Search Publications
The Energy Conversion Rate of an Active Region Transient Brightening Estimated by Hinode Spectroscopic Observations
Imada, Shinsuke; Kawai, Toshiki
We statistically estimate the conversion rate of the energy released during an active region transient brightening to Doppler motion and thermal and nonthermal energies. We used two types of data sets for the energy estimation and detection of transient brightenings. One includes spectroscopic images of Fe XIV, Fe XV, and Fe XVI lines observed by …
Photometric Variability of the Pre-main-sequence Stars toward the Sh 2-190 Region
Matsunaga, N.; Sharma, Saurabh; Panwar, Neelam +7 more
We present the results from our time-series imaging data taken with the 1.3 m Devasthal fast optical telescope and 0.81 m Tenagara telescope in V, Rc, and Ic bands covering an area of ~18'4 × 18'4 toward the star-forming region Sh 2-190. This photometric data helped us to explore the nature of the variability of pre-main-sequ…
Exploration of the Origin of Galactic and Extragalactic Star Clusters through Simulated H-R Diagrams
Chattopadhyay, Tanuka; Mondal, Sreerup; Paul, Suman +2 more
The present work explores the origin of the formation of star clusters in our Galaxy and in the Small Magellanic Cloud (SMC) through simulated H-R diagrams and compare those with observed star clusters. The simulation study produces synthetic H-R diagrams through the Markov Chain Monte Carlo (MCMC) technique using the star formation history (SFH),…
Probing Polarization and the Role of Magnetic Fields in Cloud Destruction in the Keyhole Nebula
Dowell, C. Darren; Majumdar, Liton; Goldsmith, Paul F. +2 more
We present polarimetric observations of the Keyhole Nebula in the Carina Nebula Complex carried out using the Stratospheric Observatory for Infrared Astronomy. The Keyhole Nebula, located to the west of η Carinae, is believed to be disturbed by the stellar winds from the massive star. We observed the Keyhole Nebula at 89 µm wavelength with t…
On the Connection between Solar Surface Magnetic Flux and the Total Solar Irradiance
Gopalswamy, N.; Tessema, S. B.; Shukure, N. T.
Solar surface magnetic flux evolution plays a dominant role in the variability of total solar irradiance (TSI). Different proxies of magnetic activity have been introduced to correlate solar variability and TSI. We present the daily strong flux densities (SFDs) and weak flux densities (WFDs) defined with three magnetic thresholds calculated from t…
Connecting Atmospheric Properties and Synthetic Emission of Shock Waves Using 3D RMHD Simulations of the Quiet Sun
Kosovichev, Alexander G.; Sadykov, Viacheslav M.; Kitiashvili, Irina N. +1 more
We analyze the evolution of shock waves in high-resolution 3D radiative MHD simulations of the quiet Sun and their synthetic emission characteristics. The simulations model the dynamics of a 12.8 × 12.8 × 15.2 Mm quiet-Sun region (including a 5.2 Mm layer of the upper convection zone and a 10 Mm atmosphere from the photosphere to corona) with an i…
Dissecting the Strong-lensing Galaxy Cluster MS 0440.5+0204. II. New Optical Spectroscopic Observations in a Wider Area and Cluster Dynamical State
Limousin, Marceau; Carrasco, Eleazar R.; Ellingson, E. +5 more
We present an optical study of the strong-lensing galaxy cluster MS 0440.5+0204 at z = 0.19593, based on CFHT/MegaCam g', r' photometry and GMOS/Gemini and CFHT/MOS/SIS spectroscopy in a broader area than previous works. We have determined new spectroscopic redshifts for the most prominent gravitational arcs surrounding the central galaxy in the c…
The Occurrence-weighted Median Planets Discovered by Transit Surveys Orbiting Solar-type Stars and Their Implications for Planet Formation and Evolution
Schlaufman, Kevin C.; Halpern, Noah D.
Since planet occurrence and primordial atmospheric retention probability increase with period, the occurrence-weighted median planets discovered by transit surveys may bear little resemblance to the low-occurrence, short-period planets sculpted by atmospheric escape ordinarily used to calibrate mass-radius relations and planet formation models. An…
The Unusual Weak-line Quasar PG1407+265 and Its Foreground z 0.7 X-Ray Cluster
McDowell, Jonathan C.; Gallo, Luigi C.; Siemiginowska, Aneta +2 more
We present new observations of the odd z = 0.96 weak-line quasar PG1407+265, and report the discovery of CXOU J140927.9+261813, a z = 0.68 X-ray cluster. Archival X-ray photometry spanning nearly four decades reveals that PG1407+265 is variable at the 1 dex level on a timescale of years. V-band variability is observed with an amplitude less than 0…
The Evolution of the Luminosity Function for Luminous Compact Blue Galaxies to z = 1
Pisano, D. J.; Bershady, M. A.; Crawford, S. M. +2 more
Luminous compact blue galaxies (LCBGs) are compact, star-forming galaxies that are rarely observed in the local universe but abundant at z = 1. This increase in LCBG number density over cosmic lookback time roughly follows the increase in the star formation rate density of the universe over the same period. We use publicly available data in the CO…