Search Publications
Roaring to Softly Whispering: X-Ray Emission after ∼3.7 yr at the Location of the Transient AT2018cow and Implications for Accretion-powered Scenarios
Berger, E.; Vignali, C.; Maccarone, T. +11 more
We present the first deep X-ray observations of luminous fast blue optical transient (LFBOT) AT 2018cow at ∼3.7 yr since discovery, together with the reanalysis of the observation at δ t ∼ 220 days. X-ray emission is significantly detected at a location consistent with AT 2018cow. The very soft X-ray spectrum and sustained luminosity are distinct …
Mining the GALAH Data. I. Study of Five Super Lithium-rich Metal-poor Giants
Reddy, Bacham E.; Susmitha, Antony; Mallick, Anohita
The presence of a large amount of Li in giants is still a mystery. Most of the super Li-rich (SLR) giants reported in recent studies are in the solar metallicity regime. Here, we study the five metal-poor SLRs from the Galactic Archeology with HERMES Data Release 3, with their [Fe/H] ranging from ‑1.35 to ‑2.38 with lithium abundance of A(Li) ≥ 3.…
Rotational Evolution of Classical T Tauri Stars: Models and Observations
Pinsonneault, Marc; Stassun, Keivan G.; Kounkel, Marina +17 more
We developed a grid of stellar rotation models for low-mass and solar-type classical T Tauri stars (CTTS; 0.3M ⊙ < M * < 1.2M ⊙). These models incorporate the star–disk interaction and magnetospheric ejections to investigate the evolution of the stellar rotation rate as a function of the mass of the star M
Ring Gap Structure around Class I Protostar WL 17
Shoshi, Ayumu; Harada, Naoto; Tokuda, Kazuki +7 more
WL 17 is a Class I object and was considered to have a ring–hole structure. We analyzed the structure around WL 17 to investigate the detailed properties of this object. We used Atacama Large Millimeter/submillimeter Array archival data, which have a higher angular resolution than previous observations. We investigated the WL 17 system with the 1.…
Fast Outflow in the Host Galaxy of the Luminous z = 7.5 Quasar J1007+2115
Shen, Yue; Fan, Xiaohui; Li, Mingyu +24 more
The James Webb Space Telescope opens a new window to directly probe luminous quasars powered by billion solar mass black holes in the Epoch of Reionization and their coevolution with massive galaxies with unprecedented details. In this paper, we report the first results from a deep NIRSpec integral field unit spectroscopic study of a quasar at z =…
Low-mass Galaxy Interactions Trigger Black Hole Activity
Nair, Preethi; Irwin, Jimmy A.; Mićić, Marko +3 more
The existence of high-z overmassive supermassive black holes represents a major conundrum in our understanding of black hole evolution. In this Letter, we probe from the observational point of view how early Universe environmental conditions could have acted as an evolutionary mechanism for the accelerated growth of the first black holes. Under th…
Parallel Diffusion Coefficient of Energetic Charged Particles in the Inner Heliosphere from the Turbulent Magnetic Fields Measured by Parker Solar Probe
Klein, Kristopher G.; Chen, Xiaohang; Giacalone, Joe +1 more
Diffusion coefficients of energetic charged particles in turbulent magnetic fields are a fundamental aspect of diffusive transport theory but remain incompletely understood. In this work, we use quasi-linear theory to evaluate the spatial variation of the parallel diffusion coefficient κ ∥ from the measured magnetic turbulence power spe…
Tracing the Origins of Mass Segregation in M35: Evidence for Primordially Segregated Binaries
von Hippel, Ted; Motherway, Erin; Geller, Aaron M. +2 more
M35 is a young open cluster and home to an extensive binary population. Using Gaia Data Release 3, Pan-STARRS, and Two Micron All Sky Survey photometry with the Bayesian statistical software, BASE-9, we derive precise cluster parameters, identify single and binary cluster members, and extract their masses. We identify 571 binaries down to Gaia G =…
The Effect of Starspots on Spectroscopic Age and Mass Estimates of Nonaccreting T Tauri Stars in the Taurus–Auriga Star-forming Region
Hillenbrand, Lynne A.; Markham, Madison; Bary, Jeffrey S. +1 more
Accurate age and mass determinations for young pre-main-sequence stars are made challenging by the presence of large-scale starspots. We present results from a near-infrared spectroscopic survey of 10 T-Tauri Stars in Taurus-Auriga that characterize spot-filling factors and temperatures, the resulting effects on temperature and luminosity determin…
The Orbit and Dynamical Mass of Polaris: Observations with the CHARA Array
Torres, Guillermo; Mérand, Antoine; Monnier, John D. +19 more
The 30 yr orbit of the Cepheid Polaris has been followed with observations by the Center for High Angular Resolution Astronomy (CHARA) Array from 2016 through 2021. An additional measurement has been made with speckle interferometry at the Apache Point Observatory. Detection of the companion is complicated by its comparative faintness—an extreme f…