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Ultraluminous X-ray sources with flat-topped noise and QPO
Fabrika, Sergei; Atapin, Kirill; Caballero-García, Maria D.
We analysed the X-ray power density spectra of five ultraluminous X-ray sources (ULXs) NGC 5408 X-1, NGC 6946 X-1, M 82 X-1, NGC 1313 X-1, and IC 342 X-1 that are the only ULXs that display both flat-topped noise (FTN) and quasi-periodic oscillations (QPOs). We studied the QPO frequencies, fractional root-mean-square (rms) variability, X-ray lumin…
Particle acceleration in the Herbig-Haro objects HH 80 and HH 81
Carrasco-González, Carlos; Vig, Sarita; González-Martín, Omaira +4 more
We present an analysis of radio (Karl G. Jansky Very Large Array (VLA)), optical (Hubble Space Telescope (HST)), and X-ray (Chandra and XMM-Newton) observations and archival data of the Herbig-Haro objects HH 80 and HH 81 in the context of jet-cloud interactions. Our radio images are the highest angular resolution to date of these objects, allowin…
Three-dimensional Density Structure of a Solar Coronal Streamer Observed by SOHO/LASCO and STEREO/COR2 in Quadrature
Van Doorsselaere, Tom; Zhukov, Andrei N.; Decraemer, Bieke
Helmet streamers are a prominent manifestation of magnetic structures with current sheets in the solar corona. These large-scale structures are regions with high plasma density, overlying active regions and filament channels. We investigate the three-dimensional (3D) structure of a coronal streamer, observed simultaneously by white-light coronagra…
High-Frequency Wave Generation in Magnetotail Reconnection: Nonlinear Harmonics of Upper Hybrid Waves
Graham, Daniel B.; Yoon, Peter H.; Sibeck, David G. +4 more
MMS3 spacecraft passed the vicinity of the electron diffusion region of magnetotail reconnection on 3 July 2017, observing discrepancies between perpendicular electron bulk velocities and E>→×B>→ drift, and agyrotropic electron crescent distributions. Analyzing linear wave dispersions, Burch et al. (2019,
{k}_{\perp }^{-8/3} Spectrum in Kinetic Alfvén Wave Turbulence: Implications for the Solar Wind
David, Vincent; Galtier, Sébastien
The nature of solar wind turbulence at large scale is rather well understood in the theoretical framework of magnetohydrodynamics. The situation is quite different at subproton scales where the magnetic energy spectrum measured by different spacecraft does not fit with the classical turbulence predictions: a power-law index close to -8/3 is genera…
Exploring the Origin of Multiwavelength Activities of High-redshift Flat-spectrum Radio Quasar PKS 1502+106 during 2014-2018
Wang, X. Y.; Gu, Q. S.; Xiong, Ding-Rong +4 more
The origin of the multiband activities (outbursts/flares) of blazars is still a heavily debated topic. Shock and magnetic reconnection have long been considered as possible triggers of the multiband activities. In this paper, we present an exploration of the origin of multiband activities for a high-redshift (z = 1.8385) flat-spectrum radio quasar…
Characterization of the precision premium in astrometry
Lin, F. R.; Peng, Q. Y.; Zheng, Z. J. +1 more
The precision premium, a concept in astrometry that was first presented by Pascu in 1994, initially means that the relative positional measurement of the Galilean satellites of Jupiter will be more accurate when their separations are small. Correspondingly, many observations have been obtained of these Galilean satellites since it was introduced. …
Solar ultraviolet bursts in a coordinated observation of IRIS, Hinode and SDO
Tian, Hui; Samanta, Tanmoy; He, JianSen +3 more
Solar ultraviolet (UV) bursts are small-scale compact brightenings in transition region images. The spectral profiles of transition region lines in these bursts are significantly enhanced and broadened, often with chromospheric absorption lines such as Ni~{\sc{ii}} 1335.203 and 1393.330 Å superimposed. We investigate the properties of several UV b…
Unresolved Binaries and Galactic Clusters’ Mass Estimates
Carraro, Giovanni; Borodina, Olga I.; Seleznev, Anton F. +1 more
Binary stars are present in all stellar systems, yet their role is far from being fully understood. We investigate the effect of unresolved binaries in the derivation of open clusters’ mass by star counts. We start from the luminosity functions of five open clusters: IC 2714, NGC 1912, NGC 2099, NGC 6834, and NGC 7142. Luminosity functions are obt…
NuSTAR Observations of the Supernova Remnant RX J1713.7-3946
Uchiyama, Yasunobu; Tanaka, Takaaki; Aharonian, Felix +4 more
The shock waves of supernova remnants (SNRs) are prominent candidates for the acceleration of the Galactic cosmic rays. SNR RX J1713.7-3946 is one well-studied particle accelerator in our Galaxy because of its strong nonthermal X-ray and gamma-ray radiation. We have performed Nuclear Spectroscopic Telescope Array (3-79 keV) observations of the nor…