Search Publications
Metallicity and Spectral Evolution of WASP 39b: The Limited Role of Hydrodynamic Escape
Miguel, Yamila; Kubyshkina, Daria; Louca, Amy J.
The recent observations on WASP-39 b by JWST have revealed hints of high metallicity within the atmosphere compared to its host star. There are various theories on how these high metallic atmospheres emerge. In this study, we closely investigate the impact of extreme escape in the form of hydrodynamic escape to see its impact on atmospheric metall…
Kinetic Alfvén Waves Excited by Multiple Free Energy Sources in the Magnetotail
Lakhina, G. S.; Singh, S. V.; Barik, K. C.
The generation of kinetic Alfvén waves (KAWs) is investigated through a three-component theoretical model incorporating ion beam and velocity shear as the sources of free energy in a non-Maxwellian κ-distributed plasmas. The model considers Maxwellian distributed background ions, drifting-Maxwellian beam ions, and κ-electrons as its constituent sp…
Examining the Properties of Low-luminosity Hosts of Type Ia Supernovae from ASAS-SN
Galbany, L.; Morrell, Nidia; Holoien, Thomas W. -S. +14 more
We present a spectroscopic analysis of 44 low-luminosity host galaxies of Type Ia supernovae (SNe Ia) detected by the All-Sky Automated Survey for Supernovae (ASAS-SN), using hydrogen, oxygen, and sulfur emission lines to measure metallicities and star formation rates. We find no statistically significant evidence that the star formation activity …
Spatially Resolved Recent Star Formation History in NGC 6946
Dolphin, Andrew; Telford, O. Grace; Koplitz, Brad +6 more
The nearby face-on star-forming spiral galaxy NGC 6946 is known as the Fireworks Galaxy due to its hosting an unusually large number of supernovae. We analyze its resolved near-ultraviolet stellar photometry measured from images taken with the Hubble Space Telescope's Wide Field Camera 3 with the F275W and F336W filters. We model the color-magnitu…
Searching for New Globular Clusters in M31 with Gaia EDR3
Niu, Zexi; Liu, Jifeng; Huang, Song +5 more
We have found 50 new globular cluster (GC) candidates around M31 with Gaia Early Data Release 3 (EDR3), with the help of Pan-STARRS1 DR1 magnitudes and Pan-Andromeda Archaeological Survey (PAndAS) images. Based on the latest Revised Bologna Catalog and simbad, we trained two random forest (RF) classifiers, the first one to distinguish extended sou…
SPT-CL J2215-3537: A Massive Starburst at the Center of the Most Distant Relaxed Galaxy Cluster
Mahler, Guillaume; Allen, Steven W.; Sharon, Keren +15 more
We present the discovery of the most distant, dynamically relaxed cool core cluster, SPT-CL J2215-3537 (SPT2215), and its central brightest cluster galaxy (BCG) at z = 1.16. Using new X-ray observations, we demonstrate that SPT2215 harbors a strong cool core with a central cooling time of 200 Myr (at 10 kpc) and a maximal intracluster medium cooli…
Two-point Correlation Function Studies for the Milky Way: Discovery of Spatial Clustering from Disk Excitations and Substructure
Yanny, Brian; Gardner, Susan; Hinkel, Austin
We introduce a two-particle correlation function (2PCF) for the Milky Way, constructed to probe spatial correlations in the orthogonal directions of the stellar disk in the Galactic cylindrical coordinates of R, ϕ, and z. We use this new tool to probe the structure and dynamics of the Galaxy using the carefully selected set of solar neighborhood s…
The Sun's Magnetic Power Spectra over Two Solar Cycles. I. Calibration between SDO/HMI and SOHO/MDI Magnetograms
Wang, Ruihui; Jiang, Jie; Luo, Yukun
The Sun's magnetic field is strongly structured over a broad range of scales. Magnetic spatial power spectral analysis provides a powerful tool for understanding the various scales of magnetic fields and their interactions with plasma motions. We aim to investigate the power spectra using spherical harmonic decomposition of high-resolution Solar a…
On the Metallicities and Kinematics of the Circumgalactic Media of Damped Lyα Systems at z 2.5
Urbano Stawinski, Stephanie M.; Hennawi, Joseph F.; Hafen, Zachary +7 more
We use medium- and high-resolution spectroscopy of close pairs of quasars to analyze the circumgalactic medium (CGM) surrounding 32 damped Lyα absorption systems (DLAs). The primary quasar sightline in each pair probes an intervening DLA in the redshift range 1.6 < z abs < 3.5, such that the secondary sightline probes absorption f…
A Simple Method for Predicting N H Variability in Active Galactic Nuclei
Marchesi, Stefano; Zhao, Xiurui; Ajello, Marco +4 more
The unified model of active galactic nuclei (AGNs) includes a geometrically thick obscuring medium to explain the differences between type I and type II AGNs as an effect of inclination angle. This medium is often referred to as the torus and is thought to be "clumpy" as the line-of-sight column density, N H, has been observed to vary i…