Search Publications
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…
Challenges in Forecasting the Evolution of a Distorted CME Observed During the First Close Solar Orbiter Perihelion
Telloni, Daniele; Liberatore, Alessandro; Vourlidas, Angelos +11 more
Coronal Mass Ejections (CMEs), drivers of the most severe Space Weather disturbances, are often assumed to evolve self-similarly during their propagation. However, open magnetic field structures in the corona, leading to higher-speed streams in the ambient solar wind, can be source of strong distortions of the CME front. In this paper, we investig…
Parkes Radio and NuSTAR X-Ray Observations of the Composite Supernova Remnant B0453–685 in the Large Magellanic Cloud
Acero, Fabio; Ballet, Jean; Kerr, Matthew +9 more
Gamma-ray emission is observed coincident in position to the evolved, composite supernova remnant (SNR) B0453–685. Prior multiwavelength investigations of the region indicate that the pulsar wind nebula (PWN) within the SNR is the most likely origin for the observed gamma rays, with a possible pulsar contribution that becomes significant at energi…
Kinematic Insights into Luminous Blue Variables and B[e] Supergiants
Oey, M. S.; Deman, Julian A.
Recent work suggests that many luminous blue variables (LBVs) and B[e] supergiants (sgB[e]) are isolated, implying that they may be products of massive binaries, kicked by partner supernovae. However, the evidence is somewhat complex and controversial. To test this scenario, we measure the proper-motion velocities for these objects in the LMC and …
The Kinematic and Chemical Properties of the Close-in Planet Host Star 8 UMi
Wang, Wei; Huang, Yang; Beers, Timothy C. +11 more
A recent study by Hon et al. reported that a close-in planet around the red clump star, 8 UMi, should have been engulfed during the expansion phase of its parent star's evolution. They explained the survival of this exoplanet through a binary-merger channel for 8 UMi. The key to testing this formation scenario is to derive the true age of this sta…