Search Publications
The EUV Reflectance of Mercury's Surface Measured by BepiColombo/PHEBUS
Korablev, O.; Chaufray, J. -Y.; Leblanc, F. +10 more
On 9 and 10 October 2021, Probing the Hermean Exosphere by Ultraviolet Spectroscopy aboard BepiColombo observed the disk-integrated reflected light from the Sun by Mercury in the spectral range 90-160 nm at a phase angle of 70°. These observations are used to derive the EUV reflectance of the surface of Mercury in this wavelength range for the fir…
Revisiting the orbital motion of WR 138
Nazé, Yaël; Gosset, Eric; Rauw, Gregor
The optical spectrum of WR 138 exhibits emission lines typical of a WN6o star and absorption lines from a rapidly-rotating OB star. Using a large set of spectroscopic data, we establish a new orbital solution of the WN6o star based on the radial velocities of highly-ionized nitrogen lines. We show that the WN6o star moves on a 4.3 yr orbit with a …
Recent Progress in Finding Binary Systems with the B[e] Phenomenon
Raj, Ashish; Chojnowski, S. Drew; Manset, Nadine +9 more
This paper describes recent studies of the FS CMa-type objects, a group of stars showing the B[e] phenomenon defined in 2007. The objects exhibit strong emission-line spectra with both permitted and forbidden lines suggesting the presence of a B-type star as well as strong IR excesses due to radiation of circumstellar dust. These properties are ha…
The Hydrostatic Mass of A478: Discrepant Results from Chandra, NuSTAR, and XMM-Newton
Wik, Daniel R.; Schellenberger, Gerrit; Wang, Qian H. S. +3 more
Galaxy clusters are the most recently formed and most massive, gravitationally bound structures in the Universe. The number of galaxy clusters formed is highly dependent on cosmological parameters, such as the dark matter density, σ 8, and Ω m . The number density is a function of the cluster mass, which can be estimated from…
Earth's magnetotail variability during supersubstorms (SSSs): A study on solar wind-magnetosphere-ionosphere coupling
Hajra, Rajkumar; Echer, Ezequiel; Franco, Adriane Marques de Souza +1 more
Supersubstorm (SSS) events are associated with extremely intense westward auroral electrojet currents (the minimum SuperMAG AL or SML < - 2500 nT) resulting from the solar wind-magnetosphere coupling. We present, for the first time, variability of the Earth's magnetotail and coupling from the solar wind to magnetotail, geosynchronous orbit and …
Determination of the Spiral Pattern Speed in the Galaxy from Three Samples of Stars
Bobylev, V. V.; Bajkova, A. T.
We invoke the estimates of the amplitudes of the velocity perturbations $fR$ and $f_{θ}$ caused by the influence of a spiral density wave that have been obtained by us previously from three stellar samples. These include Galactic masers with measured VLBI trigonometric parallaxes and proper motions, OB2 stars, and Cepheids. From these d…
Big flares from small stars: detecting flares from faint low-mass stars with NGTS full-frame images
Jackman, James A. G.; Wheatley, Peter J.; Jenkins, James S. +2 more
High-cadence observations of high-energy stellar flares from cool and ultracool dwarfs are often limited by the faint nature of their host stars. Many low-mass sources cannot be detected in quiescence by photometric surveys, meaning they are not targeted for high-cadence observations. This reduces the chances of detecting the rarest high-energy fl…
Modeling the Radiation Environment of Energetic Particles at Mars Orbit and a First Validation against TGO Measurements
Guo, Jingnan; Liu, Weihao; Semkova, Jordanka +1 more
Sending astronauts to Mars will be a milestone of future deep space exploration activities. However, energetic particle radiation in deep space and in the Mars environment is a major risk to the health of future human explorers. The nominal Martian surface radiation field contains primary Galactic Cosmic Ray (GCR) particles and secondary particles…
Search for AGNs in Dwarf Galaxies in the the M81 Field with INTEGRAL Data
Sazonov, S. Yu.; Karachentsev, I. D.; Mereminskiy, I. A. +1 more
Using long-term INTEGRAL hard X-ray observations, we have put upper limits on the bolometric luminosity ($L_{\textrm{bol}}\lesssim 10^{41}$ erg s${}^{-1}$) of the nuclei of 72 nearby dwarf galaxies located in the M81 field. This has allowed us to constrain the fraction of galaxies in which the central black hole accretes matter at a rate above 0.1…
XMM-Newton observation of the TeV-discovered supernova remnant HESS J1534-571
Santangelo, A.; Pühlhofer, G.; Sasaki, M. +3 more
We report the results obtained from XMM-Newton observations of the TeV-detected supernova remnant (SNR) HESS J1534-571. We focus on the nature of the cosmic-ray particle content in the SNR, which is revealed by its γ-ray emission. No signatures of X-ray synchrotron emission were detected from the SNR. This is consistent with earlier results obtain…