EDP Sciences

Vol. 621
In section 6. Interstellar and circumstellar matter

Particle transport within the pulsar wind nebula HESS J1825-137

by H.E.S.S. Collaboration 2019, A&A, 621, A116 alt

This is a detailed dissection of a supernova remnant-pulsar wind nebula association with energies extending to above 10 TeV. The structure of the nebula is completely resolved in all energy bands, the extent of the energy dependence becoming a test of the diffusion mechanism for propagation of high energy particles in this moderately young system.

Vol. 621
In section 6. Interstellar and circumstellar matter

Characterizing young protostellar disks with the CALYPSO IRAM-PdBI survey: large Class 0 disks are rare

by A. Maury, Ph. André, L. Testi, et al. 2019, A&A, 621, A76 alt

The earliest phases of protoplanetary disk evolution are still poorly understood, and investigating them requires sub-arcsecond resolution observations. This paper presents the results of 1.3 and 3 mm-wavelength continuum observations of a sample of 16 Class 0 protostars in the framework of the Continuum And Lines in Young ProtoStellar Objects (CALYPSO) survey, carried out using the IRAM PdBI. By modeling the observed visibilities with an envelope and a Gaussian disk-like component, the authors conclude that while most Class 0 protostars show evidence of embedded disks, only 4 out of the 16 protostars are likely to harbor large (> 60au) protostellar disks. This higher occurrence of small disks in the youngest protostars favors magnetized models of rotating protostellar collapse, since the magnetic fields can reduce the envelope rotation and delay the formation of large disks.

Vol. 621
In section 7. Stellar structure and evolution

Searching for the most powerful thermonuclear X-ray bursts with the Neil Gehrels Swift Observatory

by J.J.M. in 't Zand, M.J.W. Kries, D.M. Palmer, and N. Degenaar, 2019, A&A, 621, A53


Type I bursts occur onto the surface of a neutron star when the infalling matter from the companion star piles up, increases the overall pressure and temperature, and then suddenly undergoes a thermonuclear flash. In this paper, in ’t Zand and collaborators carry out a comprehensive search for type I bursts in accreting neutron stars in our Galaxy over 13 years observations from the Neil Gehrels Swift Observatory. They find more than 100 bursts. Particularly interesting is the dozen intermediate-duration bursts that show strong dipping activity. These fluctuations should stem for a resettling accretion disc that was disrupted by the burst of radiation.

Vol. 621
In section 3. Cosmology

Hydrostatic mass profiles in X-COP galaxy clusters

by S. Ettori et al. 2019, A&A, 621, A39


Non-thermal pressure support in X-COP galaxy clusters

by S. Eckert et al. 2019, A&A, 621, A40

Universal thermodynamic properties of the intracluster medium over two decades in radius in the X-COP sample

by S. Ghirardini et al. 2019, A&A, 621, A41 alt

The series of three XMM Cluster Outskirts Project (X-COP) articles published by the A&A journal presents a complete current view of 12 nearby massive galaxy clusters from a joint X-ray and SZ analysis with XMM-Newton and Planck data. The papers detail the clusters' baryonic content, pressure, and thermodynamic profiles out to large radii. This work probes the dark-matter distribution and provides an important addition to the ongoing "hydrostatic mass bias" discussion for galaxy clusters.

Vol. 621
In section 9. The Sun

Spiral-shaped wavefronts in a sunspot umbra

by T. Felipe, C. Kuckein, E. Khomenko, and I. Thaler, 2019, A&A 621, A43


Sunspots are large concentrations of magnetic field at the surface of the Sun. In this paper, the authors identify a two-armed spiral wavefront in a sunspot through the analysis of the (vertical) Doppler motions. These can be interpreted as the signature of magneto-acoustic waves propagating upward along the magnetic field. As such, they might provide new insight into how sunspots are anchored inside the Sun.