Beyond our solar system, aurorae have been inferred from radio observations of isolated brown dwarfs (e.g. Hallinan et al. 2006; Kao et al. 2023). Within our solar system, giant planets have auroral emission with signatures across the electromagnetic spectrum including infrared emission of H3+ and methane. Isolated brown dwarfs with auroral signatures in the radio have been searched for corresponding infrared features but have only had null detections (e.g. Gibbs et al. 2022). CWISEP J193518.59-154620.3. (W1935 for short) is an isolated brown dwarf with a temperature of ~482 K. Here we report JWST observations of strong methane emission from W1935 at 3.326 microns. Atmospheric modeling leads us to conclude that a temperature inversion of ~300 K centered at 1-10 millibar replicates the feature. This represents an atmospheric temperature inversion for a Jupiter-like atmosphere without irradiation from a host star. A plausible explanation for the strong inversion is heating by auroral processes, although other internal and/or external dynamical processes cannot be ruled out. The best fit model rules out the contribution of H3+ emission which is prominent in solar system gas giants however this is consistent with rapid destruction of H3+ at the higher pressure where the W1935 emission originates (e.g. Helling et al. 2019).

Jacqueline K. Faherty Ben Burningham Jonathan Gagné Genaro Suárez Johanna M. Vos Sherelyn Alejandro Merchan Caroline V. Morley Melanie Rowland Brianna Lacy Rocio Kiman Dan Caselden J. Davy Kirkpatrick Aaron Meisner Adam C. Schneider Marc Jason Kuchner Daniella Carolina Bardalez Gagliuffi Charles Beichman Peter Eisenhardt Christopher R. Gelino Ehsan Gharib-Nezhad Eileen Gonzales Federico Marocco Austin James Rothermich Niall Whiteford

An example of a sequence of the sl(N;C) chiral fields, for N$\geq 2$, tending to the complex heavenly metric (nonlinear graviton) of the type [4]x[-] when N --> infinity is given.

Maciej Przanowski Sebastian Formanski Francisco J. Turrubiates

We investigate the dependence of stellar disc scale lengths on environment for a sample of Sloan Digital Sky Survey Data Release 7 galaxies with published photometric bulge-disc decompositions. We compare disc scale lengths at fixed bulge mass for galaxies in an isolated field environment to galaxies in X-ray rich and X-ray poor groups. At low bulge mass, stellar disc scale lengths in X-ray rich groups are smaller compared to discs in both X-ray poor groups and in isolated field environments. This decrease in disc scale length is largely independent of halo mass, though shows some dependence on group-centric distance. We also find that stellar disc scale lengths are smaller in X-ray rich environments for a subset of star-forming galaxies and for galaxies of different morphological types. We note that disc scale lengths of low mass galaxies are known to have large systematic uncertainties, however we focus on differences between samples with the same measurement biases. Our results show that stellar disc scale lengths depend on X-ray brightness, a tracer of IGM density, suggesting a role for hydrodynamic processes such as ram-pressure stripping and/or starvation.

Melanie L. Demers Laura C. Parker Ian D. Roberts

We prove Lojasiewicz inequalities for the harmonic map energy for maps from surfaces of positive genus into general analytic target manifolds which are close to simple bubble trees and as a consequence obtain new results on the convergence of harmonic map flow and on the energy spectrum of harmonic maps with small energy. Our results and techniques are not restricted to particular targets or to integrable settings and we are able to lift general Lojasiewicz-Simon inequalities valid near harmonic maps $\hat \omega:S^2\to N$ to the singular setting whenever the bubble $\hat \omega$ is attached at a point which is not a branch point.

Melanie Rupflin

We survey a current, heated debate in the AI research community on whether large pre-trained language models can be said to "understand" language -- and the physical and social situations language encodes -- in any important sense. We describe arguments that have been made for and against such understanding, and key questions for the broader sciences of intelligence that have arisen in light of these arguments. We contend that a new science of intelligence can be developed that will provide insight into distinct modes of understanding, their strengths and limitations, and the challenge of integrating diverse forms of cognition.

Melanie Mitchell David C. Krakauer

As the energy of any map $v$ from $S^2$ to $S^2$ is at least $4\pi \vert deg(v)\vert$ with equality if and only if $v$ is a rational map one might ask whether maps with small energy defect $\delta_v=E(v)-4\pi \vert deg(v)\vert$ are necessarily close to a rational map. While such a rigidity statement turns out to be false for maps of general degree, we will prove that any map $v$ with small energy defect is essentially given by a collection of rational maps that describe the behaviour of $v$ at very different scales and that the corresponding distance is controlled by a quantitative rigidity estimate of the form $dist^2\leq C \delta_v(1+\vert\log\delta_v\vert)$ which is indeed sharp.

Melanie Rupflin

In the coming age of precision neutrino physics, neutrinos from the Sun become robust probes of the conditions of the solar core. Here, we focus on $^8$B neutrinos, for which there are already high precision measurements by the Sudbury Neutrino Observatory and Super-Kamiokande. Using only basic physical principles and straightforward statistical tools, we estimate projected constraints on the temperature and density of the $^8$B neutrino production zone compared to a reference solar model. We outline how to better understand the astrophysics of the solar interior using forthcoming neutrino data and solar models. Finally, we note that detailed forward modeling will be needed to develop the full potential of this approach.

