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New 511 keV Line Data Provide Strongest sub-GeV Dark Matter Constraints
Silk, Joseph; De la Torre Luque, Pedro; Balaji, Shyam
We explore the 511 keV emission associated with sub-GeV dark matter (DM) particles that can produce electron–positron pairs and form positronium after thermalizing. We use ∼16 yr of data from the Spectrometer on INTEGRAL to constrain DM properties, including the full positron propagation and losses, and the suppression of free electron density awa…
Fast-rotating massive Population III stars as possible sources of extreme N enrichment in high-redshift galaxies
Sibony, Yves; Nandal, Devesh; Tsiatsiou, Sophie
We present an analysis of the chemical compositions in high-redshift galaxies, with a focus on the nitrogen-enhanced galaxies GN-z11 and CEERS-1019. We used stellar models of massive stars with initial masses ranging from 9 to 120 M⊙ and various metallicities to deduce the chemical abundances of stellar ejecta for a few light elements (…
JWST NIRSpec High-resolution Spectroscopy of MACS0647–JD at z = 10.167: Resolved [O II] Doublet and Electron Density in an Early Galaxy
Hutchison, Taylor A.; Larson, Rebecca L.; Conselice, Christopher J. +26 more
We present JWST/NIRSpec high-resolution G395H/F290LP spectroscopy of MACS0647‑JD, a gravitationally lensed galaxy merger at z = 10.167. The new spectroscopy, which is acquired for the two lensed images (JD1 and JD2), detects and resolves emission lines in the rest-frame ultraviolet and blue optical, including the resolved [O II] λ λ3726, 3729 doub…
The Faint Satellite System of NGC 253: Insights into Low-density Environments and No Satellite Plane
Caldwell, Nelson; Strader, Jay; Seth, Anil C. +12 more
We have conducted a systematic search around the Milky Way (MW) analog NGC 253 (D = 3.5 Mpc), as a part of the Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS)—a Magellan+Megacam survey to identify dwarfs and other substructures in resolved stellar light around MW-mass galaxies outside of the Local Group. In total, NGC 253 has five sate…
The Occurrence of Small, Short-period Planets Younger than 200 Myr with TESS
Bieryla, Allyson; Latham, David W.; Quinn, Samuel N. +10 more
Within the first few hundreds of millions of years, many physical processes sculpt the eventual properties of young planets. NASA's Transiting Exoplanet Survey Satellite (TESS) mission has surveyed young stellar associations across the entire sky for transiting planets, providing glimpses into the various stages of planetary evolution. Using our o…
The Mira Distance to M101 and a 4% Measurement of H 0
Casertano, Stefano; Riess, Adam G.; Zakamska, Nadia L. +8 more
The giant spiral galaxy M101 is host to the nearest recent Type Ia supernova (SN 2011fe) and thus has been extensively monitored in the near-infrared to study the late-time light curve of the SN. Leveraging this existing baseline of observations, we derive the first Mira-based distance to M101 by discovering and classifying a sample of 211 Miras w…
A recently formed ocean inside Saturn's moon Mimas
Lainey, V.; Noyelles, B.; Rambaux, N. +4 more
Moons potentially harbouring a global ocean are tending to become relatively common objects in the Solar System1. The presence of these long-lived global oceans is generally betrayed by surface modification owing to internal dynamics2. Hence, Mimas would be the most unlikely place to look for the presence of a global ocean
JWST observations of 13CO2 ice. Tracing the chemical environment and thermal history of ices in protostellar envelopes
Manoj, P.; Narang, Mayank; Bourke, Tyler L. +38 more
The structure and composition of simple ices can be severely modified during stellar evolution by protostellar heating. Key to understanding the involved processes are thermal and chemical tracers that can be used to diagnose the history and environment of the ice. The 15.2 µm bending mode of 12CO2 in particular has proven to…
The Red Supergiant Progenitor of Type II Supernova 2024ggi
Wang, Xiaofeng; Zhang, Jujia; Mo, Jun +8 more
We present a detailed analysis of the progenitor and its local environment for the recently discovered Type II supernova (SN) 2024ggi at a distance of about 6.7 Mpc, by utilizing the pre-explosion images from the Hubble Space Telescope and Spitzer Space Telescope. The progenitor is identified as a red bright variable star, with absolute F814W-band…
The High-Redshift Gas-Phase Mass–Metallicity Relation in FIRE-2
Faucher-Giguère, Claude-André; Hayward, Christopher C.; Feldmann, Robert +2 more
The unprecedented infrared spectroscopic capabilities of JWST have provided high-quality interstellar medium metallicity measurements and enabled characterization of the gas-phase mass–metallicity relation (MZR) for galaxies at z ≳ 5 for the first time. We analyze the gas-phase MZR and its evolution in a high-redshift suite of FIRE-2 cosmological …