Search Publications
Missions
Journals
Publication Years
Extreme adaptive optics astrometry of R136. Searching for high proper motion stars
Vakili, F.; Boccaletti, A.; Langlois, M. +9 more
We compared high-contrast near-infrared images of the core of R136 taken by VLT/SPHERE, in two epochs separated by 3.06 years. For the first time we monitored the dynamics of the detected sources in the core of R136 from a ground-based telescope with adaptive optics. The aim of these observations was to search for High prOper Motion cAndidates (HO…
The Micro-Macro Coupling of Mass-Loading in Symmetric Magnetic Reconnection With Cold Ions
Hesse, Michael; Spinnangr, Susanne F.; Tenfjord, Paul +4 more
We investigate how magnetic reconnection is influenced by an inflow of a dense cold ion population. We compare two 2.5D Particle-In-Cell simulations, one containing the cold population and one without. We find that the cold population influences the reconnection process on both global and kinetic scales, and that the dominant contribution can be e…
Functional Principal Component Analysis of Radio-Optical Reference Frame Tie
Makarov, Valeri V.
The Gaia optical reference frame is intrinsically undefined with respect to global orientation and spin, so it needs to be anchored in the radio-based International Celestial Reference Frame (ICRF) to provide a referenced and quasi-inertial celestial coordinate system. The link between the two fundamental frames is realized through two samples of …
Search for LBVs in the Local Volume galaxies: study of four stars in NGC 4449
Vinokurov, A.; Solovyeva, Y.; Atapin, K. +8 more
We continue to search for LBV stars in galaxies outside the Local Group. In this work, we have investigated four luminous stars in NGC 4449. Multiple spectral observations carried out for J122810.94+440540.6, J122811.70+440550.9, and J122809.72+440514.8 revealed the emission features in their spectra that are characteristic of LBVs. Photometry sho…
Clustering of red and blue galaxies around high-redshift 3C radio sources as seen by the Hubble Space Telescope
Chiaberge, Marco; West, Michael J.; Haas, Martin +5 more
To properly understand the evolution of high-redshift galaxy clusters, both passive and star-forming galaxies have to be considered. Here we study the clustering environment of 21 radio galaxies and quasars at 1 < z < 2.5 from the third Cambridge catalog (3C). We use optical and near-infrared Hubble Space Telescope images with a 2' field-of-…
X-Ray Sources in the 1.75 Ms Ultra Narrow Deep Field Observed by XMM-Newton
Vignali, C.; Nicastro, F.; Krongold, Y. +5 more
In this work, we present the results of the survey carried out on one of the deepest X-ray fields observed by the XMM-Newton satellite. The 1.75 Ms Ultra Narrow Deep Field (XMM175UNDF) survey is made by 13 observations taken over 2 yr with a total exposure time of 1.75 Ms (1.372 Ms after flare-filtered) in a field of 30' × 30' centered around the …
Forbidden atomic oxygen emissions in the Martian dayside upper atmosphere
Bhardwaj, Anil; Jain, Sonal Kumar; Raghuram, Susarla
Recently, Nadir and Occultation for Mars Discovery (NOMAD) ultraviolet and visible spectrometer instrument on board the European Space Agency's ExoMars Trace Gas Orbiter (TGO) simultaneously measured the limb emission intensities for both [OI] 2972 and 5577 Å (green) emissions in the dayside of Martian upper atmosphere. But the atomic oxygen red-d…
Multiscale spectral discrimination of poorly crystalline and intermixed alteration phases using aerial and ground-based ExoMars rover emulator data
Allender, E. J.; Cousins, C. R.; Gunn, M. D. +1 more
A key goal of the ExoMars rover Rosalind Franklin is to analyze accessible hydrated mineral deposits using panoramic multiscale and multispectral imagery. We conducted a multiscale spectroscopic study on hydrothermally-altered basalt-hosted soils in the geothermal area of Námafjall in northern Iceland. Basaltic lavas here that have experienced fir…
Evidence of Solar-cycle-related Structural Changes in the Solar Convection Zone
Basu, Sarbani
While it has been relatively easy to determine solar-cycle related changes in solar dynamics, determining changes in structure in the deeper layers of the Sun has proved to be difficult. By using helioseismic data obtained over two solar cycles, and sacrificing resolution in favor of lower uncertainties, we show that there are significant changes …
Automated Photometry of γ Cassiopeiae: The Last Roundup
Smith, M. A.; Henry, G. W.
γ Cassiopeiae (B0.5IVe) is the noted prototype of a subgroup of classical Be stars exhibiting hard thermal X-ray emission. This paper reports results from a 23 yr optical campaign on this star with an automated photometric telescope (APT). A series of unstable long cycles of length 56-91 days has nearly ceased over the last decade. Also, we revise…