Search Publications
Observations of asymmetric velocity fields and gas cooling in the NGC 4636 galaxy group X-ray halo
Kaastra, Jelle; Finoguenov, Alexis; Fabian, Andrew +4 more
Aims: This study aims to probe the thermodynamic properties of the hot intragroup medium (IGM) plasma in the core regions of the NGC 4636 galaxy group by detailed measurements of several emission lines and their relative intensities.
Methods: We analyzed deep XMM-Newton Reflection Grating Spectrometer (RGS) data in five adjacent spectral…
Compact E+A Galaxies as a Progenitor of Massive Compact Quiescent Galaxies at 0.2 < z < 0.8
Hwang, Ho Seong; Geller, Margaret J.; Damjanov, Ivana +5 more
We search the Sloan Digital Sky Survey and the Baryon Oscillation Sky Survey to identify ∼5500 massive compact quiescent galaxy candidates at 0.2 < z < 0.8. We robustly classify a subsample of 438 E+A galaxies based on their spectral properties and make this catalog publicly available. We examine sizes, stellar population ages, and kinematic…
Symbiotic Stars in X-Rays. III. Suzaku Observations
Nuñez, N. E.; Nelson, T.; Mukai, K. +2 more
We describe the X-ray emission as observed by Suzaku from five symbiotic stars that we selected for deep Suzaku observations after their initial detection with ROSAT, ASCA, and Swift. We find that the X-ray spectra of all five sources can be adequately fit with absorbed optically thin thermal plasma models, with either single- or multi-temperature…
The utility of polarized heliospheric imaging for space weather monitoring
Webb, D. F.; Davies, J. A.; DeForest, C. E. +1 more
A polarizing heliospheric imager is a critical next generation tool for space weather monitoring and prediction. Heliospheric imagers can track coronal mass ejections (CMEs) as they cross the solar system, using sunlight scattered by electrons in the CME. This tracking has been demonstrated to improve the forecasting of impact probability and arri…
Accretion disc/corona emission from a radio-loud narrow-line Seyfert 1 galaxy PKS 0558-504
Dewangan, G. C.; Ghosh, R.; Raychaudhuri, B.
Approximately 10-20 per cent of active galactic nuclei (AGN) are known to eject powerful jets from the innermost regions. There is very little observational evidence if the jets are powered by spinning black holes and if the accretion discs extend to the innermost regions in radio-loud AGN. Here, we study the soft X-ray excess, the hard X-ray spec…
Comparing Dark Energy Survey and HST-CLASH observations of the galaxy cluster RXC J2248.7-4431: implications for stellar mass versus dark matter
Benoit-Lévy, A.; D'Andrea, C. B.; Abbott, T. M. C. +66 more
We derive the stellar mass fraction in the galaxy cluster RXC J2248.7-4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (five filters) with those from the Hubble Space Telescope Cluster Lensing And Supernova Survey (CLASH; 17 filters). When the cluster spectroscopic…
Spatial dimensions of the electron diffusion region in anti-parallel magnetic reconnection
Nakamura, Rumi; Nakamura, Takuma; Haseagwa, Hiroshi
Spatial dimensions of the detailed structures of the electron diffusion region in anti-parallel magnetic reconnection were analyzed based on two-dimensional fully kinetic particle-in-cell simulations. The electron diffusion region in this study is defined as the region where the positive reconnection electric field is sustained by the electron ine…
UV Spectroscopy of Star-grazing Comets Within the 49 Ceti Debris Disk
Roberge, Aki; Miles, Brittany E.; Welsh, Barry
We present the analysis of time-variable Doppler-shifted absorption features in far-UV spectra of the unusual 49 Ceti debris disk. This nearly edge-on disk is one of the brightest known and is one of the very few containing detectable amounts of circumstellar (CS) gas as well as dust. In our two visits of Hubble Space Telescope STIS spectra, varia…
The Prevalence and Impact of Wolf-Rayet Stars in Emerging Massive Star Clusters
Massey, Philip; Johnson, Kelsey E.; Indebetouw, Rémy +1 more
We investigate Wolf-Rayet (WR) stars as a source of feedback contributing to the removal of natal material in the early evolution of massive star clusters. Despite previous work suggesting that massive star clusters clear out their natal material before the massive stars evolve into the WR phase, WR stars have been detected in several emerging mas…
A comprehensive analysis of ion cyclotron waves in the equatorial magnetosphere of Saturn
Simon, Sven; Kabanovic, Slawa; Meeks, Zachary
We present a comprehensive analysis of ion cyclotron waves in the equatorial magnetosphere of Saturn, considering all magnetic field data collected during the Cassini era (totaling to over 4 years of data from the equatorial plane). This dataset includes eight targeted flybys of Enceladus, three targeted flybys of Dione, and three targeted flybys …