Search Publications
AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817
Gorjian, Varoujan; Kaspi, Shai; Hall, Patrick B. +49 more
We fit the UV/optical lightcurves of the Seyfert 1 galaxy Mrk 817 to produce maps of the accretion disk temperature fluctuations δ T resolved in time and radius. The δ T maps are dominated by coherent radial structures that move slowly (v ≪ c) inward and outward, which conflicts with the idea that disk variability is driven only by reverberation. …
Probing the Heights and Depths of Y Dwarf Atmospheres: A Retrieval Analysis of the JWST Spectral Energy Distribution of WISE J035934.06–540154.6
Cushing, Michael C.; Kirkpatrick, J. Davy; Marley, Mark S. +5 more
We present an atmospheric retrieval analysis of the Y0 brown dwarf WISE J035934.06‑540154.6 using the low-resolution 0.96–12 µm James Webb Space Telescope (JWST) spectrum presented in Beiler et al. We obtain volume number mixing ratios of the major gas-phase absorbers (H2O, CH4, CO, CO2, PH3, and H…
Strategies for Obtaining Robust Spectral Energy Distribution Fitting Parameters for Galaxies at z ∼ 1 and z ∼ 2 in the Absence of Infrared Data
Salim, Samir; Osborne, Chandler
Robust estimation of star formation rates (SFRs) at higher redshifts (z ≳ 1) using UV–optical–near-infrared (NIR) photometry is contingent on the ability of spectral energy distribution (SED) fitting to constrain the dust attenuation, stellar metallicity, and star formation history (SFH) simultaneously. IR-derived dust luminosities can help break …
Discovery of Optically Emitting Circumgalactic Nebulae around the Majority of UV-luminous Quasars at Intermediate Redshift
Contini, Thierry; Johnson, Sean D.; Petitjean, Patrick +15 more
We report the discovery of large, ionized, [O II]-emitting circumgalactic nebulae around the majority of 30 UV-luminous quasars at z = 0.4–1.4 observed with deep, wide-field integral field spectroscopy with the Multi-Unit Spectroscopy Explorer (MUSE) by the Cosmic Ultraviolet Baryon Survey and MUSE Quasar Blind Emitters Survey. Among the 30 quasar…
PHANGS-ML: Dissecting Multiphase Gas and Dust in Nearby Galaxies Using Machine Learning
Sandstrom, Karin M.; Leroy, Adam K.; Rosolowsky, Erik +25 more
The PHANGS survey uses Atacama Large Millimeter/submillimeter Array, Hubble Space Telescope, Very Large Telescope, and JWST to obtain an unprecedented high-resolution view of nearby galaxies, covering millions of spatially independent regions. The high dimensionality of such a diverse multiwavelength data set makes it challenging to identify new t…
JWST and ALMA Discern the Assembly of Structural and Obscured Components in a High-redshift Starburst Galaxy
Casey, Caitlin M.; Kartaltepe, Jeyhan S.; Koekemoer, Anton M. +27 more
We present observations and analysis of the starburst PACS-819 at z = 1.45 (M * = 1010.7 M ⊙), using high-resolution (0.″1; 0.8 kpc) Atacama Large Millimeter/submillimeter Array (ALMA) and multiwavelength JWST images from the COSMOS-Web program. Dissimilar to Hubble Space Telescope (HST) ACS images in the rest-fram…
A Pileup of Coronal Mass Ejections Produced the Largest Geomagnetic Storm in Two Decades
Wang, Rui; Liu, Ying D.; Hu, Huidong +2 more
The largest geomagnetic storm in two decades occurred in 2024 May with a minimum D st of ‑412 nT. We examine its solar and interplanetary origins by combining multipoint imaging and in situ observations. The source active region, NOAA AR 13664, exhibited extraordinary activity and produced successive halo eruptions, which were responsib…
Powerful Radio-loud Quasars Are Triggered by Galaxy Mergers in the Cosmic Bright Ages
Baum, Stefi A.; O'Dea, Christopher P.; Perlman, Eric S. +15 more
While supermassive black holes are ubiquitous features of galactic nuclei, only a small minority are observed during episodes of luminous accretion. The physical mechanism(s) driving the onset of fueling and ignition in these active galactic nuclei (AGN) are still largely unknown for many galaxies and AGN-selection criteria. Attention has focused …
The Stellar Distribution in Ultrafaint Dwarf Galaxies Suggests Deviations from the Collisionless Cold Dark Matter Paradigm
Trujillo, Ignacio; Sánchez Almeida, Jorge; Plastino, Angel R.
Unraveling the nature of dark matter (DM) stands as a primary objective in modern physics. Here we present evidence suggesting deviations from the collisionless cold DM (CDM) paradigm. It arises from the radial distribution of stars in six ultrafaint dwarf (UFD) galaxies measured with the Hubble Space Telescope. After a trivial renormalization in …
Small-amplitude Compressible Magnetohydrodynamic Turbulence Modulated by Collisionless Damping in Earth's Magnetosheath: Observation Matches Theory
Liu, Terry Z.; Zhao, Siqi; Yan, Huirong +2 more
Plasma turbulence is a ubiquitous dynamical process that transfers energy across many spatial and temporal scales and affects energetic particle transport. Recent advances in the understanding of compressible magnetohydrodynamic (MHD) turbulence demonstrate the important role of damping in shaping energy distributions on small scales, yet its obse…