Search Publications
On significance of VLBI/Gaia position offsets
Petrov, L.; Kovalev, Y. Y.
We have cross matched the Gaia Data Release 1 secondary data set that contains positions of 1.14 billion objects against the most complete to date catalogue of very long baseline interferometry (VLBI) positions of 11.4 thousand sources, almost exclusively active galactic nuclei. We found 6064 matches, I.e. 53 per cent radio objects. The median unc…
Observational Signatures of Transverse Magnetohydrodynamic Waves and Associated Dynamic Instabilities in Coronal Flux Tubes
Yokoyama, T.; Antolin, P.; De Moortel, I. +1 more
Magnetohydrodynamic (MHD) waves permeate the solar atmosphere and constitute potential coronal heating agents. Yet, the waves detected so far may be but a small subset of the true existing wave power. Detection is limited by instrumental constraints but also by wave processes that localize the wave power in undetectable spatial scales. In this stu…
How Do Stars Gain Their Mass? A JCMT/SCUBA-2 Transient Survey of Protostars in Nearby Star-forming Regions
Herczeg, Gregory J.; Kwon, Woojin; Soam, Archana +55 more
Most protostars have luminosities that are fainter than expected from steady accretion over the protostellar lifetime. The solution to this problem may lie in episodic mass accretion—prolonged periods of very low accretion punctuated by short bursts of rapid accretion. However, the timescale and amplitude for variability at the protostellar phase …
The Geometry of the Sagittarius Stream from Pan-STARRS1 3π RR Lyrae
Chambers, Kenneth C.; Rix, Hans-Walter; Belokurov, Vasily +11 more
We present a comprehensive and precise description of the Sagittarius (Sgr) stellar stream’s 3D geometry as traced by its old stellar population. This analysis draws on the sample of ∼44,000 RR Lyrae (RRab) stars from the Pan-STARRS1 (PS1) 3π survey, which is ∼ 80 % complete and ∼ 90 % pure within 80 kpc, and extends to ≳ 120 {kpc} with a distance…
Outflows, infall and evolution of a sample of embedded low-mass protostars. The William Herschel Line Legacy (WILL) survey
André, Ph.; Könyves, V.; Fedele, D. +22 more
Context. Herschel observations of water and highly excited CO (J > 9) have allowed the physical and chemical conditions in the more active parts of protostellar outflows to be quantified in detail for the first time. However, to date, the studied samples of Class 0/I protostars in nearby star-forming regions have been selected from bright, well…
Kinematics of the local disk from the RAVE survey and the Gaia first data release
Robin, Annie C.; Bienaymé, Olivier; Fernández-Trincado, José G. +1 more
Aims: We attempt to constrain the kinematics of the thin and thick disks using the Besançon population synthesis model together with RAVE DR4 and Gaia first data release (TGAS).
Methods: The RAVE fields were simulated by applying a detailed target selection function and the kinematics was computed using velocity ellipsoids depending on a…
K2-106, a system containing a metal-rich planet and a planet of lower density
Deeg, H.; Erikson, A.; Fridlund, M. +43 more
Aims: Planets in the mass range from 2 to 15 M⊕ are very diverse. Some of them have low densities, while others are very dense. By measuring the masses and radii, the mean densities, structure, and composition of the planets are constrained. These parameters also give us important information about their formation and evolution, an…
The formation of the Milky Way halo and its dwarf satellites; a NLTE-1D abundance analysis. I. Homogeneous set of atmospheric parameters
Jablonka, P.; North, P.; Sitnova, T. +2 more
We present a homogeneous set of accurate atmospheric parameters for a complete sample of very and extremely metal-poor stars in the dwarf spheroidal galaxies (dSphs) Sculptor, Ursa Minor, Sextans, Fornax, Boötes I, Ursa Major II, and Leo IV. We also deliver a Milky Way (MW) comparison sample of giant stars covering the - 4 < [Fe/H] < - 1.7 m…
SHARP - IV. An apparent flux-ratio anomaly resolved by the edge-on disc in B0712+472
Vegetti, S.; McKean, J. P.; Auger, M. W. +6 more
Flux-ratio anomalies in quasar lenses can be attributed to dark matter substructure surrounding the lensing galaxy and thus used to constrain the substructure mass fraction. Previous applications of this approach infer a substructure abundance that is potentially in tension with the predictions of Λ cold dark matter cosmology. However, the assumpt…
Dominant dark matter and a counter-rotating disc: MUSE view of the low-luminosity S0 galaxy NGC 5102
Cappellari, Michele; Walcher, C. Jakob; Mitzkus, Martin
The kinematics and stellar populations of the low-mass nearby S0 galaxy NGC 5102 are studied from integral field spectra taken with the Multi-Unit Spectroscopic Explorer. The kinematic maps reveal for the first time that NGC 5102 has the characteristic 2σ peaks indicative of galaxies with counter-rotating discs. This interpretation is quantitative…