Search Publications
Coronal Heating and Solar Wind Formation in Quiet Sun and Coronal Holes: A Unified Scenario
Solanki, Sami K.; Tripathi, Durgesh; Nived, V. N.
Coronal holes (CHs) are darker than the quiet Sun (QS) when observed in coronal channels. This study aims to understand the similarities and differences between CHs and QS in the transition region using the Si IV 1394 Å line, recorded by the Interface Region Imaging Spectrograph, by considering the distribution of magnetic field measured by the He…
Mass-loss law for red giant stars in simple population globular clusters
Milone, A. P.; Cordoni, G.; Marino, A. F. +12 more
The amount of mass lost by stars during the red-giant branch (RGB) phase is one of the main parameters to understand and correctly model the late stages of stellar evolution. Nevertheless, a fully comprehensive knowledge of the RGB mass-loss is still missing. Galactic Globular Clusters (GCs) are ideal targets to derive empirical formulations of ma…
Ultra-compact dwarfs beyond the centre of the Fornax galaxy cluster: hints of UCD formation in low-density environments
Janz, Joachim; Mieske, Steffen; Peletier, Reynier F. +6 more
Ultra-compact dwarf galaxies (UCDs) were serendipitously discovered by spectroscopic surveys in the Fornax cluster 20 yr ago. Nowadays, it is commonly accepted that many bright UCDs are the nuclei of galaxies that have been stripped. However, this conclusion might be driven by biased samples of UCDs in high-density environments, on which most sear…
The Chameleon on the branches: spectral state transition and dips in NGC 247 ULX-1
Fabian, A. C.; Pinto, C.; D'Aì, A. +14 more
Soft Ultra-Luminous X-ray (ULXs) sources are a subclass of the ULXs that can switch from a supersoft spectral state, where most of the luminosity is emitted below 1 keV, to a soft spectral state with significant emission above 1 keV. In a few systems, dips have been observed. The mechanism behind this state transition and the dips nature are still…
High precision meteor observations with the Canadian automated meteor observatory: Data reduction pipeline and application to meteoroid mechanical strength measurements
Weryk, Robert J.; Stober, Gunter; Vida, Denis +3 more
Context. The mirror tracking system of the Canadian Automated Meteor Observatory (CAMO) can track meteors in real time, providing an effective angular resolution of 1 arc second and a temporal resolution of 100 frames per second. Aims. We describe the upgraded hardware and give details of the data calibration and reduction pipeline. We investigate…
Galactic bulge millisecond pulsars shining in x rays: A γ -ray perspective
Calore, Francesca; Petrucci, Pierre-Olivier; Clavel, Maïca +3 more
If the mysterious Fermi-LAT GeV γ -ray excess is due to an unresolved population of millisecond pulsars (MSP) in the Galactic bulge, one expects this very same population to shine in x rays. For the first time, we address the question of what is the sensitivity of current x-ray telescopes to an MSP population in the Galactic bulge. To this end, we…
Origin of metals in old Milky Way halo stars based on GALAH and Gaia
Kobayashi, Chiaki; Tominaga, Nozomu; Nomoto, Ken'ichi +6 more
Stellar and supernova nucleosynthesis in the first few billion years of the cosmic history have set the scene for early structure formation in the Universe, while little is known about their nature. Making use of stellar physical parameters measured by GALAH Data Release 3 with accurate astrometry from the Gaia EDR3, we have selected ~100 old main…
The long period of 3He-rich solar energetic particles measured by Solar Orbiter 2020 November 17-23
Lario, D.; Maksimovic, M.; Vecchio, A. +31 more
We report observations of a relatively long period of 3He-rich solar energetic particles (SEPs) measured by Solar Orbiter. The period consists of several well-resolved ion injections. The high-resolution STEREO-A imaging observations reveal that the injections coincide with extreme ultraviolet jets and brightenings near the east limb, n…
NGTS-14Ab: a Neptune-sized transiting planet in the desert
Bouchy, F.; Erikson, A.; Rauer, H. +35 more
Context. The sub-Jovian, or Neptunian, desert is a previously identified region of parameter space where there is a relative dearth of intermediate-mass planets with short orbital periods.
Aims: We present the discovery of a new transiting planetary system within the Neptunian desert, NGTS-14.
Methods: Transits of NGTS-14Ab were discover…
An Unexpected Whistler Wave Generation Around Dipolarization Front
Wang, Z.; Chen, L.; Zhang, Y. +8 more
Dipolarization front (DF)—a sharp boundary separating hot tenuous plasmas from cold dense plasmas—is followed by a strong Bz region, which is termed flux pileup region (FPR) or dipolarizing flux bundle (DFB). Using 9 year (2001-2009) Cluster data, we show that the FPR hosts whistler waves because of the pancake distribution of electrons…