Search Publications
Synthetic Gaia DR3 Surveys from the FIRE Cosmological Simulations of Milky Way-mass Galaxies
Sanderson, Robyn; Wetzel, Andrew; Necib, Lina +4 more
The third data release (DR3) of Gaia has provided a fivefold increase in the number of radial velocity measurements of stars, as well as a stark improvement in parallax and proper motion measurements. To help with studies that seek to test models and interpret Gaia DR3, we present nine Gaia synthetic surveys, based on three solar positions in thre…
Protosolar D-to-H Abundance and One Part per Billion PH3 in the Coldest Brown Dwarf
Fortney, Jonathan J.; Apai, Dániel; Marley, Mark +24 more
The coldest Y spectral type brown dwarfs are similar in mass and temperature to cool and warm (∼200–400 K) giant exoplanets. We can therefore use their atmospheres as proxies for planetary atmospheres, testing our understanding of physics and chemistry for these complex, cool worlds. At these cold temperatures, their atmospheres are cold enough fo…
eDIG-CHANGES. II. Project Design and Initial Results on NGC 3556
Bregman, Joel N.; Li, Hui; Martini, Paul +19 more
The extraplanar diffuse ionized gas (eDIG) represents ionized gases traced by optical/UV lines beyond the stellar extent of galaxies. We herein introduce a novel multislit narrow-band spectroscopy method to conduct spatially resolved spectroscopy of the eDIG around a sample of nearby edge-on disk galaxies (eDIG-CHANGES). In this paper, we introduc…
Kinematics of Supernova Remnants Using Multiepoch Maximum Likelihood Estimation: Chandra Observation of Cassiopeia A as an Example
Sato, Toshiki; Yamada, Shinya; Sakai, Yusuke +2 more
Decadal changes in a nearby supernova remnant (SNR) were analyzed using a multiepoch maximum likelihood estimation (MLE) approach. To achieve greater accuracy in capturing the dynamics of SNRs, kinematic features and point-spread function effects were integrated into the MLE framework. Using Cassiopeia A as a representative example, data obtained …
Fast Outflows and Luminous He II Emission in Dwarf Galaxies with Active Galactic Nuclei (AGN)
Tripp, Todd M.; Hamann, Fred; Veilleux, Sylvain +6 more
While stellar processes are believed to be the main source of feedback in dwarf galaxies, the accumulating discoveries of active galactic nuclei (AGN) in dwarf galaxies over recent years arouse the interest to also consider AGN feedback in them. Fast, AGN-driven outflows, a major mechanism of AGN feedback, have indeed been discovered in dwarf gala…
VLA FRAMEx. I. Wideband Radio Properties of the AGN in NGC 4388
Fischer, Travis C.; Secrest, Nathan J.; Johnson, Megan C. +5 more
We present the first results from Karl G. Jansky Very Large Array (VLA) observations as a part of the Fundamental Reference Active Galactic Nucleus (AGN) Monitoring Experiment, a program to understand the relationship between AGN accretion physics and wavelength-dependent position as a function of time. With this VLA survey, we investigate the rad…
Diurnal Ejection of Boulder Clusters on Comet 67P Lasting beyond 3 au
Keller, Horst Uwe; Shi, Xian; Güttler, Carsten +6 more
Ejection of large boulder-like debris is a vigorous form of cometary activity that is unlikely induced by water ice out-gassing alone but rather associated with the sublimation of super-volatile ices. Though perceived on several comets, the actual pattern and mechanism of such activity are still unclear. Here we report on a specialized observation…
Next-generation Accretion Disk Reflection Model: High-density Plasma Effects
Kallman, Timothy R.; Bautista, Manuel; Harrison, Fiona A. +5 more
Luminous accretion disks around black holes are expected to have densities of ∼1015‑1022 cm‑3, which are high enough that plasma physics effects become important. Many of these effects have been traditionally neglected in the calculation of atomic parameters, and therefore in photoionization models and ultimately a…
Artificial Intelligence Assisted Inversion (AIAI): Quantifying the Spectral Features of 56Ni of Type Ia Supernovae
Wang, Lifan; Hu, Lei; Brown, Peter J. +1 more
Following our previous study of Artificial Intelligence Assisted Inversion (AIAI) of supernova analyses, we train a set of deep neural networks based on the 1D radiative transfer code TARDIS to simulate the optical spectra of Type Ia supernovae (SNe Ia) between 10 and 40 days after the explosion. The neural networks are applied to derive the mass …
Photometry of Saturated Stars with Neural Networks
Kochanek, Christopher S.; Winecki, Dominik
We use a multilevel perceptron (MLP) neural network to obtain photometry of saturated stars in the All-Sky Automated Survey for Supernovae (ASAS-SN). The MLP can obtain fairly unbiased photometry for stars from g ≃ 4 to 14 mag, particularly compared to the dispersion (15%–85% 1σ range around the median) of 0.12 mag for saturated (g < 11.5 mag) …