Search Publications
Measuring the Milky Way Vertical Potential with the Phase Snail in a Model-independent Way
Mao, Shude; Liu, Chao; Shen, Juntai +2 more
The vertical phase-space spiral (snail) is a direct sign of disequilibrium of the Milky Way's disk. Nevertheless, the wrapping of the phase snail contains information on the vertical potential. We propose a novel method to measure the vertical potential utilizing the intersections between the snail and z/V z axes, for which we know th…
Signatures of Tidal Disruption of the Hercules Ultrafaint Dwarf Galaxy
Erkal, Denis; Geha, Marla; Frebel, Anna +6 more
The Hercules ultrafaint dwarf galaxy (UFD) has long been hypothesized to be tidally disrupting, yet no conclusive evidence has been found for tidal disruption owing partly to difficulties in identifying Hercules member stars. In this work, we present a homogeneous reanalysis of new and existing observations of Hercules, including the detection of …
AT 2023lli: A Tidal Disruption Event with Prominent Optical Early Bump and Delayed Episodic X-Ray Emission
Liu, Hao; Liu, Wei; Kong, Xu +42 more
High-cadence, multiwavelength observations have continuously revealed the diversity of tidal disruption events (TDEs), thus greatly advancing our knowledge and understanding of TDEs. In this work, we conducted an intensive optical-UV and X-ray follow-up campaign of TDE AT 2023lli and found a remarkable month-long bump in its UV/optical light curve…
FRESCO: The Paschen-α Star-forming Sequence at Cosmic Noon
Maseda, Michael V.; van Dokkum, Pieter; Reddy, Naveen A. +17 more
We present results from the JWST First Reionization Epoch Spectroscopically Complete Observations survey on the star-forming sequence (SFS) of galaxies at 1.0 < z < 1.7, around the peak of the cosmic star formation history. Star formation rates (SFRs) are measured from the redshifted, relatively dust-insensitive Paschen-α emission line, and …
The JWST Resolved Stellar Populations Early Release Science Program. VI. Identifying Evolved Stars in Nearby Galaxies
Gennaro, Mario; McQuinn, Kristen B. W.; Dolphin, Andrew E. +20 more
We present an investigation of evolved stars in the nearby star-forming galaxy Wolf–Lundmark–Melotte (WLM), using Near-Infrared Camera (NIRCam) imaging from the JWST Resolved Stellar Populations Early Release Science program. We find that various combinations of the F090W, F150W, F250M, and F430M filters can effectively isolate red supergiants and…
JWST Imaging of the Closest Globular Clusters. II. Discovery of Brown Dwarfs in NGC 6397 and Measurement of Age from the Brown Dwarf Cooling Sequence, Using SANDee—A New Grid of Model Isochrones across the Hydrogen-burning Limit
Anderson, Jay; Burgasser, Adam J.; Bedin, Luigi R. +4 more
Globular clusters contain vast repositories of metal-poor stars that represent some of the oldest stellar generations in the Universe. The archaeological footprint of early Galactic evolution may be retained in the measurable properties of globular clusters, such as their ages, mass functions, and chemical abundances. Until recently, all photometr…
Observations of the 2022 September 5 Solar Energetic Particle Event at 15 Solar Radii
Mitchell, D. G.; McComas, D. J.; Bale, S. D. +27 more
On 2022 September 5, Parker Solar Probe (Parker) observed a large solar energetic particle (SEP) event at the unprecedented distance of only 15 R S from the Sun. The observations from the Integrated Science Investigation of the Sun (IS⊙IS) obtained over the course of this event are remarkably rich, and an overview is presented here. IS⊙…
Observations of Extremely Metal-poor O Stars: Weak Winds and Constraints for Evolution Models
McQuinn, Kristen B. W.; Chisholm, John; Berg, Danielle A. +3 more
Metal-poor massive stars drive the evolution of low-mass galaxies, both locally and at high redshift. However, quantifying the feedback they impart to their local surroundings remains uncertain because models of stellar evolution, mass loss, and ionizing spectra are unconstrained by observations below 20% solar metallicity (Z ⊙). We pre…
JWST/NIRCam 4–5 µm Imaging of the Giant Planet AF Lep b
Salama, Maïssa; Perrin, Marshall D.; Pueyo, Laurent +23 more
With a dynamical mass of 3 M Jup, the recently discovered giant planet AF Lep b is the lowest-mass imaged planet with a direct mass measurement. Its youth and spectral type near the L/T transition make it a promising target to study the impact of clouds and atmospheric chemistry at low surface gravities. In this work, we present JWST/NI…
CLASSY. IX. The Chemical Evolution of the Ne, S, Cl, and Ar Elements
Ravindranath, Swara; Martin, Crystal L.; Kumari, Nimisha +20 more
To study the chemical evolution across cosmic epochs, we investigate Ne, S, Cl, and Ar abundance patterns in the Cosmic Origins Spectrograph Legacy Archive Spectroscopic SurveY (CLASSY). CLASSY comprises local star-forming galaxies (SFGs; 0.02 < z < 0.18) with enhanced star formation rates, making them strong analogues to high-z SFGs. With d…