Search Publications
PEARLS: Low Stellar Density Galaxies in the El Gordo Cluster Observed with JWST
Grogin, Norman A.; Koekemoer, Anton M.; Pirzkal, Nor +23 more
A full understanding of how unusually large ultradiffuse galaxies (UDGs) fit into our conventional theory of galaxy formation remains elusive, despite the large number of objects identified locally. A natural extension of UDG research is the study of similar galaxies at higher redshift to establish how their properties may evolve over time. Howeve…
A 2:1 Mean-motion Resonance Super-Jovian Pair Revealed by TESS, FEROS, and HARPS
Trifonov, Trifon; Henning, Thomas; Latham, David W. +24 more
We report the discovery of a super-Jovian 2:1 mean-motion resonance (MMR) pair around the G-type star TIC 279401253, whose dynamical architecture is a prospective benchmark for planet formation and orbital evolution analysis. The system was discovered thanks to a single-transit event recorded by the Transiting Exoplanet Survey Satellite mission, w…
Examining the Rotation Period Distribution of the 40 Myr Tucana-Horologium Association with TESS
Kiman, Rocio; Faherty, Jacqueline K.; Gagné, Jonathan +6 more
The Tucana-Horologium association (Tuc-Hor) is a 40 Myr old moving group in the southern sky. In this work, we measure the rotation periods of 313 Tuc-Hor objects with TESS light curves derived from TESS full-frame images and membership lists driven by Gaia EDR3 kinematics and known youth indicators. We recover a period for 81.4% of the sample and…
Reconstructing the genesis of a globular cluster system at a look-back time of 9.1 Gyr with the JWST
Forbes, Duncan A.; Romanowsky, Aaron J.
Using early-release data from the JWST, Mowla et al. and Claeyssens et al. recently measured various properties for gravitationally lensed compact sources ('sparkles') around the 'Sparkler' galaxy at a redshift of 1.378 (a look-back time of 9.1 Gyr). Here, we focus on the Mowla et al. as they were able to break the age-metallicity degeneracy and d…
Strong and Rapid X-Ray Variability of the Super-Eddington Accreting Quasar SDSS J081456.10+532533.5
Brandt, W. N.; Garmire, Gordon P.; Luo, Bin +6 more
We report strong and rapid X-ray variability found from the super-Eddington accreting quasar SDSS J081456.10+532533.5 at z = 0.1197. It has a black hole mass of 2.7 × 107 M ⊙ and a dimensionless accretion rate of ≈4 measured from reverberation-mapping observations. It showed weak X-ray emission in the 2021 February Chandra ob…
Denoising Diffusion Probabilistic Models to Predict the Density of Molecular Clouds
Xu, Duo; Tan, Jonathan C.; Hsu, Chia-Jung +1 more
We introduce the state-of-the-art deep-learning denoising diffusion probabilistic model as a method to infer the volume or number density of giant molecular clouds (GMCs) from projected mass surface density maps. We adopt magnetohydrodynamic simulations with different global magnetic field strengths and large-scale dynamics, i.e., noncolliding and…
Time series analysis of bright TESS RRc stars: additional modes, phase variations, and more
Pál, A.; Plachy, E.; Molnár, L. +3 more
Using two years of data from the TESS space telescope, we have investigated the time series of 633 overtone pulsating field RR Lyrae (RRc) stars. The majority of stars (82.8 per cent) contain additional frequencies beyond the main pulsation. In addition to the frequencies previously explained by the ℓ = 8 and 9 non-radial modes, we have identified…
Photometric Calibrations of M-dwarf Metallicity with Markov Chain Monte Carlo and Bayesian Inference
Caballero, J. A.; Montes, D.; Duque-Arribas, C. +3 more
Knowledge of stellar atmospheric parameters (T eff, $\mathrm{log}g$ , [Fe/H]) of M dwarfs can be used to constrain both theoretical stellar models and Galactic chemical evolutionary models, and guide exoplanet searches, but their determination is difficult due to the complexity of the spectra of their cool atmospheres. In our ongoing ef…
X-ray and optical spectroscopic study of a γ Cassiopeiae analog source π Aquarii
Tsujimoto, Masahiro; Hayashi, Takayuki; Morihana, Kumiko +1 more
γ Cas analog sources are a subset of Be stars that emit intense and hard X-ray emission. Two competing ideas for their X-ray production mechanism are (a) the magnetic activities of the Be star and its disk and (b) the accretion from the Be star to an unidentified compact object. Among such sources, π Aqr plays a pivotal role as it is one of the on…
The X-Ray Binary-star Cluster Connection in Late-type Galaxies
Chandar, Rupali; Maccarone, Thomas J.; Thilker, David A. +3 more
We conduct one of the largest systematic investigations of bright X-ray binaries (XRBs) in both young star clusters and ancient globular clusters (GCs) using a sample of six nearby star-forming galaxies. Combining complete CXO X-ray source catalogs with optical Physics at High Angular Resolution in Nearby Galaxies-Hubble Space Telescope cluster ca…