Search Publications
Kinematic complexity around NGC 419: resolving the proper motion of the cluster, the Small Magellanic Cloud, and the Magellanic bridge
Bellini, Andrea; Libralato, Mattia; Massari, Davide +1 more
We present Hubble Space Telescope proper motions in the direction of the star cluster NGC 419 in the Small Magellanic Cloud. Because of the high precision of our measurements, for the first time it is possible to resolve the complex kinematics of the stellar populations located in the field, even along the tangential direction. In fact, the proper…
Estimating black hole masses in obscured AGN using X-rays
Gliozzi, Mario; Williams, James K.; Michel, Dina A.
Determining the black hole masses in active galactic nuclei (AGN) is of crucial importance to constrain the basic characteristics of their central engines and shed light on their growth and co-evolution with their host galaxies. While the black hole mass (MBH) can be robustly measured with dynamical methods in bright type 1 AGN, where t…
Narrow belt of debris around the Sco-Cen star HD 141011
Pinte, C.; Milli, J.; Menard, F. +22 more
Context. We initiated a deep-imaging survey of Scorpius-Centaurus A-F stars in 2015. These stars are predicted to host warm inner and cold outer belts of debris reminiscent of the architecture of emblematic systems such as HR 8799.
Aims: We present resolved images of a ring of debris around the F5-type star HD 141011 that was observed as part…
Energetic Charged Particles in the Terrestrial Magnetosphere: Cluster/RAPID Results
Daly, P. W.; Klecker, B.; Malykhin, A. Yu. +3 more
In this work, we review the results of observations by the Cluster/Research with Adaptive Particle Imaging Detectors (RAPID) energetic charged particle detector (∼>40 keV-∼1 MeV). The origin of energetic ions in the region upstream of the Earth's bow shock is compared under different solar wind conditions. We give a brief overview of the accele…
Multi-wavelength analysis of CME-driven shock and Type II solar radio burst band-splitting
Ebenezer, E.; Lata Soni, Shirsh; lal Yadav, Manohar
It is now well established that Coronal Mass Ejections (CMEs) may produce shocks in near Sun and interplanetary medium. A Type-II radio burst is characterized by shock and associated emission with very slow frequency drift rate (∼0.1 MHz/sec). A CME driven shock and their velocity, acceleration/deceleration signature can be observed by a Type-II s…
The initial properties of young star clusters in M83
Sills, Alison; Webb, Jeremy J.
The initial sizes and masses of massive star clusters provide information about the cluster formation process and also determine how cluster populations are modified and destroyed, which have implications for using clusters as tracers of galaxy assembly. Young massive cluster populations are often assumed to be unchanged since cluster formation; t…
Fundamental parameters of the Ap-stars GO And, 84 UMa, and κ Psc
Sitnova, T. M.; Romanovskaya, A. M.; Ryabchikova, T. A. +1 more
Aims: The aim of this work is to determine fundamental parameters of three Ap stars, GO And (HD 4778), κ Psc (HD 220825), and 84 UMa (HD 120198), using spectroscopic techniques. By analysing these stars, we complete the sample of Ap stars for which fundamental parameters have additionally been derived by means of interferometry. This enables …
A nonlinear solar magnetic field calibration method for the filter-based magnetograph by the residual network
Ji, Kaifan; Su, Jiangtao; Deng, Yuanyong +6 more
Context. The method of solar magnetic field calibration for the filter-based magnetograph is normally the linear calibration method under weak-field approximation that cannot generate the strong magnetic field region well due to the magnetic saturation effect.
Aims: We try to provide a new method to carry out the nonlinear magnetic calibratio…
Subion-Scale Flux Rope Nested Inside Ion-Scale Flux Rope in Earth's Magnetotail
Wang, Z.; Liu, Y. Y.; Fu, H. S. +2 more
Magnetic flux ropes (MFRs)—transient magnetic structures widely observed in Earth's magnetosphere—play crucial roles in particle acceleration and energy dissipation. MFRs above ion scale have been well studied, while MFRs at subion scales and their coupling with larger-scale ropes still remains not well understood. In this paper, we present the fi…
Fe XVII 2p-3s Line Ratio Diagnostic of Shock Formation Radius in O Stars
Leutenegger, Maurice A.; Grell, Gabriel J.; Shah, Chintan
The 2p-3s lines of Fe XVII in the X-ray spectrum of the O-type star ζ Puppis exhibit an anomalous (3G + M2)/(3F) line ratio of ~1.4, in comparison with ~2.4 for almost all other collisionally excited astrophysical spectra. Based on the work of Mauche et al., we conjectured that the strong UV field of ζ Puppis produces the observed ratio by depopul…