Search Publications
Differential Rotation of the Solar Chromosphere: A Century-long Perspective from Kodaikanal Solar Observatory Ca II K Data
Chatzistergos, Theodosios; Ermolli, Ilaria; Chatterjee, Subhamoy +5 more
Chromospheric differential rotation is a key component in comprehending the atmospheric coupling between the chromosphere and the photosphere at different phases of the solar cycle. In this study, we therefore utilize the newly calibrated multidecadal Ca II K spectroheliograms (1907-2007) from the Kodaikanal Solar Observatory (KoSO) to investigate…
Living with a Red Dwarf: X-Ray, UV, and Ca II Activity-Age Relationships of M Dwarfs
Engle, Scott G.
The vast majority of stars in the nearby stellar neighborhood are M dwarfs. Their low masses and luminosities result in slow rates of nuclear evolution and minimal changes to the stars' observable properties, even along astronomical timescales. However, they possess relatively powerful magnetic dynamos and resulting X-ray to UV (X-UV) activity, co…
Multiband Simultaneous Photometry of Type II SN 2023ixf with Mephisto and the Twin 50 cm Telescopes
Kumar, Brajesh; Liu, Chenxu; Yang, Yuan-Pei +13 more
SN 2023ixf, recently reported in the nearby galaxy M101 at a distance of 6.85 Mpc, was one of the closest and brightest core-collapse supernovae in the last decade. In this work, we present multiwavelength photometric observation of SN 2023ixf with the Multi-channel Photometric Survey Telescope (Mephisto) in the uvgr bands and with the twin 50 cm …
oMEGACat. II. Photometry and Proper Motions for 1.4 Million Stars in Omega Centauri and Its Rotation in the Plane of the Sky
Dreizler, S.; Anderson, J.; Milone, A. P. +15 more
Omega Centauri (ω Cen) is the most massive globular cluster of the Milky Way. It is thought to be the nucleus of an accreted dwarf galaxy because of its high mass and its complex stellar populations. To decipher its formation history and study its dynamics, we created the most comprehensive kinematic catalog for its inner region, by analyzing both…
A Hubble Space Telescope Search for r-Process Nucleosynthesis in Gamma-Ray Burst Supernovae
Covino, S.; Melandri, A.; Pian, E. +24 more
The existence of a secondary (in addition to compact object mergers) source of heavy element (r-process) nucleosynthesis, the core-collapse of rapidly rotating and highly magnetized massive stars, has been suggested by both simulations and indirect observational evidence. Here, we probe a predicted signature of r-process enrichment, a late-time (≳…
Compositional Metrics of Fast and Slow Alfvénic Solar Wind Emerging from Coronal Holes and Their Boundaries
Riley, Pete; Bale, Stuart D.; Bowen, Trevor A. +7 more
We seek to understand the composition and variability of fast solar wind (FSW) and slow Alfvénic solar wind emerging from coronal holes (CHs). We leverage an opportune conjunction between Solar Orbiter and Parker Solar Probe (PSP) during PSP Encounter 11 to include compositional diagnostics from the Solar Orbiter Heavy Ion Sensor as these variatio…
The Escape Velocity Profile of the Milky Way from Gaia DR3
Necib, Lina; Ou, Xiaowei; Lin, Tongyan +2 more
The escape velocity profile of the Milky Way offers a crucial and independent measurement of its underlying mass distribution and dark matter (DM) properties. Using a sample of stars from the third data release of Gaia with 6D kinematics and strict quality cuts, we obtain an escape velocity profile of the Milky Way from 4 to 11 kpc in Galactocentr…
Feedback in Emerging Extragalactic Star Clusters, FEAST: The Relation between 3.3 µm Polycyclic Aromatic Hydrocarbon Emission and Star Formation Rate Traced by Ionized Gas in NGC 628
Kotulla, Ralf; Östlin, Göran; Smith, Linda J. +23 more
We present maps of ionized gas (traced by Paα and Brα) and 3.3 µm polycyclic aromatic hydrocarbon (PAH) emission in the nearby spiral galaxy NGC 628, derived from new JWST/NIRCam data from the Feedback in Emerging extrAgalactic Star clusTers (FEAST) survey. With this data, we investigate and calibrate the relation between 3.3 µm PAH em…
The SAGA Survey. V. Modeling Satellite Systems around Milky Way–Mass Galaxies with Updated UNIVERSEMACHINE
Weiner, Benjamin; Geha, Marla; Behroozi, Peter +11 more
Environment plays a critical role in shaping the assembly of low-mass galaxies. Here, we use the UNIVERSEMACHINE (UM) galaxy–halo connection framework and Data Release 3 of the Satellites Around Galactic Analogs (SAGA) Survey to place dwarf galaxy star formation and quenching into a cosmological context. UM is a data-driven forward model that flex…
The Rise of the r-process in the Gaia-Sausage/Enceladus Dwarf Galaxy
Naidu, Rohan P.; Frebel, Anna; Limberg, Guilherme +2 more
Neutron star mergers (NSMs) produce r-process elements after a time-delayed inspiral process. Once a significant number of NSMs are present in a galaxy, r-process elements, such as Eu, are expected to significantly increase with time. Yet, there have been limited observational data in support of Eu increasing within Local Group galaxies. We have o…