Search Publications
Ionizing stellar population in the disc of NGC 3310 - II. The Wolf-Rayet population
Pérez-Montero, E.; Sánchez, S. F.; Díaz, A. I. +3 more
We use integral field spectroscopy to study in detail the Wolf-Rayet (WR) population in NGC 3310, spatially resolving 18 star-forming knots with typical sizes of 200-300 pc in the disc of the galaxy hosting a substantial population of WRs. The detected emission in the so-called blue bump is attributed mainly to late-type nitrogen WRs (WNL), rangin…
Validation of optimized population synthesis through mock spectra and Galactic globular clusters
Schiavon, Ricardo P.; Courteau, Stéphane; Roediger, Joel C. +1 more
Optimized population synthesis provides an empirical method to extract the relative mix of stellar evolutionary stages and the distribution of atmospheric parameters within unresolved stellar systems, yet a robust validation of this method is still lacking. We here provide a calibration of population synthesis via non-linear bound-constrained opti…
Molecular line mapping of the giant molecular cloud associated with RCW 106 - IV. Ammonia towards dust emission
Hill, T.; Marshall, J. P.; Urquhart, J. S. +7 more
Here we report observations of the two lowest inversion transitions of ammonia (NH3) with the 70-m Tidbinbilla radio telescope. The aim of the observations is to determine the kinetic temperatures in the dense clumps of the G333 giant molecular cloud associated with RCW 106 and to examine the effect that accurate measures of temperature…
A refined classification of SPEs based on the multienergy channel observations
Cho, K. -S.; Kim, R. -S.; Park, Y. -D. +2 more
We have investigated characteristics of solar proton events (SPEs) and their association with other types of solar eruption using 42 SPEs observed with SOlar and Heliospheric Observatory/Energetic and Relativistic Nuclei and Electron detector from 1997 to 2012. A velocity dispersion analysis was performed to correctly estimate the onset times of p…
An unusual long-lived relativistic electron enhancement event excited by sequential CMEs
Yang, Xiao C.; Zhu, Guang W.; Zhang, Xiao X. +3 more
An unusual long-lived intense relativistic electron enhancement event from July to August 2004 is examined using data from Fengyun-1, POES, GOES, ACE, the Cluster Mission, and geomagnetic indices. During the initial 6 days of this event, the observed fluxes in the outer zone enhanced continuously, and their maximum increased from 2.1 × 102
The atypical generation mechanism of Titan's Schumann resonance
Béghin, Christian
The observation of a presumed Schumann resonance (SR) during the landing of the Huygens Probe in Titan's atmosphere on January 2005 was subsequently reported and interpreted by Béghin et al. (2007, 2009, 2010, 2012) as being generated through the interaction of Saturn's magnetosphere with Titan's ionosphere rather than from the lightning activity …
The local ISM in three dimensions: kinematics, morphology and physical properties
Redfield, Seth; Linsky, Jeffrey L.
We summarize the results of our long-term program to study the kinematics, morphology, and physical properties of warm partially ionized interstellar gas located within 100 pc of the Sun. Using the Space Telescope Imaging Spectrograph (STIS) and other spectrographs on the Hubble Space Telescope (HST), we measure radial velocities of neutral and si…
Rotational/compressional nature of the magnetopause: Application of the BV technique on a magnetopause case study
Dorville, Nicolas; Belmont, Gérard; Rezeau, Laurence +2 more
The magnetopause boundary implies two main kinds of variations: a density/temperature gradient and a magnetic field rotation. Other variations are associated with these two, concerning in particular the flow velocity, the electric field, and the plasma composition. Compressional and rotational variations are always observed in a close vicinity of …
Verification of the Helioseismology Travel-time Measurement Technique and the Inversion Procedure for Sound Speed Using Artificial Data
Kosovichev, A. G.; Parchevsky, K. V.; Zhao, J. +1 more
We performed three-dimensional numerical simulations of the solar surface acoustic wave field for the quiet Sun and for three models with different localized sound-speed perturbations in the interior with deep, shallow, and two-layer structures. We used the simulated data generated by two solar acoustics codes that employ the same standard solar m…
Magnetic pileup boundary and field draping at Comet Halley
Volwerk, M.; Bertucci, C.; Delva, M. +2 more
The approach of the Rosetta S/C to Comet Churyumov-Gerasimenko in 2014 reactivates the interest in the plasma interaction of the solar wind with the cometary coma. In preparation for the upcoming S/C observations and the start of outgassing of the cometary nucleus, we reinvestigate the magnetic field data from the Vega-1 S/C at the flyby of Comet …