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The infalling elliptical galaxy M89: the chemical composition of the AGN disturbed hot atmosphere
Werner, Norbert; Mernier, François; Ercan, E. Nihal +4 more
The chemical enrichment of X-ray-emitting hot atmospheres has hitherto been primarily studied in galaxy clusters. These studies revealed relative abundances of heavy elements that are remarkably similar to Solar. Here, we present measurements of the metal content of M89 (NGC 4552), an elliptical galaxy infalling into the Virgo cluster with a ~10 k…
Characterisation of the X-ray point source variability in the eROSITA south ecliptic pole field
Salvato, M.; Buchner, J.; Nandra, K. +11 more
Aims: During the Spectrum Roentgen Gamma (SRG)/eROSITA all-sky surveys, X-ray sources close to the South Ecliptic Pole (SEP) are observed almost every 4 h. We aim to identify the sources exhibiting the most significant long-term X-ray variability within 3° of the SEP in the first three surveys, and investigate their properties.
Methods: …
Data-driven Stellar Intrinsic Colors and Dust Reddenings for Spectrophotometric Data: From the Blue-edge Method to a Machine Learning Approach
Ren, Yi; Wang, Shu; Jiang, Biwei +4 more
Intrinsic colors (ICs) of stars are essential for studies on both stellar physics and dust reddening. In this work, we developed an XGBoost model to predict ICs with the atmospheric parameters T eff,
Three-Dimensional Venus Cloud Structure Simulated by a General Circulation Model
Shao, Wencheng D.; Dai, Longkang; Mendonça, João. M.
The clouds have a great impact on Venus's energy budget and climate evolution, but its three-dimensional structure is still not well understood. Here we incorporate a simple Venus cloud physics scheme into a flexible GCM to investigate the three-dimensional cloud spatial variability. Our simulations show good agreement with observations in terms o…
The true nature of HE 0057-5959, the most metal-poor, Li-rich star
Salaris, M.; Bonifacio, P.; Monaco, L. +2 more
The Li-rich stars are a class of rare objects with a surface lithium abundance, A(Li), that exceeds that of other stars in the same evolutionary stage. The origin of these stars is still debated, and valuable routes to look at include the Cameron-Fowler mechanism, a mass-transfer process in a binary system, or the engulfment of rocky planets or br…
Identifying Plasma Fractionation Processes in the Chromosphere Using IRIS
Stangalini, Marco; Long, David M.; Testa, Paola +7 more
The composition of the solar corona differs from that of the photosphere, with the plasma thought to fractionate in the solar chromosphere according to the first ionization potential (FIP) of the different elements. This produces a FIP bias, wherein elements with a low FIP are preferentially enhanced in the corona compared to their photospheric ab…
Radial velocity homogeneous analysis of M dwarfs observed with HARPS: I. Exoplanet detection and candidates
Bouchy, F.; Meunier, N.; Unger, N. +12 more
Context. The census of planets around M dwarfs in the solar neighbourhood meets two challenges: detecting the best targets for the future characterisation of planets with ELTs, and studying the statistics of planet occurrence that are crucial to formation scenarios. The radial velocity (RV) method remains the most appropriate for such a census as …
The Star Formation History of Nearby Galaxies: A Machine Learning Approach
Tian, Hao; Yang, Ming; Liu, Chao +2 more
Reproducing color–magnitude diagrams (CMDs) of star-resolved galaxies is one of the most precise methods for measuring the star formation history (SFH) of nearby galaxies back to the earliest time. The upcoming big data era poses challenges to the traditional numerical technique in its capacity to deal with vast amounts of data, which motivates us…
Hints of a close outer companion to the ultra-hot Jupiter TOI-2109 b
Alonso, R.; Deleuil, M.; Erikson, A. +86 more
Context. Hot Jupiters (HJs) with close-by planetary companions are rare, with only a handful of them having been discovered so far. This could be due to their suggested dynamical histories, which lead to the possible ejection of other planets. TOI-2109 b is special in this regard because it is the HJ with the closest relative separation from its h…
Exploring Unobscured Quasi-stellar Objects in the Southern Hemisphere with KS4
Im, Myungshin; Kim, Minjin; Song, Hyunmi +7 more
We present a catalog of unobscured quasi-stellar object (QSO) candidates in the Southern Hemisphere from the early interim data of the KMTNet Synoptic Survey of Southern Sky (KS4). The KS4 data covers ∼2500 deg2 sky area, reaching 5σ detection limits of ∼22.1–22.7 AB mag in the BVRI bands. Combining this with available infrared photomet…