Search Publications
Discovery of a Dusty, Chemically Mature Companion to a z ∼ 4 Starburst Galaxy in JWST ERS Data
Spoon, Henrik; Stacey, Gordon; Vishwas, Amit +6 more
We report the discovery of two companion sources to a strongly lensed galaxy SPT0418-47 ("ring") at redshift 4.225, targeted by the JWST Early Release Science program. We confirm that these sources are at a similar redshift to the ring based on Hα detected in the NIRSpec spectrum and [C II] λ158 µm line from the Atacama Large Millimeter/subm…
First Observations of the Brown Dwarf HD 19467 B with JWST
Johnstone, Doug; Leisenring, Jarron; Huber, Daniel +21 more
We observed HD 19467 B with JWST's NIRCam in six filters spanning 2.5–4.6 µm with the long-wavelength bar coronagraph. The brown dwarf HD 19467 B was initially identified through a long-period trend in the radial velocity of the G3V star HD 19467. HD 19467 B was subsequently detected via coronagraphic imaging and spectroscopy, and characteri…
Discovery of Two Polars from a Crossmatch of ZTF and the SRG/eFEDS X-Ray Catalog
Riddle, Reed; Szkody, Paula; Mróz, Przemek +14 more
Magnetic cataclysmic variables (CVs) are luminous Galactic X-ray sources, which have been difficult to find in purely optical surveys due to their lack of outburst behavior. The eROSITA telescope on board the Spektr-RG mission is conducting an all-sky X-ray survey and recently released the public eROSITA Final Equatorial Depth Survey (eFEDS) catal…
Late-time Hubble Space Telescope Observations of AT 2018cow. II. Evolution of a UV-bright Underlying Source 2-4 Yr Post-discovery
Kilpatrick, Charles D.; Drout, Maria R.; Foley, Ryan J. +4 more
In this second of a two-paper series, we present a detailed analysis of three Hubble Space Telescope observations taken ~2-4 yr post-discovery, examining the evolution of a UV-bright underlying source at the precise position of AT 2018cow. While observations at ~2-3 yr post-discovery revealed an exceptionally blue (L ν ∝ ν 1.99
Understanding the Early Stages of Galaxy Formation Using Very Metal-poor Stars from the Hamburg/ESO Survey
Carollo, Daniela; Christlieb, Norbert; Tissera, Patricia B. +1 more
We explore the chemodynamical properties of a sample of very metal-poor (VMP) stars selected from the Hamburg/ESO survey, matched with Gaia EDR3, in the phase space identified by the three integrals of motion (L z , E, I 3). Disk and halo orbits are separated by using the criteria defined in Carollo & Chiba. We found 26 …
Spectroscopic Analysis of Milky Way Outer Halo Satellites: Aquarius II and Boötes II
Li, Ting S.; Simon, Joshua D.; Pace, Andrew B. +3 more
In this paper, we present a chemical and kinematic analysis of two ultrafaint dwarf galaxies (UFDs), Aquarius II (Aqu II) and Boötes II (Boo II), using Magellan/IMACS spectroscopy. We present the largest sample of member stars for Boo II (12), and the largest sample of red giant branch members with metallicity measurements for Aqu II (eight). In b…
UV and Hα HST Observations of Six GASP Jellyfish Galaxies
Scarlata, Claudia; Mingozzi, Matilde; Calzetti, Daniela +17 more
Star-forming, Hα-emitting clumps are found embedded in the gaseous tails of galaxies undergoing intense ram pressure stripping in galaxy clusters, so-called jellyfish galaxies. These clumps offer a unique opportunity to study star formation under extreme conditions, in the absence of an underlying disk and embedded within the hot intracluster medi…
The SOFIA Massive (SOMA) Star Formation Survey. IV. Isolated Protostars
Law, Chi-Yan; Telkamp, Zoie; Yang, Yao-Lun +13 more
We present ~10-40 µm SOFIA-FORCAST images of 11 isolated protostars as part of the SOFIA Massive (SOMA) Star Formation Survey, with this morphological classification based on 37 µm imaging. We develop an automated method to define source aperture size using the gradient of its background-subtracted enclosed flux and apply this to build…
High-resolution Spectroscopic Metallicities of Milky Way Cepheid Standards and Their Impact on the Leavitt Law and the Hubble Constant
Riess, Adam G.; Macri, Lucas M.; Marconi, Marcella +10 more
Milky Way Cepheid variables with accurate Hubble Space Telescope photometry have been established as standards for primary calibration of the cosmic distance ladder to achieve a percent-level determination of the Hubble constant (H 0). These 75 Cepheid standards are the fundamental sample for investigation of possible residual systemati…
Solar Flare Ribbon Fronts. I. Constraining Flare Energy Deposition with IRIS Spectroscopy
Polito, Vanessa; Xu, Yan; Kerr, Graham S. +2 more
Spectral lines formed at lower atmospheric layers show peculiar profiles at the "leading edge" of ribbons during solar flares. In particular, increased absorption of the BBSO/GST He I λ10830 line, as well as broad and centrally reversed profiles in the spectra of the Mg II and C II lines observed by the IRIS satellite, has been reported. In this w…