Search Publications
Observation of bi-directional jets in a prominence
Polito, V.; Hillier, A.
Quiescent prominences host a large range of flows, many driven by buoyancy, which lead to velocity shear. The presence of these shear flows could bend and stretch the magnetic field resulting in the formation of current sheets which can lead to magnetic reconnection. Though this has been hypothesised to occur in prominences, with some observations…
Low surface brightness galaxies in z > 1 galaxy clusters: HST approaching the progenitors of local ultra diffuse galaxies
Muzzin, Adam; Brammer, Gabriel; van der Burg, Remco F. J. +2 more
Ultra diffuse galaxies (UDGs) are a type of large low surface brightness (LSB) galaxies with particularly large effective radii (reff > 1.5 kpc) that are now routinely studied in the Local (z < 0.1) Universe. While they are found to be abundant in clusters, groups, and in the field, their formation mechanisms remain elusive and co…
Photospheric downflows observed with SDO/HMI, HINODE, and an MHD simulation
Malherbe, J. M.; Roudier, T.; Ballot, J. +3 more
Downflows on the solar surface are suspected to play a major role in the dynamics of the convection zone, at least in its outer part. We investigate the existence of the long-lasting downflows whose effects influence the interior of the Sun but also the outer layers. We study the sets of Dopplergrams and magnetograms observed with Solar Dynamics O…
Variable oxygen emission from the accretion disk of Mrk 110
Grosso, N.; Porquet, D.; Reeves, J. N. +2 more
Six XMM-Newton observations of the bright narrow line Seyfert 1, Mrk 110, from 2004-2020, are presented. The analysis of the grating spectra from the Reflection Grating Spectrometer (RGS) reveals a broad component of the He-like Oxygen (O VII) line, with a full width at half maximum of 15 900 ± 1800 km s−1 measured in the mean spectrum.…
A deep XMM-Newton observation of the X-Persei-like binary system CXOU J225355.1+624336
Sidoli, L.; Esposito, P.; La Palombara, N. +2 more
We report on the follow-up XMM-Newton observation of the persistent X-ray pulsar CXOU J225355.1+624336, which was discovered with the CATS@BAR project on archival Chandra data. The source was detected at fX(0.5−10 keV) = 3.4 × 10−12 erg cm−2 s−1, a flux level that is fully consistent with previous observ…
The host galaxy of the short GRB 050709
Magnelli, B.; Palazzi, E.; Greiner, J. +10 more
The host of the short gamma-ray burst (GRB) 050709 is a morphologically disturbed low-luminous galaxy. At a redshift of z = 0.16, it belongs to one of the cosmologically nearest short-GRB hosts identified to date. Consequently, it represents a promising target for sensitive, spatially resolved observational studies. We have used the Multi Unit Spe…
The Gaia RVS benchmark stars. I. Chemical inventory of the first sample of evolved stars and its Rb NLTE investigation
Steffen, M.; Ludwig, H. -G.; Bonifacio, P. +21 more
Context. The Radial Velocity Spectrometer (RVS) on board the Gaia satellite is not provided with a wavelength calibration lamp. It uses its observations of stars with known radial velocity to derive the dispersion relation. To derive an accurate radial velocity calibration, a precise knowledge of the line spread function (LSF) of the RVS is necess…
The orbits of Triton and Nereid and the pole orientation of Neptune from Voyager, Hubble Space Telescope, and Earth-based astrometry in 1847-2020
Fu, Yanning; Yuan, Ye; Chen, Jian +1 more
Context. New observations and new planetary and satellite ephemerides provide opportunities to improve the ephemerides for Triton and Nereid as well as relevant parameters. In particular, the observations include a lot of new accurate Earth-based positions reduced with Gaia astrometic catalogs and accurate positions obtained from Hubble Space Tele…
The contribution by luminous blue variable stars to the dust content of the Magellanic Clouds
Asmus, D.; Mehner, A.; de Wit, W. -J. +6 more
Context. Previous studies have concluded that low- and intermediate-mass stars cannot account for the interstellar dust yield in the Magellanic Clouds inferred from far-infrared and sub-millimetre observations.
Aims: Luminous blue variable stars (LBVs) form dust as a result of episodic, violent mass loss. To investigate their contribution as …
Detection of coherent low-frequency radio bursts from weak-line T Tauri stars
Feeney-Johansson, A.; Purser, S. J. D.; Ray, T. P. +7 more
In recent years, thanks to new facilities such as LOFAR that are capable of sensitive observations, much work has been done on the detection of stellar radio emission at low frequencies. Such emission has commonly been shown to be coherent emission, generally attributed to electron-cyclotron maser (ECM) emission, and has usually been detected from…