Search Publications
Upper limits of HO2 in the atmosphere of Mars from the ExoMars Trace Gas Orbiter
Montmessin, Franck; Belyaev, Denis A.; Fedorova, Anna A. +10 more
Odd-hydrogen (HO$_\mathrm{x}$) species have a crucial role in regulating the chemistry of the atmosphere of Mars and are important to understand some of the most fundamental aspects regarding its atmospheric composition such as the long-term stability of CO$_2$. Despite the key role of these species for our understanding of the Martian photochemis…
Modeling and Calibration of Gaia, Hipparcos, and Tycho-2 Astrometric Data for the Detection of Dark Companions
Feng, Fabo; Rui, Yicheng; Xuan, Yifan +1 more
Hidden within the Gaia satellite's multiple data releases lies a valuable cache of dark companions. To facilitate the efficient and reliable detection of these companions via combined analyses involving the Gaia, Hipparcos, and Tycho-2 catalogs, we introduce an astrometric modeling framework. This method incorporates analytical least-square minimi…
Discovery of a Bow-shock Nebula Around the Z Cam-type Cataclysmic Variable SY Cancri
Bond, Howard E.; Talbot, Jonathan; Carter, Calvin +3 more
We report the serendipitous discovery of a bow-shock nebula around the cataclysmic variable (CV) SY Cancri. In addition, SY Cnc lies near the edge of a faint Hα-emitting nebula with a diameter of about
Spatial distribution of plasma density and magnetic field amplitude in the dayside magnetosheath as a function of the IMF orientation
Lavraud, B.; Génot, V.; Jeandet, A. +5 more
The properties of the magnetosheath are of pivotal importance in determining the coupling between the magnetosphere and interplanetary medium. In particular, the magnetic flux pileup and plasma depletion layer (PDL) modify the boundary conditions of magnetopause reconnection. However, the spatial distribution of the magnetic field strength and pla…
Long Term X-Ray Spectral Variations of the Seyfert-1 Galaxy Mrk 279
Jeena, K.; Misra, Ranjeev; Akhila, K. +1 more
We present the results from a long term X-ray analysis of Mrk 279 during the period 2018–2020. We use data from multiple missions – AstroSat, NuSTAR and XMM-Newton, for the purpose. The X-ray spectrum can be modeled as a double Comptonization along with the presence of neutral Fe Kα line emission, at all epochs. We determined the source's X-ray fl…
Near-infrared Spectroscopy of the Sun and Solar Analog Star HD 76151: Compiling an Extensive Line List in the Y, J, H, and K Bands
Bilir, Selçuk; Şahin, Timur; Şentürk, Sena Aleyna +2 more
Determining the physical nature of a star requires precise knowledge of its stellar atmospheric parameters, including effective temperature, surface gravity, and metallicity. This study presents a new atomic line list covering a broad spectral range (1–2.5 µm; YJHK bands) for iron (Fe) and α-elements (Ca, Mg, Ti, Si) to improve stellar param…
Millinovae: A New Class of Transient Supersoft X-Ray Sources without a Classical Nova Eruption
Udalski, Andrzej; Mróz, Przemek; Szymański, Michał K. +18 more
Some accreting binary systems containing a white dwarf (such as classical novae or persistent supersoft sources) are seen to emit low-energy X-rays with temperatures of ∼ 106 K and luminosities exceeding 1035 erg s‑1. These X-rays are thought to originate from nuclear burning on the white dwarf surface, either caus…
Unraveling the birthplaces of NGC 2070's massive stars, tracked with MUSE and revealed with JWST
Castro, N.
The formation of massive O-type stars cannot be simply explained as a scaled-up version of the accretion mechanisms observed in lower-mass stars. Understanding these processes necessitates systematic studies of their early stages, which are challenging to identify. Forming massive stars remain embedded in their dense nursery clouds, and IR instrum…
Importance of the dusk-dawn interplanetary magnetic field component (IMF By) to magnetospheric convection in Earth's magnetotail plasma sheet
Chong, Ghai Siung; Pitkänen, Timo; Kullen, Anita
The solar wind and its embedded magnetic field, the interplanetary magnetic field (IMF) together with magnetic reconnection power the large-scale plasma and magnetic flux circulation in the Earth's magnetosphere-ionosphere system. This circulation is termed as convection and its strength is controlled by the north-south IMF component (IMF Bz). In …
The Sun's Large-Scale Flows I: Measurements of Differential Rotation & Torsional Oscillation
Basu, Sarbani; Pevtsov, Alexei A.; DeRosa, Marc L. +13 more
We have developed a comprehensive catalog of the variable differential rotation measured near the solar photosphere. This catalog includes measurements of these flows obtained using several techniques: direct Doppler, granule tracking, magnetic pattern tracking, global helioseismology, as well as both time-distance and ring-diagram methods of loca…