Search Publications
Lyman Limit System with O VI in the Circumgalactic Environment of a Pair of Galaxies
Wendt, Martin; Muzahid, Sowgat; Narayanan, Anand +3 more
We report on the analysis of a multiphase Lyman limit system (LLS) at z = 0.39047 identified toward the background quasar FBQS J0209–0438. The O VI doublet lines associated with this absorber have a different profile from the low-ionization metals and H I. Ly α has a very broad H I (b ≈ 150 km s‑1) component well-aligned with one of the…
Pixel-level Terrain Processing of the Martian Surface from Moderate Resolution Images of Tianwen-1
Liu, Dingxin; Yan, Wei; Liu, Jianjun +3 more
The moderate-resolution camera (MoRIC) of the Tianwen-1 orbiter, China's first Mars exploration mission, is a frame-imaging scheme color camera. However, generating a precise digital elevation model (DEM) from these images faces challenges due to the presence of featureless and repetitive regions on the Martian surface. Traditional photogrammetric…
A Low Albedo, Thin, Resistant Unit in Oxia Planum, Mars: Evidence for an Airfall Deposit and Late-Stage Groundwater Activity at the ExoMars Rover Landing Site
Fawdon, P.; Grindrod, P. M.; Davis, J. M. +2 more
Oxia Planum, Mars, is the future landing site of the ExoMars Rosalind Franklin rover mission, which will search for preserved biosignatures in a phyllosilicate-bearing unit. Overlying the mission-important phyllosilicate-bearing rocks is a dark, capping unit—known here as the Low albedo, Thin, Resistant (LTR) unit—which may have protected the phyl…
Flare-accelerated Electrons in the Kappa Distribution from X-Ray Spectra with the Warm-target Model
Kontar, Eduard P.; Luo, Yingjie; Bhattacharjee, Debesh
X-ray observations provide important and valuable insights into the acceleration and propagation of nonthermal electrons during solar flares. Improved X-ray spectral analysis requires a deeper understanding of the dynamics of energetic electrons. Previous studies have demonstrated that the dynamics of accelerated electrons with a few thermal speed…
Amplitude and phase changes in TESS photometry of five short period weak-lined T Tauri stars
Koen, C.
The statistical technique 'Complex Demodulation' (CDM) is used to track the amplitude and phase changes of periodicities in five naked T Tauri stars. The periodicities are most likely caused by dark spots on the stellar surfaces, which are rotated into and out of view. Two of the stars (CD-56 1438, CD-72 248) show two independent periodicities, pr…
Magnetic Fields in a Sample of Planet-hosting M Dwarf Stars from Kepler, K2, and TESS Observed by APOGEE
Wanderley, Fábio; Cunha, Katia; Smith, Verne V. +8 more
Stellar magnetic fields have a major impact on space weather around exoplanets orbiting low-mass stars. From an analysis of Zeeman-broadened Fe I lines measured in near-infrared SDSS/APOGEE spectra, mean magnetic fields are determined for a sample of 29 M dwarf stars that host closely orbiting small exoplanets. The calculations employed the radiat…
Possible influence of Martian surface mineralogy on the detectability of atmospheric trace gases - mid-infrared simulation results
Błęcka, Maria I.
The paper focuses on the influence of the optical properties of Martian surface minerals on remotely detected gaseous components of the Martian atmosphere, when the spectrometer receives a combined signal from the Martian soil and atmosphere. Our considerations are primarily concerned with the detectability of methane, but the problem may also app…
A multiband look at ultraluminous X-ray sources in NGC 7424
Soria, Roberto; Russell, Thomas D.; Motch, Christian +2 more
We studied the multiband properties of two ultraluminous X-ray sources (2CXO J225728.9-410211 = X-1 and 2CXO J225724.7-410343 = X-2) and their surroundings, in the spiral galaxy NGC 7424. Both sources have approached X-ray luminosities LX ~ 1040 erg s-1 at some epochs. Thanks to a more accurate astrometric solution…
A Database for Simultaneous Observations of the Earth's Magnetosheath by Cluster and MMS Between 2017 and 2021
Voitcu, Gabriel; Echim, Marius; Munteanu, Costel +4 more
This paper describes a catalog of simultaneous observations of the Earth's magnetosheath by ESA's Cluster and NASA's MMS missions. The catalog is built from a visual inspection of summary plots provided by the two missions complemented by an analysis of high-resolution magnetic field data. The catalog includes 117 events when Cluster 4 and MMS 4 c…
Synthesis of Organic and Inorganic Compounds in Asymptotic Giant Branch Stars
Kwok, Sun
After the synthesis of carbon in the core of asymptotic giant branch (AGB) stars, carbon is dredged up to the surface by convection. Many carbon-based molecules are formed in the subsequently developed stellar wind. These include acetylene, which can link together to form benzene in post-AGB evolution. The emergence of the spectral signatures of a…