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The Evolution of Stellar X-Ray Activity and Angular Momentum as Seen by eROSITA, TESS, and Gaia
Stassun, Keivan G.; Kounkel, Marina
We have assembled a sample of ∼8200 stars with spectral types F5V–M5V, all having directly measured X-ray luminosities from eROSITA and rotation periods from TESS and having empirically estimated ages via their membership in stellar clusters and groups identified in Gaia astrometry (ages 3–500 Myr). This is the largest such study sample yet assemb…
Thermal Evolution of an Active Region Through Quiet and Flaring Phases as Observed by NuSTAR, XRT, and AIA
Reeves, Katharine K.; Grefenstette, Brian W.; Shih, Albert Y. +6 more
Solar active regions (ARs) contain a broad range of temperatures, with the thermal plasma distribution often observed to peak in the few millions of kelvin. Differential emission measure (DEM) analysis can allow instruments with diverse temperature responses to be used in concert to estimate this distribution. Nuclear Spectroscopic Telescope ARray…
Constraining the Progenitor of the Nearby Type II-P SN 2024ggi with Environmental Analysis
Niu, Zexi; Sun, Ning-Chen; Liu, Jifeng +3 more
The progenitors of Type II-P supernovae (SN) have been confirmed to be red supergiants. However, the upper mass limit of the directly probed progenitors is much lower than that predicted by current theories, and the accurate determination of the progenitor masses is key to understand the final fate of massive stars. Located at a distance of only 6…
Active Galactic Nuclei in the Green Valley at z ∼ 0.7
Ji, Zhiyuan; Rieke, Marcia; Williams, Christina C. +5 more
We present near-infrared (NIR) spectroscopy using the MMT and Magellan infrared spectrograph for a sample of 29 massive galaxies (
An analysis of spectroscopic, seismological, astrometric, and photometric masses of pulsating white dwarf stars
Kepler, S. O.; Córsico, Alejandro H.; Uzundag, Murat +3 more
Context. A central challenge in the field of stellar astrophysics lies in accurately determining the mass of stars, particularly when dealing with isolated ones. However, for pulsating white dwarf stars, the task becomes more tractable due to the availability of multiple approaches such as spectroscopy, asteroseismology, astrometry, and photometry…
A Statistical Study of Magnetic Flux Emergence in Solar Active Regions Prior to Strongest Flares
Abramenko, Valentina I.; Kutsenko, Alexander S.; Plotnikov, Andrei A.
Using the data on magnetic field maps and continuum intensity for Solar Cycles 23 and 24, we explored 100 active regions (ARs) that produced M5.0 or stronger flares. We focus on the presence/absence of the emergence of magnetic flux in these ARs 2–3 days before the strong flare onset. We found that 29 ARs in the sample emerged monotonically amidst…
TESSILATOR: a one-stop shop for measuring TESS rotation periods
Günther, H. M.; Binks, A. S.
We present a software package designed to produce photometric light curves and measure rotation periods from full-frame images taken by the Transiting Exoplanet Survey Satellite (TESS), which we name 'TESSILATOR'. TESSILATOR is the only publicly available code that will run a full light curve and rotation period ($P_{\rm rot}$) analysis based on j…
Ongoing and Fossil Large-scale Outflows Detected in a High-redshift Radio Galaxy: [C II] Observations of TN J0924-2201 at z = 5.174
Imanishi, Masatoshi; Kohno, Kotaro; Schramm, Malte +13 more
We present Atacama Large Millimeter/submillimeter Array observations of the [C II] 158 µm line and the underlying continuum emission of TN J0924‑2201, which is one of the most distant known radio galaxies at z > 5. The [C II] line and 1 mm continuum emission are detected at the host galaxy. The systemic redshift derived from the [C II] li…
Europa's H2O2: Temperature Insensitivity and a Correlation with CO2
Brown, Michael E.; de Kleer, Katherine; Trumbo, Samantha K. +1 more
H2O2 is part of Europa's water-ice radiolytic cycle and a potential source of oxidants to Europa's subsurface ocean. However, factors controlling the concentration of this critical surface species remain unclear. Though laboratory experiments suggest that Europa's H2O2 should be concentrated in the colde…
A model of light pseudoscalar dark matter
Chakdar, Shreyashi; Ghosh, Dilip Kumar; Hung, P. Q. +2 more
The EW-