Search Publications
Cosmological Fast Optical Transients with the Zwicky Transient Facility: A Search for Dirty Fireballs
Kulkarni, S. R.; Filippenko, Alexei V.; Riddle, Reed +35 more
Dirty fireballs are a hypothesized class of relativistic massive-star explosions with an initial Lorentz factor Γinit below the Γinit ~ 100 required to produce a long-duration gamma-ray burst (LGRB), but which could still produce optical emission resembling LGRB afterglows. Here we present the results of a search for on-axis …
3D Morphology of Open Clusters in the Solar Neighborhood with Gaia EDR 3. II. Hierarchical Star Formation Revealed by Spatial and Kinematic Substructures
Tang, Shih-Yun; Pang, Xiaoying; Wang, Long +9 more
We identify members of 65 open clusters in the solar neighborhood using the machine-learning algorithm StarGO based on Gaia EDR3 data. After adding members of 20 clusters from previous studies we obtain 85 clusters, and study their morphology and kinematics. We classify the substructures outside the tidal radius into four categories: filamentary (…
The Great Dimming of Betelgeuse: A Surface Mass Ejection and Its Consequences
Dupree, Andrea K.; Montargès, Miguel; Strassmeier, Klaus G. +7 more
The bright supergiant, Betelgeuse (Alpha Orionis, HD 39801), underwent a historic optical dimming during 2020 January 27-February 13. Many imaging and spectroscopic observations across the electromagnetic spectrum were obtained prior to, during, and subsequent to this dimming event. These observations of Betelgeuse reveal that a substantial surfac…
HST/WFC3 Hα Direct-imaging Detection of a Pointlike Source in the Disk Cavity of AB Aur
Zhou, Yifan; Kraus, Adam L.; Bae, Jaehan +8 more
Accreting protoplanets enable the direct characterization of planet formation. As part of a high-contrast imaging search for accreting planets with the Hubble Space Telescope (HST) Wide Field Camera 3, we present Hα images of AB Aurigae (AB Aur), a Herbig Ae/Be star harboring a transition disk. The data were collected in two epochs of direct-imagi…
Observation of a Magnetic Switchback in the Solar Corona
Telloni, Daniele; Zank, Gary P.; Adhikari, Laxman +58 more
Switchbacks are sudden, large radial deflections of the solar wind magnetic field, widely revealed in interplanetary space by the Parker Solar Probe. The switchbacks' formation mechanism and sources are still unresolved, although candidate mechanisms include Alfvénic turbulence, shear-driven Kelvin-Helmholtz instabilities, interchange reconnection…
Red Spiral Galaxies at Cosmic Noon Unveiled in the First JWST Image
Inoue, Akio K.; Sugahara, Yuma; Fudamoto, Yoshinobu
In the first image of the James Webb Space Telescope (JWST) of SMACS J0723.3-7327, one of the most outstanding features is the emergence of a large number of red spiral galaxies, because such red spiral galaxies are only a few percent in the number fraction among nearby spiral galaxies. While these apparently red galaxies were already detected wit…
Opening the Era of Quasar-host Studies at High Redshift with JWST
Onoue, Masafusa; Silverman, John D.; Ding, Xuheng
We measure the host galaxy properties of five quasars with z ~ 1.6-3.5 selected from the Sloan Digital Sky Survey (SDSS) and AEGIS, which fall within the JWST/Hubble Space Telescope (HST) CEERS survey area. A point-spread function library is constructed based on stars in the full field of view of the data and used with the 2D image modeling tool g…
Tracing Lyα and LyC Escape in Galaxies with Mg II Emission
Giavalisco, Mauro; Garel, Thibault; Verhamme, Anne +29 more
Star-forming galaxies are considered the likeliest source of the H I ionizing Lyman continuum (LyC) photons that reionized the intergalactic medium at high redshifts. However, above z ≳ 6, the neutral intergalactic medium prevents direct observations of LyC. Therefore, recent years have seen the development of indirect indicators for LyC that can …
Hubble Space Telescope Observations of NGC 253 Dwarf Satellites: Three Ultra-faint Dwarf Galaxies
Caldwell, Nelson; Strader, Jay; Seth, Anil C. +8 more
We present deep Hubble Space Telescope (HST) imaging of five faint dwarf galaxies associated with the nearby spiral NGC 253 (D ≈ 3.5 Mpc). Three of these are newly discovered dwarf galaxies, while all five were found in the Panoramic Imaging Survey of Centaurus and Sculptor, a Magellan+Megacam survey to identify faint dwarfs and other substructure…
Reconstructing the Assembly of Massive Galaxies. I. The Importance of the Progenitor Effect in the Observed Properties of Quiescent Galaxies at z ≈ 2
Giavalisco, Mauro; Ji, Zhiyuan
We study the relationship between the morphology and star formation history (SFH) of 361 quiescent galaxies (QGs) at redshift <z obs> ≈ 2, with stellar mass $\mathrm{log}{M}_{* }\geqslant 10.3$ , selected with the UVJ technique. Taking advantage of panchromatic photometry covering the rest-frame UV-to-NIR spectral range ( ≈40 band…