulieu, C.; Bergeron, P.
We present a comprehensive analysis of DB white dwarfs drawn from the Sloan Digital Sky Survey, based on model fits to ugriz photometry and medium-resolution spectroscopy from the Sloan Digital Sky Survey. We also take advantage of the exquisite trigonometric parallax measurements recently obtained by the Gaia mission. Using the so-called photomet…
Quasar and galaxy classification in Gaia Data Release 2
Fouesneau, Morgan; Bailer-Jones, Coryn A. L.; Andrae, Rene
We construct a supervised classifier based on Gaussian Mixture Models to probabilistically classify objects in Gaia data release 2 (GDR2) using only photometric and astrometric data in that release. The model is trained empirically to classify objects into three classes - star, quasar, galaxy - for G ≥ 14.5 mag down to the Gaia magnitude limit of …
Separating extended disc features from the protoplanet in PDS 70 using VLT/SINFONI
Pinte, C.; Quanz, S. P.; Casassus, S. +12 more
Transition discs are prime targets to look for protoplanets and study planet-disc interactions. We present VLT/SINFONI observations of PDS 70, a transition disc with a recently claimed embedded protoplanet. We take advantage of the angular and spectral diversity present in our data for an optimal PSF modelling and subtraction using principal compo…
Spatial segregation of dust grains in transition disks. SPHERE observations of 2MASS J16083070-3828268 and RXJ1852.3-3700
Pinte, C.; Ménard, F.; Dent, W. R. F. +27 more
Context. The mechanisms governing the opening of cavities in transition disks are not fully understood. Several processes have been proposed, but their occurrence rate is still unknown.
Aims: We present spatially resolved observations of two transition disks, and aim at constraining their vertical and radial structure using multiwavelength ob…
Two-Dimensional gcPIC Simulation of Rising-Tone Chorus Waves in a Dipole Magnetic Field
Wang, Xueyi; Wang, Shui; Lu, Quanming +4 more
Rising-tone chorus waves have already been successfully produced in a mirror magnetic field with the use of one- and two-dimensional particle-in-cell (PIC) simulations. However, in reality, the background magnetic field in the inner Earth's magnetosphere is a dipole magnetic field, unlike symmetric mirror fields. In this paper, with the two-dimens…
Partly burnt runaway stellar remnants from peculiar thermonuclear supernovae
Geier, S.; Hermes, J. J.; Gänsicke, B. T. +13 more
We report the discovery of three stars that, along with the prototype LP 40-365, form a distinct class of chemically peculiar runaway stars that are the survivors of thermonuclear explosions. Spectroscopy of the four confirmed LP 40-365 stars finds ONe-dominated atmospheres enriched with remarkably similar amounts of nuclear ashes of partial O- an…
A Radio Source Coincident with the Superluminous Supernova PTF10hgi: Evidence for a Central Engine and an Analog of the Repeating FRB 121102?
Berger, E.; Chatterjee, S.; Cordes, J. M. +9 more
We present the detection of an unresolved radio source coincident with the position of the Type I superluminous supernova (SLSN) PTF10hgi (z = 0.098) about 7.5 yr post-explosion, with a flux density of F ν (6 GHz) ≈ 47.3 µJy and a luminosity of L ν (6 GHz) ≈ 1.1 × 1028 erg s-1 Hz-1. Th…
Energy Range of Electron Rolling Pin Distribution Behind Dipolarization Front
Xu, Y.; Fu, H. S.; Burch, J. L. +4 more
The electron rolling pin distribution, showing electron pitch angles primarily at 0°, 90°, and 180°, has recently been observed behind dipolarization fronts (DFs) and explained using an analytical model. However, the energy range of such distribution has been unknown so far, owing to the low-resolution data in previous spacecraft missions. Here us…