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Three-dimensional Shape Explains Star Formation Mystery of California and Orion A
Kainulainen, Jouni; Rezaei Kh., Sara
The new Gaia data release (EDR3) with improved astrometry has opened a new era in studying our Milky Way in fine detail. We use Gaia EDR3 astrometry together with 2MASS and WISE photometry to study two of the most massive molecular clouds in the solar vicinity: Orion A and California. Despite having remarkable similarities in the plane of the sky …
Quantifying Feedback from Narrow Line Region Outflows in Nearby Active Galaxies. IV. The Effects of Different Density Estimates on the Ionized Gas Masses and Outflow Rates
Rafelski, Marc; Fischer, Travis C.; Collins, Nicholas R. +9 more
Active galactic nuclei (AGN) can launch outflows of ionized gas that may influence galaxy evolution, and quantifying their full impact requires spatially resolved measurements of the gas masses, velocities, and radial extents. We previously reported these quantities for the ionized narrow-line region outflows in six low-redshift AGN, where the gas…
After The Fall: Resolving the Molecular Gas in Post-starburst Galaxies
Bell, Eric F.; Zabludoff, Ann I.; Walter, Fabian +8 more
Post-starburst (PSB), or "E + A," galaxies represent a rapid transitional phase between major, gas-rich mergers and gas-poor, quiescent, early-type galaxies. Surprisingly, many PSBs have been shown to host a significant interstellar medium (ISM), despite theoretical predictions that the majority of the star-forming gas should be expelled in active…
Investigating the Effect of Galaxy Interactions on Star Formation at 0.5 < z < 3.0
Hathi, Nimish P.; Kartaltepe, Jeyhan S.; Kocevski, Dale D. +24 more
Observations and simulations of interacting galaxies and mergers in the local universe have shown that interactions can significantly enhance the star formation rates (SFRs) and fueling of active galactic nuclei (AGN). However, at higher redshift, some simulations suggest that the level of star formation enhancement induced by interactions is lowe…
Alpha-Proton Differential Flow of the Young Solar Wind: Parker Solar Probe Observations
Bale, S. D.; Allen, R. C.; Raouafi, N. E. +5 more
The velocity of alpha particles relative to protons can vary depending on the solar wind type and distance from the Sun. Measurements from the previous spacecraft provided the alpha-proton differential velocities down to 0.3 au. The Parker Solar Probe (PSP) now enables insights into differential flows of the newly accelerated solar wind closer to …
Discovery of Eight "Main-sequence Radio Pulse Emitters" Using the GMRT: Clues to the Onset of Coherent Radio Emission in Hot Magnetic Stars
Neiner, Coralie; Wade, Gregg A.; Chandra, Poonam +6 more
Main-sequence radio pulse emitters (MRPs) are magnetic early-type stars from which periodic radio pulses, produced via electron cyclotron maser emission (ECME), are observed. Despite the fact that these stars can naturally offer suitable conditions for triggering ECME, only seven such stars have been reported so far within a span of more than two …
A Tilt in the Dark Matter Halo of the Galaxy
Conroy, Charlie; Ting, Yuan-Sen; Johnson, Benjamin D. +9 more
Recent observations of the stellar halo have uncovered the debris of an ancient merger, Gaia-Sausage-Enceladus (GSE), estimated to have occurred ≳8 Gyr ago. Follow-up studies have associated GSE with a large-scale tilt in the stellar halo that links two well-known stellar overdensities in diagonally opposing octants of the Galaxy (the Hercules-Aqu…
GOALS-JWST: Hidden Star Formation and Extended PAH Emission in the Luminous Infrared Galaxy VV 114
Frayer, D. T.; Inami, Hanae; Böker, Torsten +32 more
James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) images of the luminous infrared (IR) galaxy VV 114 are presented. This redshift ~0.020 merger has a western component (VV 114W) rich in optical star clusters and an eastern component (VV 114E) hosting a luminous mid-IR nucleus hidden at UV and optical wavelengths by dust lanes. With …
Diagnosing FU Ori-like Sources: The Parameter Space of Viscously Heated Disks in the Optical and Near-infrared
Herczeg, Gregory J.; Jose, Jessy; Johnstone, Doug +8 more
FU Ori-type objects (FUors) are decades-long outbursts of accretion onto young stars that are strong enough to viscously heat disks so that the disk outshines the central star. We construct models for FUor objects by calculating emission components from a steady-state viscous accretion disk, a passively-heated dusty disk, magnetospheric accretion …
AGN Selection Methods Have Profound Impacts on the Distributions of Host-galaxy Properties
Giavalisco, Mauro; Kirkpatrick, Allison; Ji, Zhiyuan +4 more
We present a comparative study of X-ray and IR active galactic nuclei (AGNs) at z ≈ 2 to highlight the important AGN selection effects on the distributions of host-galaxy properties. Compared with non-AGN star-forming galaxies (SFGs) on the main sequence, X-ray AGNs have similar median star formation (SF) properties, but their incidence (q AG…