Search Publications
Ultraviolet and Chromospheric Activity and Habitability of M Stars
Huang, Yang; Liu, Jifeng; Wang, Song +4 more
M-type stars are crucial for stellar activity studies because they cover two types of magnetic dynamos and are particularly intriguing for habitability studies due to their abundance and long lifespans during the main-sequence stage. In this paper, we used the LAMOST DR9 catalog and the GALEX UV archive data to investigate the chromospheric and UV…
Determining Cosmological-model-independent H 0 with Gravitationally Lensed Supernova Refsdal
Li, Xiaolei; Liao, Kai
The reappearance of supernova Refsdal with detailed modeling of the lens cluster allows us to measure the time-delay distance, which serves as a powerful tool to determine the Hubble constant (H 0). We give a cosmological-model-independent method to estimate H 0 through Gaussian process regression, using time-delay measuremen…
Stellar Models are Reliable at Low Metallicity: An Asteroseismic Age for the Ancient Very Metal-poor Star KIC 8144907
Li, Yaguang; Huber, Daniel; Ong, J. M. Joel +15 more
Very-metal-poor stars ([Fe/H] < ‑2) are important laboratories for testing stellar models and reconstructing the formation history of our galaxy. Asteroseismology is a powerful tool to probe stellar interiors and measure ages, but few asteroseismic detections are known in very-metal-poor stars and none have allowed detailed modeling of oscillat…
Scylla. II. The Spatially Resolved Star Formation History of the Large Magellanic Cloud Reveals an Inverted Radial Age Gradient
McQuinn, Kristen B. W.; Dolphin, Andrew E.; Murray, Claire E. +11 more
The proximity of the Magellanic Clouds provides the opportunity to study interacting dwarf galaxies near a massive host, and spatial trends in their stellar population properties in particular, with a unique level of detail. The Scylla pure parallel program has obtained deep (80% complete to >1 mag below the ancient main-sequence turnoff), homo…
AT2018fyk: Candidate Tidal Disruption Event by a (Super)Massive Black Hole Binary
Wevers, T.; Li, D.; Kara, E. +8 more
The tidal disruption event (TDE) AT2018fyk has unusual X-ray, UV, and optical light curves that decay over the first ∼600 days, rebrighten, and decay again around 1200 days. We explain this behavior as a one-off TDE associated with a massive black hole (BH) binary. The sharp drop-offs from t ‑5/3 power laws at around 600 days naturally …
Chemical Diagnostics to Unveil Environments Enriched by First Stars
Cupani, Guido; D'Odorico, Valentina; Becker, George D. +2 more
Unveiling the chemical fingerprints of the first (Population III, hereafter Pop III) stars is crucial for indirectly studying their properties and probing their massive nature. In particular, very massive Pop III stars explode as energetic pair-instability supernovae (PISNe), allowing their chemical products to escape in the diffuse medium around …
Dracula's Chivito: Discovery of a Large Edge-on Protoplanetary Disk with Pan-STARRS
Drake, Jeremy J.; Bayyari, Ammar; Russell, Ray W. +6 more
We report the serendipitous discovery of a large edge-on protoplanetary disk in Pan-STARRS (PS1) images. PS1 has five broadband filters designated as g P1, r P1, i P1, z P1, and y P1 with mean wavelengths 4866, 6215, 7545, 8679, and 9633 Å, respectively. The disk's apparent size in the PS1 ima…
The Next Step in Galaxy Cluster Strong Lensing: Modeling the Surface Brightness of Multiply Imaged Sources
Acebron, Ana; Nonino, Mario; Grillo, Claudio +12 more
Overcoming both modeling and computational challenges, we present, for the first time, the extended surface-brightness distribution model of a strongly lensed source in a complex galaxy-cluster-scale system. We exploit the high-resolution Hubble Space Telescope (HST) imaging and extensive Multi Unit Spectroscopic Explorer spectroscopy to build an …
The Green Monster Hiding in Front of Cas A: JWST Reveals a Dense and Dusty Circumstellar Structure Pockmarked by Ejecta Interactions
Temim, Tea; Rest, Armin; Blair, William P. +27 more
JWST observations of the young Galactic supernova remnant Cassiopeia A revealed an unexpected structure seen as a green emission feature in colored composite MIRI F1130W and F1280W images—hence dubbed the Green Monster—that stretches across the central parts of the remnant in projection. Combining the kinematic information from NIRSpec and the MIR…
X-Ray and Multiwavelength Polarization of Mrk 501 from 2022 to 2023
Kaaret, Philip; Wu, Kinwah; Enoto, Teruaki +143 more
We present multiwavelength polarization measurements of the luminous blazar Mrk 501 over a 14 month period. The 2–8 keV X-ray polarization was measured with the Imaging X-ray Polarimetry Explorer (IXPE) with six 100 ks observations spanning from 2022 March to 2023 April. Each IXPE observation was accompanied by simultaneous X-ray data from NuSTAR,…