Search Publications
On the Sizes of Ionized Bubbles Around Galaxies During the Reionization Epoch. The Spectral Shapes of the Lyα Emission from Galaxies
Scarlata, Claudia; Hayes, Matthew J.
We develop a new method to determine the distance between a high-redshift galaxy and a foreground screen of atomic hydrogen. In a partially neutral universe, and assuming spherical symmetry, this equates to the radius of an ionized "bubble" (R B) surrounding the galaxy. The method requires an observed Lyα equivalent width, its velocity …
Distant Echoes of the Milky Way's Last Major Merger
Conroy, Charlie; Ting, Yuan-Sen; Cargile, Phillip A. +9 more
The majority of the Milky Way's stellar halo consists of debris from our galaxy's last major merger, the Gaia-Sausage-Enceladus (GSE). In the past few years, stars from the GSE have been kinematically and chemically studied in the inner 30 kpc of our galaxy. However, simulations predict that accreted debris could lie at greater distances, forming …
JWST's PEARLS: A JWST/NIRCam View of ALMA Sources
Grogin, Norman A.; Hathi, Nimish P.; Holwerda, Benne W. +33 more
We report the results of James Webb Space Telescope/NIRCam observations of 19 (sub)millimeter sources detected by the Atacama Large Millimeter Array (ALMA). The accurate ALMA positions allowed unambiguous identifications of their NIRCam counterparts. Taking gravitational lensing into account, these represent 16 distinct galaxies in three fields an…
A JWST NIRSpec Phase Curve for WASP-121b: Dayside Emission Strongest Eastward of the Substellar Point and Nightside Conditions Conducive to Cloud Formation
Mikal-Evans, Thomas; Sing, David K.; Lothringer, Joshua D. +10 more
We present the first exoplanet phase-curve measurement made with the JWST NIRSpec instrument, highlighting the exceptional stability of this newly commissioned observatory for exoplanet climate studies. The target, WASP-121b, is an ultrahot Jupiter with an orbital period of 30.6 hr. We analyze two broadband light curves generated for the NRS1 and …
Constraints on Stellar Flare Energy Ratios in the NUV and Optical from a Multiwavelength Study of GALEX and Kepler Flare Stars
Kowalski, Adam F.; Tristan, Isaiah I.; Brasseur, C. E. +1 more
We present a multiwavelength study of stellar flares on primarily G-type stars using overlapping time domain surveys in the near-ultraviolet (NUV) and optical regimes. The NUV (the Galaxy Evolution Explorer; GALEX) and optical (Kepler) wavelength domains are important for understanding energy fractionations in stellar flares, and for constraining …
ALMA Observation of a z ≳ 10 Galaxy Candidate Discovered with JWST
Papovich, Casey; Finkelstein, Steven L.; Santini, Paola +12 more
We report the observation by the Atacama Large Millimeter/submillimeter Array (ALMA) of a z ≳ 10 galaxy candidate (GHZ1) discovered from the GLASS-JWST Early Release Science Program. Our ALMA program aims to detect the [O III] emission line at the rest-frame frequency 3393.0062 GHz (88.36 µm) and far-IR continuum emission with the spectral w…
The Dimorphos Boulder Swarm
Mutchler, Max; Jewitt, David; Li, Jing +1 more
We present deep Hubble Space Telescope images taken to examine the ejecta from the DART spacecraft impact into asteroid Dimorphos. The images reveal an extensive population of comoving boulders, the largest of which is ~7 m in diameter (geometric albedo 0.15 assumed). Measurements of 37 boulders show a mean sky-plane velocity dispersion of 0.30 ± …
JWST Insight into a Lensed HST-dark Galaxy and Its Quiescent Companion at z = 2.58
Fujimoto, Seiji; Kohno, Kotaro; Trebitsch, Maxime +13 more
Using the novel James Webb Space Telescope (JWST)/NIRCam observations in the A2744 field, we present a first spatially resolved overview of a Hubble Space Telescope (HST)-dark galaxy, spectroscopically confirmed at z = 2.58 with magnification µ ≈ 1.9. While being largely invisible at ~1 µm with NIRCam, except for sparse clumpy substruc…
Polarization Properties of the Weakly Magnetized Neutron Star X-Ray Binary GS 1826-238 in the High Soft State
Wu, Kinwah; Enoto, Teruaki; Turolla, Roberto +94 more
The launch of the Imaging X-ray Polarimetry Explorer (IXPE) on 2021 December 9 has opened a new window in X-ray astronomy. We report here the results of the first IXPE observation of a weakly magnetized neutron star, GS 1826-238, performed on 2022 March 29-31 when the source was in a high soft state. An upper limit (99.73% confidence level) of 1.3…
Beyond UVJ: Color Selection of Galaxies in the JWST Era
Papovich, Casey; Martis, Nicholas S.; Muzzin, Adam +8 more
We present a new rest-frame color-color selection method using synthetic u s - g s and g s - i s , (ugi) s colors to identify star-forming and quiescent galaxies. Our method is similar to the widely used U - V versus V - J (UVJ) diagram. However, UVJ suffers known systematics. Spectros…