Search Publications
Interpreting the Properties of Solar Energetic Particle Events by Using Combined Imaging and Modeling of Interplanetary Shocks
St. Cyr, O. C.; Szabo, A.; Rouillard, A. P. +10 more
Images of the solar corona obtained by the Solar-Terrestrial Relations Observatory (STEREO) provide high-cadence, high-resolution observations of a compression wave forming ahead of a fast (940 km s-1) coronal mass ejection (CME) that erupted at ~9:00 UT on 2010 April 03. The passage of this wave at 1 AU is detected in situ by the Advan…
AEGIS: The Morphologies of Green Galaxies at 0.4 < z < 1.2
Moustakas, John; Salim, Samir; Coil, Alison L. +3 more
We present quantitative morphologies of ~300 galaxies in the optically defined green valley at 0.4 < z < 1.2, in order to constrain the mechanism(s) responsible for quenching star formation in the bulk of this population. The sample is selected from galaxies in the All-Wavelength Extended Groth Strip International Survey (AEGIS). While the g…
Are C60 Molecules Detectable in Circumstellar Shells of R Coronae Borealis Stars?
Lambert, D. L.; García-Hernández, D. A.; Kameswara Rao, N.
The hydrogen-poor, helium-rich, and carbon-rich character of the gas around R Coronae Borealis (RCB) stars has been suggested to be a site for formation of C60 molecules. This suggestion is not supported by observations reported here showing that infrared transitions of C60 are not seen in a large sample of RCB stars observed…
Supermassive Black Hole Growth in Starburst Galaxies over Cosmic Time: Constraints from the Deepest Chandra Fields
Lehmer, B. D.; Alexander, D. M.; Papovich, C. +5 more
We present an analysis of deep multiwavelength data for z ≈ 0.3-3 starburst galaxies selected by their 70 µm emission in the Extended-Chandra Deep Field-South and Extended Groth Strip. We identify active galactic nuclei (AGNs) in these infrared sources through their X-ray emission and quantify the fraction that host an AGN. We find that the …
Evidence for an FU Orionis-like Outburst from a Classical T Tauri Star
Filippenko, Alexei V.; Cenko, S. Bradley; Law, Nicholas M. +28 more
We present pre- and post-outburst observations of the new FU Orionis-like young stellar object PTF 10qpf (also known as LkHα 188-G4 and HBC 722). Prior to this outburst, LkHα 188-G4 was classified as a classical T Tauri star (CTTS) on the basis of its optical emission-line spectrum superposed on a K8-type photosphere and its photometric variabilit…
Using Hα Morphology and Surface Brightness Fluctuations to Age-date Star Clusters in M83
Mutchler, Max; McCarthy, Patrick J.; Calzetti, Daniela +22 more
We use new WFC3 observations of the nearby grand-design spiral galaxy M83 to develop two independent methods for estimating the ages of young star clusters. The first method uses the physical extent and morphology of Hα emission to estimate the ages of clusters younger than τ ≈ 10 Myr. It is based on the simple premise that the gas in very young (…
MUSTANG High Angular Resolution Sunyaev-Zel'dovich Effect Imaging of Substructure in Four Galaxy Clusters
Sun, M.; Sarazin, C. L.; Devlin, M. J. +6 more
We present resolved images of four massive clusters of galaxies through the Sunyaev-Zel'dovich effect (SZE). These measurements, made at 90 GHz with the MUSTANG receiver on the Green Bank Telescope (GBT), reveal pressure substructure to the intracluster medium (ICM) in three of the four systems. The SZE and X-ray morphology of MACS0744.8+3927 are …
The Spectroscopic Signature of Quasi-periodic Upflows in Active Region Timeseries
De Pontieu, Bart; McIntosh, Scott W.; Tian, Hui
Quasi-periodic propagating disturbances are frequently observed in coronal intensity image sequences. These disturbances have historically been interpreted as being the signature of slow-mode magnetoacoustic waves propagating into the corona. The detailed analysis of Hinode EUV Imaging Spectrometer (EIS) timeseries observations of an active region…
Studying Extreme Ultraviolet Wave Transients with a Digital Laboratory: Direct Comparison of Extreme Ultraviolet Wave Observations to Global Magnetohydrodynamic Simulations
Lugaz, Noé; Downs, Cooper; Roussev, Ilia I. +3 more
In this work, we describe our effort to explore the signatures of large-scale extreme ultraviolet (EUV) transients in the solar corona (EUV waves) using a three-dimensional thermodynamic magnetohydrodynamic model. We conduct multiple simulations of the 2008 March 25 EUV wave (~18:40 UT), observed both on and off of the solar disk by the STEREO-A a…
Off-limb Solar Coronal Wavefronts from SDO/AIA Extreme-ultraviolet Observations—Implications for Particle Production
Schwadron, N. A.; Korreck, K. E.; Lobzin, V. V. +2 more
We derive kinematic properties for two recent solar coronal transient waves observed off the western solar limb with the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) mission. The two waves occurred over ~10 minute intervals on consecutive days—2010 June 12 and 13. For the first time, off-limb waves are imaged wi…