Carnegie Observatories

From protogalaxy through thick and thin: Why did the Milky Way evolve in three kinematic phases?

Abstract APOGEE and Gaia data suggest the Milky Way’s kinematic structure evolved through three distinct phases: a disordered protogalaxy, which ‘spun up’ into a thick stellar disk, and then ‘cooled down’ to a final cold, thin stellar disk. We use a suite of FIRE-2 cosmological z...

That’s So Retro: The Gaia-Sausage-Enceladus Merger Trajectory as the Origin of the Chemical Abundance Bimodality in the Milky Way Disk

Abstract The Milky Way (MW) is thought to have experienced a ∼3:1 mass-ratio merger event near redshift z ∼ 2 with a significantly retrograde trajectory. This now-disrupted dwarf galaxy is commonly known as the Gaia-Sausage-Enceladus (GSE). In this paper, we investigate the impac...

SN 2024iss: A Multiwavelength Exposé of a Type IIb Supernova with an Early-time Ultraviolet Spectrum and Shock-breakout Constraints

Abstract We present multiwavelength observations and analysis of SN 2024iss, a Type IIb supernova (SN IIb) located at ∼14 Mpc. The first Zwicky Transient Facility detection of SN 2024iss is ∼40 minutes after first light (one of the earliest detections of a SN IIb to date) and a H...

The Curious Case of Centaurus A II: On the Subject of the Quenched satellites

The satellite system of Centaurus A presents a curious cosmological puzzle: while the global population is consistent with theoretical expectations, its inner regions (d<150 kpc) exhibit a deficit of luminous satellite galaxies. Using the Galacticus semi-analytic model applied to...

The chromosomal genome sequence of the boulder star coral, Orbicella franksi (Gregory, 1895) (Scleractinia: Merulinidae)

We present a genome assembly from a specimen of Orbicella franksi (boulder star coral; Cnidaria; Anthozoa; Scleractinia; Merulinidae). The genome sequence has a total length of 496.97 megabases. Most of the assembly (95.24%) is scaffolded into 15 chromosomal pseudomolecules. The...

Hot blue progenitors of stellar-mass black holes

Abstract While the connection between massive stars and supernova explosions is well established observationally, the link between massive stars and black hole formation remains elusive. Some massive stars may collapse directly to black holes without a successful supernova, and m...

The Zooplankton International Geospatial dataset: A global repository of spatiotemporal freshwater zooplankton community composition data from lakes and reservoirs to support ecological research

Abstract Zooplankton transfer substantial energy in aquatic food webs and are used as indicators of environmental change. Syntheses of zooplankton community dynamics globally require datasets that span a wide range of environmental gradients; however, these datasets are limited d...