Melanie A. Zaidel John F. Beacom

We construct a large class of conformal interfaces between two-dimensional c=1 conformal field theories describing compact free bosons and their Z_2 orbifolds. The interfaces are obtained by constructing boundary states in the corresponding c=2 product theories and applying the unfolding procedure. We compute the fusion products for all of these defects, and identify the invertible topological interfaces associated to global symmetries, the interfaces corresponding to marginal deformations, and the interfaces which map the untwisted sector of an orbifold to the invariant states of the parent theory.

Melanie Becker Yaniel Cabrera Daniel Robbins

The inner hundred parsecs of the Milky Way hosts the nearest supermassive black hole, largest reservoir of dense gas, greatest stellar density, hundreds of massive main and post main sequence stars, and the highest volume density of supernovae in the Galaxy. As the nearest environment in which it is possible to simultaneously observe many of the extreme processes shaping the Universe, it is one of the most well-studied regions in astrophysics. Due to its proximity, we can study the center of our Galaxy on scales down to a few hundred AU, a hundred times better than in similar Local Group galaxies and thousands of times better than in the nearest active galaxies. The Galactic Center (GC) is therefore of outstanding astrophysical interest. However, in spite of intense observational work over the past decades, there are still fundamental things unknown about the GC. JWST has the unique capability to provide us with the necessary, game-changing data. In this White Paper, we advocate for a JWST NIRCam survey that aims at solving central questions, that we have identified as a community: i) the 3D structure and kinematics of gas and stars; ii) ancient star formation and its relation with the overall history of the Milky Way, as well as recent star formation and its implications for the overall energetics of our galaxy's nucleus; and iii) the (non-)universality of star formation and the stellar initial mass function. We advocate for a large-area, multi-epoch, multi-wavelength NIRCam survey of the inner 100\,pc of the Galaxy in the form of a Treasury GO JWST Large Program that is open to the community. We describe how this survey will derive the physical and kinematic properties of ~10,000,000 stars, how this will solve the key unknowns and provide a valuable resource for the community with long-lasting legacy value.

Rainer Schoedel Steve Longmore Jonny Henshaw Adam Ginsburg John Bally Anja Feldmeier Matt Hosek Francisco Nogueras Lara Anna Ciurlo Mélanie Chevance J. M. Diederik Kruijssen Ralf Klessen Gabriele Ponti Pau Amaro-Seoane Konstantina Anastasopoulou Jay Anderson Maria Arias Ashley T. Barnes Cara Battersby Giuseppe Bono Lucía Bravo Ferres Aaron Bryant Miguel Cano Gonzáalez Santi Cassisi Leonardo Chaves-Velasquez Francesco Conte Rodrigo Contreras Ramos Angela Cotera Samuel Crowe Enrico di Teodoro Tuan Do Frank Eisenhauer Rei Enokiya Rubén Fedriani Jennifer K. S. Friske Dimitri Gadotti Carme Gallart Teresa Gallego Calvente Eulalia Gallego Cano Pablo García Fuentes Macarena García Marín Angela Gardini Abhimat K. Gautam Andrea Ghez Stefan Gillessen Naoteru Gouda Alessia Gualandris Mario Giuseppe Guarcello Robert Gutermuth Daryl Haggard Matthew Hankins Yue Hu Rebecca Houghton Ryohei Kano Jens Kauffmann Ryan Lau Alexandre Lazarian Mattia Libralato Anan Lu Xing Lu Jessica R. Lu Nora Luetzgendorf John Magorrian Shifra Mandel Sera Markoff Álvaro Martínez Arranz Alessandra Mastrobuono-Battisti Maria Melamed Elisabeth Mills Kaya Mori Mark Morris Elena Murchikova Tetsuya Nagata Francisco Najarro Govind Nandakumar David Nataf Nadine Neumayer Shogo Nishiyama Masayoshi Nobukawa Dylan M Paré Florian Peissker Maya Petkova Thushara G. S. Pillai Mike Rich Carlos Román Michael Rugel Nils Ryde Nadeen Sabha Joel Sánchez Bermúdez Álvaro Sánchez-Monge Mathias Schultheis Lijing Shao Hiroko Shinnaga Janet Simpson Shunya Takekawa Jonathan C. Tan Brian Thorsbro Pablo Torne Robin Goppala Tress Hideki Uchiyam Elena Valenti Roeland van der Marel Sill Verberne Pierre Vermot Sebastiano von Fellenberg Daniel Walker Gunther Witzel Siyao Xu Taihei Yano Farhad Yusef-Zadeh Michal Zajaček Manuela Zoccali

We examine, through a Boltzmann equation approach, the generating action of hard thermal loops in the background of gravitational fields. Using the gauge and Weyl invariance of the theory at high temperature, we derive an explicit closed-form expression for the effective action.

R. R. Francisco J. Frenkel J. C. Taylor