Search Publications
Multiwavelength campaign on the Super-Eddington NLS1 RX J0134.2-4258 - I. Peculiar X-ray spectra and variability
Done, Chris; Ward, Martin; Jin, Chichuan +3 more
We have conducted a new long-term multiwavelength campaign on one of the most super-Eddington narrow-line Seyfert 1s (NLS1s) known, namely RX J0134.2-4258. In this first paper, we report deep simultaneous X-ray observations performed by XMM-Newton and NuSTAR on 2019 December 19, during which RX J0134.2-4258 was fortuitously at one of its lowest X-…
Characteristics of chromospheric oscillation periods in magnetic bright points
Tavabi, Ehsan; Sadeghi, Rayhane
In this investigation, oscillation periods in Mg II k-line intensity, brightness temperature, and Doppler velocity obtained above magnetic bright points (MBPs) are investigated. For this purpose, data from the Interface Region Imaging Spectrometer (IRIS) observing the higher chromosphere and transition region (TR) were analysed, together with imag…
The Influence of Temperature and Photobleaching on Irradiated Sodium Chloride at Europa-like Conditions
Brown, Michael E.; Denman, William T. P.; Trumbo, Samantha K.
Europa's leading-hemisphere chaos regions have a spectral feature at 450 nm that has been attributed to absorption by crystal defects in irradiated sodium chloride, known as F-centers. Some discrepancies exist between the laboratory data of irradiated sodium chloride and the observations, including a ~10 nm shift in central wavelength of the F-cen…
Probing dark gauge boson with observations from neutron stars
Lu, Bo-Qiang; Chiang, Cheng-Wei
We present an investigation on the production of light dark gauge bosons by the nucleon bremsstrahlung processes in the core of neutron stars. The dark vector is assumed to be a U (1 )B-L gauge boson with a mass much below keV. We calculate the emission rate of the dark vector produced by the nucleon bremsstrahlung in the degenerate nuc…
NGC 3147: a prototypical low-luminosity active galactic nucleus with double-peaked optical and ultraviolet lines
Laor, Ari; Bianchi, Stefano; Chiaberge, Marco +3 more
A previous narrow-slit (0.1 arcsec) Hubble Space Telescope observation unveiled a broad relativistic Hα profile in NGC 3147, a low-luminosity (Lbol ~ 1042 erg s-1), low-Eddington ratio (Lbol/LEdd ~ 10-4) active galactic nucleus (AGN), formerly believed to be a candidate true type 2 …
Extreme Energy Spectra of Relativistic Electron Flux in the Outer Radiation Belt
Artemyev, A. V.; Angelopoulos, V.; Mourenas, D. +1 more
Electron diffusion by whistler-mode chorus waves is one of the key processes controlling the dynamics of relativistic electron fluxes in the Earth's radiation belts. It is responsible for the acceleration of sub-relativistic electrons injected from the plasma sheet to relativistic energies as well as for their precipitation and loss into the atmos…
The nature of the radio source detected towards the exoplanet system 1RXS1609.1-210524
Narang, Mayank
Several studies have been carried out to detect radio emissions from known exoplanets. Some of these studies have resulted in tentative detections of radio sources near the position of known exoplanets. One such planet/brown dwarf around which a radio source was detected is 1RXS1609.1-210524 (hereafter 1RX) b. A radio source near 1RX was detected …
Geology, in-situ resource-identification and engineering analysis of the Vernal crater area (Arabia Terra): A suitable Mars human landing site candidate
Pajola, M.; Cremonese, G.; Thomas, N. +15 more
A multidisciplinary study of an ancient area of Mars (Early to Late Noachian) located in Arabia Terra is presented, centred at 6°1′N, 354°54′ E and including the 55 km size Vernal crater. By means of different spatial scale imagery datasets and digital terrain models (MOLA, THEMIS, HRSC, CTX, CaSSIS and HiRISE), we prepare a high-resolution geolog…
Implications from secondary emission from neutral impact on Cassini plasma and dust measurements
Edberg, N. J. T.; Vigren, E.; Eriksson, A. I. +4 more
We investigate the role of secondary electron and ion emission from impact of gas molecules on the Cassini Langmuir probe (RPWS-LP or LP) measurements in the ionosphere of Saturn. We add a model of the emission currents, based on laboratory measurements and data from comet 1P/Halley, to the equations used to derive plasma parameters from LP bias v…
What are the Composition and Power of the Jet in Cyg X-1?
Zdziarski, Andrzej A.; Egron, Elise
We calculate the electron-positron pair production rate at the base of the jet of Cyg X-1 by collisions of photons from its hot accretion flow using the measurement of its average soft gamma-ray spectra by the Compton Gamma Ray Observatory and INTEGRAL satellites. We have found that this rate approximately equals the flow rate of the leptons emitt…