Search Publications
Molecular Gas Reservoirs in Massive Quiescent Galaxies at z 0.7 Linked to Late-time Star Formation
Johnson, Benjamin D.; Bezanson, Rachel; Rieke, Marcia +6 more
We explore how the presence of detectable molecular gas depends on the inferred star formation histories (SFHs) in eight massive, quiescent galaxies at z ~ 0.7. Half of the sample have clear detections of molecular gas, traced by CO(2-1). We find that the molecular gas content is unrelated to the rate of star formation decline prior to the most re…
First Census of Gas-phase Metallicity Gradients of Star-forming Galaxies in Overdense Environments at Cosmic Noon
Teplitz, Harry I.; Fan, Xiaohui; Cai, Zheng +8 more
We report the first spatially resolved measurements of gas-phase metallicity radial gradients in star-forming galaxies in overdense environments at z ≳ 2. The spectroscopic data are acquired by the MAMMOTH-Grism survey, a Hubble Space Telescope (HST) cycle 28 medium program. This program is obtaining 45 orbits of WFC3/IR grism spectroscopy in the …
Detection of Intracluster Globular Clusters in the First JWST Images of the Gravitational Lens Cluster SMACS J0723.3-7327 at z = 0.39
Lee, Myung Gyoon; Jang, In Sung; Bae, Jang Ho
We present a survey of globular clusters (GCs) in the massive gravitational lens cluster SMACS J0723.3-7327 at z = 0.39 based on the early released JWST/NIRCam images. In the color-magnitude diagrams of the point sources, we clearly find a rich population of intracluster GCs that are spread over a wide area of the cluster. Their ages, considering …
Updated Photometry of the Yellow Supergiant Progenitor and Late-time Observations of the Type IIb Supernova SN 2016gkg
Kilpatrick, Charles D.; Coulter, David A.; Foley, Ryan J. +4 more
We present Hubble Space Telescope (HST) observations of the Type IIb supernova (SN) SN 2016gkg at 652, 1698, and 1795 days from explosion with the Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3). Comparing to pre-explosion imaging from 2001 obtained with the Wide Field Planetary Camera 2, we demonstrate that SN 2016gkg is now fain…
Solar Energetic Particles Produced during Two Fast Coronal Mass Ejections
Wang, Yuming; Guo, Jingnan; Li, Xiaolei +1 more
Two recent extremely fast coronal mass ejections (CMEs) are of particular interest. The first one originated from the southern hemisphere on 2021 October 28 and caused strong solar energetic particle (SEP) events over a wide longitude range from Earth, STEREO-A, to Mars. However, the other one, originating from the center of the Earth-viewed solar…
An Intensity Mapping Constraint on the CO-galaxy Cross-power Spectrum at Redshift 3
Marrone, Daniel P.; Keating, Garrett K.; Keenan, Ryan P.
The abundance of cold molecular gas plays a crucial role in models of galaxy evolution. While deep spectroscopic surveys of CO emission lines have been a primary tool for measuring this abundance, the difficulty of these observations has motivated alternative approaches to studying molecular gas content. One technique, line intensity mapping, seek…
Lyman Continuum Galaxy Candidates in COSMOS
Hathi, Nimish; Rafelski, Marc; Wang, Xin +11 more
Star-forming galaxies are the sources likely to have reionized the universe. As we cannot observe them directly due to the opacity of the intergalactic medium at z ≳ 5, we study z ~ 3-5 galaxies as proxies to place observational constraints on cosmic reionization. Using new deep Hubble Space Telescope rest-frame UV F336W and F435W imaging (30 orbi…
A Strong Shock During a Nova Outburst: An Origin of Multiple Velocity Systems in Optical Spectra and of High-energy Emissions
Kato, Mariko; Hachisu, Izumi
We propose a theoretical explanation of absorption/emission line systems in classical novae based on a fully self-consistent nova explosion model. We found that a reverse shock is formed far outside the photosphere (≳1013 cm) because later-ejected mass with a faster velocity collides with earlier-ejected matter. Optically thick winds bl…
Discovery, Timing, and Multiwavelength Observations of the Black Widow Millisecond Pulsar PSR J1555-2908
Ransom, Scott M.; Michelson, P. F.; Halpern, Jules P. +21 more
We report the discovery of PSR J1555-2908, a 1.79 ms radio and gamma-ray pulsar in a 5.6 hr binary system with a minimum companion mass of 0.052 M ⊙. This fast and energetic ( $\dot{E}=3\times {10}^{35}$ erg s-1) millisecond pulsar was first detected as a gamma-ray point source in Fermi Large Area Telescope (LAT) sky survey o…
Age Spreads and Systematics in λ Orionis with Gaia DR2 and the SPOTS Tracks
Pinsonneault, Marc H.; Hillenbrand, Lynne A.; Cao, Lyra +1 more
In this paper we investigate the robustness of age measurements, age spreads, and stellar models in young pre-main-sequence stars. For this effort, we study a young cluster, λ Orionis, within the Orion star-forming complex. We use Gaia data to derive a sample of 357 targets with spectroscopic temperatures from spectral types or from the automated …