Search Publications
Investigating the Dominant Environmental Quenching Process in UVCANDELS/COSMOS Groups
Finkelstein, Steven L.; Arrabal Haro, Pablo; Dickinson, Mark +36 more
We explore how the fraction of quenched galaxies changes in groups of galaxies with respect to the distance to the center of the group, redshift, and stellar mass to determine the dominant process of environmental quenching in 0.2 < z < 0.8 groups. We use new UV data from the UVCANDELS project in addition to existing multiband photometry to …
The Direct-method Oxygen Abundance of Typical Dwarf Galaxies at Cosmic High Noon
Richard, Johan; Siana, Brian; Freeman, William R. +5 more
We present a Keck/MOSFIRE rest-optical composite spectrum of 16 typical gravitationally lensed star-forming dwarf galaxies at 1.7 ≲ z ≲ 2.6 (z mean = 2.30), all chosen independent of emission-line strength. These galaxies have a median stellar mass of $\mathrm{log}{({M}_{* }/{M}_{\odot })}_{\mathrm{med}}={8.29}_{-0.43}^{+0.51}$ and a me…
Varstrometry for Off-nucleus and Dual Sub-kiloparsec Active Galactic Nuclei (VODKA): Very Long Baseline Array Searches for Dual or Off-nucleus Quasars and Small-scale Jets
Shen, Yue; Zakamska, Nadia L.; Lazio, Joseph +5 more
Dual and off-nucleus active supermassive black holes are expected to be common in the hierarchical structure formation paradigm, but their identification at parsec scales remains a challenge due to strict angular resolution requirements. We conducted a systematic study using the Very Long Baseline Array (VLBA) to examine 23 radio-bright candidate …
Evolution of the Radial Size and Expansion of Coronal Mass Ejections Investigated by Combining Remote and In Situ Observations
Lugaz, Noé; Zhuang, Bin; Scolini, Camilla +4 more
A fundamental property of coronal mass ejections (CMEs) is their radial expansion, which determines the increase in the CME radial size and the decrease in the CME magnetic field strength as the CME propagates. CME radial expansion can be investigated either by using remote observations or by in situ measurements based on multiple spacecraft in ra…
Accelerated Structural Evolution of Galaxies in a Starbursting Cluster at z = 2.51
Daddi, Emanuele; Lu, Shiying; Elbaz, David +11 more
Structural properties of cluster galaxies during their peak formation epoch, z ~ 2-4 provide key information on whether and how the environment affects galaxy formation and evolution. Based on deep Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) imaging toward the z = 2.51 cluster, J1001, we explore environmental effects on the structure, …
Strongest Coronal Magnetic Fields in Solar Cycles 23 and 24: Probing, Statistics, and Implications
Fleishman, Gregory D.; Anfinogentov, Sergey A.; Fedenev, Viktor V.
A strong coronal magnetic field, when present, manifests itself as bright microwave sources at high frequencies produced by the gyroresonant (GR) emission mechanism in thermal coronal plasma. The highest frequency at which this emission is observed is proportional to the absolute value of the strongest coronal magnetic field on the line of sight. …
X-Ray Studies of the Pulsar PSR J1420-6048 and Its TeV Pulsar Wind Nebula in the Kookaburra Region
Woo, Jooyun; An, Hongjun; Mori, Kaya +4 more
We present a detailed analysis of broadband X-ray observations of the pulsar PSR J1420-6048 and its wind nebula (PWN) in the Kookaburra region with Chandra, XMM-Newton, and NuSTAR. Using the archival XMM-Newton and new NuSTAR data, we detected 68 ms pulsations of the pulsar and characterized its X-ray pulse profile, which exhibits a sharp spike an…
Asteroseismic Modeling of 1153 Kepler Red Giant Branch Stars: Improved Stellar Parameters with Gravity-mode Period Spacings and Luminosity Constraints
Bi, Shaolan; Li, Yaguang; Bedding, Timothy R. +2 more
This paper reports the estimated stellar parameters of 1153 Kepler red giant branch stars determined with asteroseismic modeling. We use radial-mode oscillation frequencies, gravity-mode period spacings, Gaia luminosities, and spectroscopic data to characterize these stars. Compared with previous studies, we find that the two additional observed c…
Near-infrared Spectroscopy of Dense Ejecta Knots in the Outer Eastern Area of the Cassiopeia A Supernova Remnant
Koo, Bon-Chul; Lee, Jae-Joon; Yoon, Sung-Chul +1 more
The Cassiopeia A supernova remnant has a complex structure, manifesting the multidimensional nature of core-collapse supernova explosions. To further understand this, we carried out near-infrared multiobject spectroscopy on the ejecta knots located in the northeastern (NE) jet and Fe K plume regions, which are two distinct features in the outer ea…
A Candidate Dual QSO at Cosmic Noon
Lacy, Mark; Comerford, Julia M.; Simmons, Brooke D. +6 more
We report the discovery of a candidate dual QSO at z = 1.889, a redshift that is in the era known as "cosmic noon" where most of the universe's black hole and stellar mass growth occurred. The source was identified in Hubble Space Telescope WFC3/IR images of a dust-reddened QSO that showed two closely separated point sources at a projected distanc…