Search Publications
Confirmation of an Anomalously Low Dark Matter Content for the Galaxy NGC 1052-DF4 from Deep, High-resolution Continuum Spectroscopy
van Dokkum, Pieter; Shen, Zili; Danieli, Shany
NGC 1052-DF4 was found to be the second "galaxy lacking dark matter" in the NGC 1052 group, based on its velocity dispersion of ${\sigma }_{\mathrm{gc}}={4.2}_{-2.2}^{+4.4}$ km s-1 as measured from the radial velocities of seven of its globular clusters. Here we verify this result by measuring the stellar velocity dispersion of the gala…
The ELM Survey South. II. Two Dozen New Low-mass White Dwarf Binaries
Gianninas, A.; Kupfer, Thomas; Kilic, Mukremin +5 more
We present the results from our ongoing spectroscopic survey targeting low-mass white dwarf binaries, focusing on the southern sky. We used a Gaia DR2- and eDR3-based selection and identified 28 new binaries, including 19 new extremely low-mass (ELM) white dwarfs, one short period, likely eclipsing, DABZ, and two potential LISA binaries. We presen…
SPLUS J142445.34-254247.1: An r-process-enhanced, Actinide-boost, Extremely Metal-poor Star Observed with GHOST
Jones, David O.; Simpson, Chris; Placco, Vinicius M. +33 more
We report on a chemo-dynamical analysis of SPLUS J142445.34-254247.1 (SPLUS J1424-2542), an extremely metal-poor halo star enhanced in elements formed by the rapid neutron-capture process (r-process). This star was first selected as a metal-poor candidate from its narrowband S-PLUS photometry and followed up spectroscopically in medium resolution …
Discovery of the Magellanic Stellar Stream Out to 100 kpc
Conroy, Charlie; Ting, Yuan-Sen; Cargile, Phillip A. +7 more
The Magellanic Stream (MS)-an enormous ribbon of gas spanning 140° of the southern sky trailing the Magellanic Clouds-has been exquisitely mapped in the five decades since its discovery. However, despite concerted efforts, no stellar counterpart to the MS has been conclusively identified. This stellar stream would reveal the distance and 6D kinema…
Twenty-five Years of Accretion onto the Classical T Tauri Star TW Hya
Fang, Min; Edwards, Suzan; Herczeg, Gregory J. +39 more
Accretion plays a central role in the physics that governs the evolution and dispersal of protoplanetary disks. The primary goal of this paper is to analyze the stability over time of the mass accretion rate onto TW Hya, the nearest accreting solar-mass young star. We measure veiling across the optical spectrum in 1169 archival high-resolution spe…
The State of the Molecular Gas in Post-starburst Galaxies
Zabludoff, Ann I.; French, K. Decker; Narayanan, Desika +7 more
The molecular gas in galaxies traces both the fuel for star formation and the processes that can enhance or suppress star formation. Observations of the molecular gas state can thus point to when and why galaxies stop forming stars. In this study, we present Atacama Large Millimeter/submillimeter Array observations of the molecular gas in galaxies…
Observational Evidence of S-web Source of the Slow Solar Wind
Barczynski, K.; Peter, H.; Zhukov, A. N. +25 more
From 2022 March 18 to 21, NOAA Active Region (AR) 12967 was tracked simultaneously by Solar Orbiter at 0.35 au and Hinode/EIS at Earth. During this period, strong blueshifted plasma upflows were observed along a thin, dark corridor of open magnetic field originating at the AR's leading polarity and continuing toward the southern extension of the n…
JWST Peers into the Class I Protostar TMC1A: Atomic Jet and Spatially Resolved Dissociative Shock Region
Pontoppidan, K. M.; Bjerkeli, P.; Kristensen, L. E. +6 more
Outflows and winds launched from young stars play a crucial role in the evolution of protostars and the early stages of planet formation. However, the specific details of the mechanism behind these phenomena, including how they affect the protoplanetary disk structure, are still debated. We present JWST NIRSpec integral field unit observations of …
Giant Planet Engulfment by Evolved Giant Stars: Light Curves, Asteroseismology, and Survivability
Bildsten, Lars; Cantiello, Matteo; O'Connor, Christopher E. +1 more
About ten percent of Sun-like (1-2 M ⊙) stars will engulf a 1-10 M J planet as they expand during the red giant branch (RGB) or asymptotic giant branch (AGB) phase of their evolution. Once engulfed, these planets experience a strong drag force in the star's convective envelope and spiral inward, depositing energy and angular …
Cosmic Evolution of Gas and Star Formation
Staguhn, Johannes; Mobasher, Bahram; Capak, Peter +20 more
Atacama Large Millimeter/submillimeter Array (ALMA) observations of the long-wavelength dust continuum are used to estimate the gas masses in a sample of 708 star-forming galaxies at z = 0.3-4.5. We determine the dependence of gas masses and star formation efficiencies (SFEs; SFR per unit gas mass) on redshift (z), M *, and star formati…