Search Publications
Cosmic Ray Transport in Heliospheric Magnetic Structures. I. Modeling Background Solar Wind Using the CRONOS Magnetohydrodynamic Code
Fichtner, H.; Heber, B.; Kühl, P. +4 more
The transport of energetic particles such as cosmic rays is governed by the properties of the plasma being traversed. While these properties are rather poorly known for galactic and interstellar plasmas due to the lack of in situ measurements, the heliospheric plasma environment has been probed by spacecraft for decades and provides a unique oppor…
Gas Bulk Motion in the Perseus Cluster Measured with Suzaku
Fukazawa, Y.; Tamura, T.; Iizuka, R. +8 more
We present the results from Suzaku observations of the Perseus Cluster, which is relatively close, the brightest in the X-ray sky, and a relaxed object with a cool core. A number of exposures of central regions and offset pointing with the X-ray Imaging Spectrometer cover a region within radii of 20'-30'. The central data are used to evaluate the …
The Secret Lives of Cepheids: Evolutionary Changes and Pulsation-induced Shock Heating in the Prototype Classical Cepheid δ Cep
Harper, Graham M.; Guinan, Edward F.; Engle, Scott G. +2 more
Over the past decade, the Secret Lives of Cepheids (SLiC) program has been carried out at Villanova University to study aspects and behaviors of classical Cepheids that are still not well understood. In this, the first of several planned papers on program Cepheids, we report the current results for δ Cep, the Cepheid prototype. Ongoing photometry …
Suzaku Studies of the Central Engine in the Typical Type I Seyfert NGC 3227: Detection of Multiple Primary X-Ray Continua with Distinct Properties
Makishima, Kazuo; Nakazawa, Kazuhiro; Yamada, Shin'ya +3 more
The type I Seyfert galaxy NGC 3227 was observed by Suzaku six times in 2008, with intervals of ~1 week and net exposures of ~50 ks each. Among the six observations, the source varied by nearly an order of magnitude; it was brightest in the first observation with a 2-10 keV luminosity of 1.2 × 1042 erg s-1, while faintest in t…
A Comparison of the Morphological Properties between Local and z ~ 1 Infrared Luminous Galaxies: Are Local and High-z (U)LIRGs Different?
Casey, Caitlin M.; Kartaltepe, Jeyhan S.; Sanders, D. B. +9 more
Ultraluminous and luminous infrared galaxies (ULIRGs and LIRGs) are the most extreme star-forming galaxies in the universe and dominate the total star formation rate density at z > 1. In the local universe (z < 0.3), the majority of ULIRGs and a significant portion of LIRGs are triggered by interactions between gas-rich spiral galaxies, yet …
New Insights on the Formation and Assembly of M83 from Deep Near-infrared Imaging
Calzetti, Daniela; Chandar, Rupali; Dalcanton, Julianne J. +5 more
We present results from new near-infrared (NIR) imaging from the Spitzer Space Telescope that trace the low surface brightness features of the outer disk and stellar stream in the nearby spiral galaxy, M83. Previous observations have shown that M83 hosts a faint stellar stream to the northwest and a star-forming disk that extends to ~3 times the o…
Spatially Resolved Imaging of the Two-component η Crv Debris Disk with Herschel
Pinte, C.; Duchêne, G.; Clampin, M. +13 more
We present far-infrared and submillimeter images of the η Crv debris disk system obtained with Herschel and SCUBA-2, as well as Hubble Space Telescope visible and near-infrared coronagraphic images. In the 70 µm Herschel image, we clearly separate the thermal emission from the warm and cold belts in the system, find no evidence for a putativ…
Hubble Space Telescope Emission Line Galaxies at z ~ 2: The Lyα Escape Fraction
Schneider, Donald P.; Blanc, Guillermo A.; Gronwall, Caryl +8 more
We compare the Hβ line strengths of 1.90 < z < 2.35 star-forming galaxies observed with the near-IR grism of the Hubble Space Telescope with ground-based measurements of Lyα from the HETDEX Pilot Survey and narrow-band imaging. By examining the line ratios of 73 galaxies, we show that most star-forming systems at this epoch have a Lyα escape…
A Search for Companions to Brown Dwarfs in the Taurus and Chamaeleon Star-Forming Regions
Todorov, K. O.; Luhman, K. L.; Konopacky, Q. M. +5 more
We have used WFPC2 on board the Hubble Space Telescope to obtain images of 47 members of the Taurus and Chamaeleon I star-forming regions that have spectral types of M6-L0 (M ~ 0.01-0.1 M ⊙). An additional late-type member of Taurus, FU Tau (M7.25+M9.25), was also observed with adaptive optics at Keck Observatory. In these images, we ha…
Observational Studies on the Near-infrared Unidentified Emission Bands in Galactic H II Regions
Onaka, Takashi; Sakon, Itsuki; Shimonishi, Takashi +4 more
Using a large collection of near-infrared spectra (2.5-5.4 µm) of Galactic H II regions and H II region-like objects, we perform a systematic investigation of astronomical polycyclic aromatic hydrocarbon (PAH) features. Thirty-six objects were observed using the infrared camera on board the AKARI satellite as a part of a director's time prog…