Search Publications
Variable Stars in M31 Stellar Clusters from the Panchromatic Hubble Andromeda Treasury
Williams, Benjamin F.; Johnson, L. Clifton; Girardi, Léo +9 more
Variable stars in stellar clusters can offer key constraints on stellar evolution and pulsation models, utilizing estimates of host cluster properties to constrain stellar physical parameters. We present a catalog of 86 luminous (F814W < 19) variable stars in M31 clusters identified by mining the archival Panchromatic Hubble Andromeda Treasury …
A Joint Microwave and Hard X-Ray Study toward Understanding the Transport of Accelerated Electrons During an Eruptive Solar Flare
Chen, Bin; Yu, Sijie; Battaglia, Andrea F. +1 more
The standard flare model, despite its success, is limited in comprehensively explaining the various processes involving nonthermal particles. One such missing ingredient is a detailed understanding of the various processes involved during the transport of accelerated electrons from their site of acceleration to different parts of the flare region.…
A Surprising Excess of Radio Emission in Extremely Stable Quasars: A Unique Clue to Jet Launching?
Cai, Zhen-Yi; Wang, Jun-Xian; Yuan, Feng +6 more
Quasars are generally divided into jetted radio-loud and nonjetted radio-quiet ones, but why only 10% of quasars are radio-loud has been puzzling for decades. Other than jet-induced phenomena, black hole mass, or Eddington ratio, a prominent difference between jetted and nonjetted quasars has scarcely been detected. Here we show a unique distincti…
An Extremely Low-density Exoplanet Spins Slow
Zhu, Wei; Cañas, Caleb I.; Bello-Arufe, Aaron +3 more
We present constraints on the shape of Kepler-51d, which is a superpuff with a mass ∼6 M ⊕ and a radius ∼9 R ⊕, based on detailed modeling of the transit light curve from James Webb Space Telescope (JWST) NIRSpec. The projected shape of this extremely low-density planet is consistent with being spherical, and a projected obla…
Origin of Line Broadening in Fading Granules: Influence of Small-scale Turbulence
Katsukawa, Yukio; Ishikawa, Ryohtaroh T.
In the quiet region of the solar photosphere, turbulent convective motions of the granular flows naturally drive the subgranular-scale flows. However, evaluating such small-scale velocities is challenging because of the limited instrumental resolution. Our previous study, R. T. Ishikawa et al., found line-broadening events during the fading proces…
Pulling Back the Curtain on Shocks and Star Formation in NGC 1266 with Gemini-NIFS
Heckman, Timothy; Aalto, Susanne; Ogle, Patrick +21 more
We present Gemini near-infrared integral field spectrograph K-band observations of the central 400 pc of NGC 1266, a nearby (D ≈ 30 Mpc) post-starburst galaxy with a powerful multiphase outflow and a shocked interstellar medium. We detect seven H2 rovibrational emission lines excited thermally to T ∼ 2000 K, and weak Brγ emission, consi…
Confirming the Tidal Tails of the Young Open Cluster Blanco 1 with TESS Rotation Periods
Huang, Chelsea X.; Bouma, Luke G.; Vanderburg, Andrew M. +1 more
Blanco 1 is an ≈130 Myr open cluster located 240 pc from the Sun, below the Galactic plane. Recent studies have reported the existence of diffuse tidal tails extending 50–60 pc from the cluster center based on the positions and velocities measured by Gaia. To independently assess the reality and extent of this structure, we used light curves gener…
Spectroscopic Study of Heating Distributions and Mechanisms Using Hinode/EIS
Hara, Hirohisa; Ishigami, Shun; Oba, Takayoshi
Heating distributions along coronal loops are obtained from spectroscopic data with the Hinode/EUV Imaging Spectrometer. The loop half-lengths L half are in the range of 24–107 Mm for our analysis of 18 loops. By using the analytical approximations to 1D hydrostatic numerical calculations of electron temperature T e (s) and …
Measuring 60 pc-scale Star Formation Rate of the Nearby Seyfert Galaxy NGC 1068 with ALMA, HST, VLT/MUSE, and VLA
Saito, Toshiki; Nakanishi, Kouichiro; Ikarashi, Soh +7 more
The star formation rate (SFR) is a fundamental parameter for describing galaxies and inferring their evolutionary course. H II regions yield the best measure of instantaneous SFR in galaxies, although the derived SFR can have large uncertainties depending on tracers and assumptions. We present an SFR calibration for the entire molecular gas disk o…
Using the Ca II Lines in T Tauri Stars to Infer the Abundance of Refractory Elements in the Innermost Disk Region
Herczeg, Gregory J.; Manara, Carlo F.; Venuti, Laura +5 more
We present a study of the abundance of calcium in the innermost disk of 70 T Tauri stars in the star-forming regions of Chamaeleon I, Lupus, and Orion OB1b. We use calcium as a proxy for the refractory material that reaches the inner disk. We used magnetospheric accretion models to analyze the Ca II emission lines and estimate abundances in the ac…