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Searching for GEMS: TOI-5688 A b, a Low-density Giant Orbiting a High-metallicity Early M-dwarf
Kobulnicky, Henry A.; Cochran, William D.; Mahadevan, Suvrath +31 more
We present the discovery of a low-density planet orbiting the high-metallicity early M-dwarf TOI-5688 A b. This planet was characterized as part of the search for transiting giant planets (R ≳ 8 R⊕) through the Searching for Giant Exoplanets around M-dwarf Stars (GEMS) survey. The planet was discovered with the Transiting Exoplanet Surv…
Simultaneous Multiband Photometry of the Early Optical Afterglow of GRB 240825A with Mephisto
Kumar, Brajesh; Liu, Chenxu; Wang, Tao +19 more
Gamma-ray bursts (GRBs) are the most luminous transients in the Universe. The interaction of the relativistic jet with the circumburst medium produces an afterglow and generates multiwavelength emission. In this work, we present simultaneous multiband photometry of GRB 240825A with the Multi-channel Photometric Survey Telescope (Mephisto) and anal…
Chemical Evolution of R-process Elements in Stars (CERES): IV. An observational run-up of the third r-process peak with Hf, Os, Ir, and Pt
Hansen, Camilla Juul; Bonifacio, Piercarlo; Caffau, Elisabetta +8 more
Context. The third r-process peak (Os, Ir, Pt) is poorly understood due to observational challenges, with spectral lines located in the blue or near-ultraviolet region of stellar spectra. These challenges need to be overcome for a better understanding of the r-process in a broader context. Aims. To understand how the abundances of the third r-proc…
The ones that got away: chemical tagging of globular cluster-origin stars with Gaia BP/RP spectra
Belokurov, Vasily; Monty, Stephanie; Ardern-Arentsen, Anke +3 more
Globular clusters (GCs) are sites of extremely efficient star formation, and recent studies suggest they significantly contributed to the early Milky Way's stellar mass build-up. Although their role has since diminished, GCs' impact on the Galaxy's initial evolution can be traced today by identifying their most chemically unique stars - those with…
Time-resolved Hubble Space Telescope UV Observations of an X-Ray Quasiperiodic Eruption Source
Wevers, T.; Arcodia, R.; Pasham, D. R. +3 more
X-ray quasiperiodic eruptions (QPEs) are a novel mode of variability in nearby galactic nuclei whose origin remains unknown. Their multiwavelength properties are poorly constrained, as studies have focused almost entirely on the X-ray band. Here, we report on time-resolved, coordinated Hubble Space Telescope far-ultraviolet (FUV) and XMM-Newton X-…
A Comprehensive Study of Type I (Thermonuclear) Bursts in the New Transient SRGA J144459.2–604207
Chen, Yupeng; Zhang, Shu; Li, Xiaobo +11 more
We report an analysis of Insight-HXMT observations of the newly discovered accreting millisecond pulsar SRGA J144459.2–604207. During the outburst, detected in 2024 February by SRG/ART-XC, the broadband persistent spectrum was well fitted by an absorbed Comptonization model. We detected 60 type I X-ray bursts in the Insight-HXMT medium energy (ME)…
Deep view of the intracluster light in the Coma cluster of galaxies
Jiménez-Teja, Yolanda; Dupke, Renato A.; Román, Javier +6 more
The detection and study of the intracluster light (ICL) in rich clusters of galaxies has been a longstanding challenge and key focus. Using the lowest-surface-brightness images of the Coma cluster of galaxies in the g and r bands, from the Halos and Environment of Nearby Galaxies (HERON) Coma Cluster Project, we obtained the most extensive image o…
Jets Downstream of Collisionless Shocks: Recent Discoveries and Challenges
Raptis, Savvas; Blanco-Cano, Xóchitl; Karlsson, Tomas +19 more
Plasma flows with enhanced dynamic pressure, known as magnetosheath jets, are often found downstream of collisionless shocks. As they propagate through the magnetosheath, they interact with the surrounding plasma, shaping its properties, and potentially becoming geoeffective upon reaching the magnetopause. In recent years (since 2016), new researc…
Modelling the evolution of the Galactic disc scale height traced by open clusters
Moitinho, André; Moreira, Sandro; Silva, André +1 more
Context. The scale height (SH) of the spatial distribution of open clusters (OCs) in the Milky Way exhibits a well-known increase with age that is usually interpreted as evidence for dynamical heating of the disc or for the disc having been thicker in the past. Aims. We address the increase in the SH with age of the OC population from a different …
Eccentricities of Close Stellar Binaries
El-Badry, Kareem; Wu, Yanqin; Hadden, Sam +2 more
Orbits of stellar binaries are in general eccentric. These eccentricities encode information about their early lives. Here, we use thousands of main-sequence binaries from the Gaia DR3 catalog to reveal that binaries inward of a few astronomical units exhibit a simple Rayleigh distribution with a mode of σe ≃ 0.3. We find the same distr…