Search Publications
Star Formation Suppression by Tidal Removal of Cold Molecular Gas from an Intermediate-redshift Massive Post-starburst Galaxy
Bezanson, Rachel; Kriek, Mariska; Greene, Jenny E. +7 more
Observations and simulations have demonstrated that star formation in galaxies must be actively suppressed to prevent the formation of overly massive galaxies. Galactic outflows driven by stellar feedback or supermassive black hole accretion are often invoked to regulate the amount of cold molecular gas available for future star formation but may …
The homogeneity of chemical abundances in H II regions of the Magellanic Clouds
García-Rojas, J.; Esteban, C.; Rodríguez, M. +2 more
We use very deep spectra obtained with the Ultraviolet-Visual Echelle Spectrograph at the Very Large Telescope to derive physical conditions and chemical abundances of four H II regions of the Large Magellanic Cloud (LMC) and four H II regions of the Small Magellanic Cloud (SMC). The observations cover the spectral range 3100-10400 Å with a spectr…
A complex multiphase DLA associated with a compact group at z = 2.431 traces accretion, outflows, and tidal streams
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +4 more
As part of our program to identify host galaxies of known z = 2-3 Mg II absorbers with the Keck Cosmic Web Imager (KCWI), we discovered a compact group giving rise to a z = 2.431 DLA with ultrastrong Mg II absorption in quasar field J234628+124859. The group consists of four star-forming galaxies within 8-28 kpc and v ~ 40-340 km s-1 of…
Evidence of a complex structure within the 2013 August 19 coronal mass ejection. Radial and longitudinal evolution in the inner heliosphere
Jian, L. K.; Rodríguez-Pacheco, J.; Zouganelis, I. +9 more
Context. Late on 2013 August 19, a coronal mass ejection (CME) erupted from an active region located near the far-side central meridian from Earth's perspective. The event and its accompanying shock were remotely observed by the STEREO-A, STEREO-B, and SOHO spacecraft. The interplanetary counterpart (ICME) was intercepted by MESSENGER near 0.3 au …
Kinematic footprint of the Milky Way spiral arms in Gaia EDR3
Pérez-Villegas, Angeles; Martinez-Medina, Luis; Peimbert, Antonio
The Milky Way spiral arms are well established from star counts as well as from the locus of molecular clouds and other young objects; however, they have only recently started to be observed from a kinematics point of view. Using the kinematics of thin disc stars in Gaia EDR3 around the extended solar neighbourhood, we create x-y projections colou…
METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble Program. IV. Calibration of Dust Depletions versus Abundance Ratios in the Milky Way and Magellanic Clouds and Application to Damped Lyα Systems
Jenkins, Edward B.; Yanchulova Merica-Jones, Petia; Gordon, Karl D. +9 more
The evolution of the metal content of the universe can be tracked through rest-frame UV spectroscopy of damped Lyα systems (DLAs). Gas-phase abundances in DLAs must be corrected for dust depletion effects, which can be accomplished by calibrating the relation between abundance ratios such as [Zn/Fe] and depletions (the fraction of metals in gas, a…
Coronal Mass Ejection Deformation at 0.1 au Observed by WISPR
Vourlidas, Angelos; Stenborg, Guillermo; Hess, Phillip +3 more
Although coronal mass ejections (CMEs) resembling flux ropes generally expand self-similarly, deformations along their fronts have been reported in observations and simulations. We present evidence of one CME becoming deformed after a period of self-similar expansion in the corona. The event was observed by multiple white-light imagers on 2021 Jan…
Near-Earth Sub-Alfvénic Solar Winds: Interplanetary Origins and Geomagnetic Impacts
Hajra, Rajkumar; Tsurutani, Bruce T.
The near-Earth solar wind is in general super-Alfvénic and supermagnetosonic. Using all available near-Earth solar wind measurements between 1973 and 2020, we identified 30 intervals with sub-Alfvénic solar winds. The majority (83%) of the events occurred within interplanetary coronal mass ejection magnetic clouds (MCs)/driver gases. These MC sub-…
Deep learning-based super-resolution and de-noising for XMM-newton images
Valtchanov, Ivan; Verdugo, Eva; Lieu, Maggie +6 more
The field of artificial intelligence based image enhancement has been rapidly evolving over the last few years and is able to produce impressive results on non-astronomical images. In this work, we present the first application of Machine Learning based super-resolution (SR) and de-noising (DN) to enhance X-ray images from the European Space Agenc…
Quasi-periodic Accelerations of Energetic Particles during a Solar Flare
Chen, Wei; Li, Dong
We report the observation of nonstationary quasi-periodic pulsations (QPPs) in high-energy particles during the impulsive phase of an X4.8 flare on 2002 July 23 (SOL2002-07-23T00:35). The X4.8 flare was simultaneously measured by the Reuven Ramaty High Energy Solar Spectroscopic Imager, Nobeyama Radio Polarimeters, and Nobeyama Radioheliograph. Th…