Search Publications
Expectations on mass determination using astrometric microlensing by Gaia
Bastian, U.; Wambsganss, J.; Klüter, J.
Context. Astrometric gravitational microlensing can be used to determine the mass of a single star (the lens) with an accuracy of a few percent. To do so, precise measurements of the angular separations between lens and background star with an accuracy below 1 milli - arcsec at different epochs are needed. Therefore only the most accurate instrume…
Is the gap in the DS Tau disc hiding a planet?
Herczeg, Gregory J.; Long, Feng; Pinte, Christophe +6 more
Recent millimetre-wavelength surveys performed with the Atacama Large Millimeter Array (ALMA) have revealed protoplanetary discs characterized by rings and gaps. A possible explanation for the origin of such rings is the tidal interaction with an unseen planetary companion. The protoplanetary disc around DS Tau shows a wide gap in the ALMA observa…
Mawrth Vallis, Mars: A Fascinating Place for Future In Situ Exploration
Horgan, Briony; Poulet, François; Carter, John +4 more
After the successful landing of the Mars Science Laboratory rover, both NASA and ESA initiated a selection process for potential landing sites for the Mars2020 and ExoMars missions, respectively. Two ellipses located in the Mawrth Vallis region were proposed and evaluated during a series of meetings (three for Mars2020 mission and five for ExoMars…
A Ringed Pole-on Outflow from DO Tauri Revealed by ALMA
Zapata, Luis A.; Rodríguez, Luis F.; Guzmán, Andrés E. +3 more
We present new Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 observations including the CO(2-1) line and 1.3 mm continuum emission from the surroundings of the young stellar object DO Tauri. The ALMA CO molecular data show three different series of rings at different radial velocities. These rings have radii around 220 and 800 au. We …
Interaction of electron acoustic waves in the presence of superthermal electrons in terrestrial magnetosphere
Masood, W.; Jahangir, R.
We have investigated the propagation and interaction of nonlinear electron acoustic waves (EAWs) in a plasma comprising hot (superthermal) and cold electrons and immobile ions. We have derived the Korteweg-de Vries equation for EAWs in the small amplitude limit. Employing the Hirota's Direct method, we have investigated the multisoliton solutions …
Cometary Comae-Surface Links
Skorov, Yuri; Kappel, David; Vincent, Jean-Baptiste +9 more
A comet is a highly dynamic object, undergoing a permanent state of change. These changes have to be carefully classified and considered according to their intrinsic temporal and spatial scales. The Rosetta mission has, through its contiguous in-situ and remote sensing coverage of comet 67P/Churyumov-Gerasimenko (hereafter 67P) over the time span …
A Broadband X-Ray Study of a Sample of AGNs with [O III] Measured Inclinations
Ajello, M.; Marchesi, S.; Baloković, M. +2 more
In modeling the X-ray spectra of active galactic nuclei (AGNs), the inclination angle is a parameter that can play an important role in analyzing the X-ray spectra of AGNs, but it has never been studied in detail. We present a broadband X-ray spectral analysis of the joint Nuclear Spectroscopic Telescope Array-XMM-Newton observations of 13 sources…
Extinction-free Census of AGNs in the AKARI/IRC North Ecliptic Pole Field from 23-band infrared photometry from Space Telescopes
Hashimoto, Tetsuya; Goto, Tomotsugu; Kim, Seong Jin +21 more
In order to understand the interaction between the central black hole and the whole galaxy or their co-evolution history along with cosmic time, a complete census of active galactic nucleus (AGN) is crucial. However, AGNs are often missed in optical, UV, and soft X-ray observations since they could be obscured by gas and dust. A mid-infrared (MIR)…
The Warm-Hot, Extended, Massive Circumgalactic Medium of NGC 3221: An XMM-Newton Discovery
Mathur, Smita; Gupta, Anjali; Das, Sanskriti
Using Suzaku data, we had found a 3.4σ evidence for the X-ray emitting warm-hot circumgalactic medium (CGM) in the L⋆ galaxy NGC 3221. Here we present XMM-Newton data and outline an efficient, rigorous, and well-defined method to extract the faint CGM signal. We confirm the CGM detection at 4σ significance within 30-200 kpc of the galax…
HD 191939: Three Sub-Neptunes Transiting a Sun-like Star Only 54 pc Away
Barclay, Thomas; Vanderburg, Andrew; Mikal-Evans, Thomas +38 more
We present the discovery of three sub-Neptune-sized planets transiting the nearby and bright Sun-like star HD 191939 (TIC 269701147, TOI 1339), a Ks = 7.18 mag G8 V dwarf at a distance of only 54 pc. We validate the planetary nature of the transit signals by combining 5 months of data from the Transiting Exoplanet Survey Satellite with …