Search Publications
The Binary Fraction in the Globular Cluster M10 (NGC 6254): Comparing Core and Outer Regions
Dalessandro, E.; Beccari, G.; Ferraro, F. R. +3 more
We study the binary fraction of the globular cluster M10 (NGC 6254) as a function of the radius from the cluster core to the outskirts, by means of a quantitative analysis of the color distribution of stars relative to the fiducial main sequence. By taking advantage of two data sets, acquired with the Advanced Camera for Survey and the Wide Field …
H II Region Luminosity Function of the Interacting Galaxy M51
Hwang, Narae; Lee, Myung Gyoon; Lee, Jong Hwan
We present a study of H II regions in M51 using the Hubble Space Telescope Advanced Camera for Surveys images taken as part of the Hubble Heritage Program. We have cataloged about 19,600 H II regions in M51 with Hα luminosity in the range of L = 1035.5-1039.0 erg s-1. The Hα luminosity function of H II regions (H I…
Hubble Space Telescope/Advanced Camera for Surveys Observations of Europa's Atmospheric Ultraviolet Emission at Eastern Elongation
Nimmo, Francis; Saur, Joachim; Roth, Lorenz +7 more
We report results of a Hubble Space Telescope (HST) campaign with the Advanced Camera for Surveys to observe Europa at eastern elongation, i.e., Europa's leading side, on 2008 June 29. With five consecutive HST orbits, we constrain Europa's atmospheric O I 1304 Å and O I 1356 Å emissions using the prism PR130L. The total emissions of both oxygen m…
Identification of Super- and Subcritical Regions in Shocks Driven by Coronal Mass Ejections
Bemporad, A.; Mancuso, S.
In this work, we focus on the analysis of a coronal mass ejection (CME) driven shock observed by the Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph Experiment. We show that white-light coronagraphic images can be employed to estimate the compression ratio X = ρ d /ρ u all along the front of CME-…
Obscured GOODS Active Galactic Nuclei and Their Host Galaxies at z < 1.25: The Slow Black Hole Growth Phase
Treister, E.; Koekemoer, A. M.; Grogin, N. A. +4 more
We compute black hole masses and bolometric luminosities for 87 obscured active galactic nuclei (AGNs) in the redshift range 0.25 <= z <= 1.25, selected from the GOODS deep multi-wavelength survey fields via their X-ray emission. We fit the optical images and obtain morphological parameters for the host galaxy, separating the galaxy from its…
Magnetic Field-line Lengths in Interplanetary Coronal Mass Ejections Inferred from Energetic Electron Events
Richardson, I. G.; Kahler, S. W.; Haggerty, D. K.
About one quarter of the observed interplanetary coronal mass ejections (ICMEs) are characterized by enhanced magnetic fields that smoothly rotate in direction over timescales of about 10-50 hr. These ICMEs have the appearance of magnetic flux ropes and are known as "magnetic clouds" (MCs). The total lengths of MC field lines can be determined usi…
Molecular Environment and an X-Ray Spectroscopy of Supernova Remnant Kesteven 78
Zhou, Ping; Chen, Yang
We investigate the molecular environment of the Galactic supernova remnant (SNR) Kesteven 78 and perform an XMM-Newton X-ray spectroscopic study for the northeastern edge of the remnant. SNR Kes 78 is found to interact with the molecular clouds (MCs) at a systemic local standard of rest velocity of 81 km s-1. At around this velocity, th…
The Far-ultraviolet "Continuum" in Protoplanetary Disk Systems. I. Electron-impact H2 and Accretion Shocks
France, Kevin; Yang, Hao; Linsky, Jeffrey L.
We present deep spectroscopic observations of the classical T Tauri stars DF Tau and V4046 Sgr in order to better characterize two important sources of far-ultraviolet continuum emission in protoplanetary disks. These new Hubble Space Telescope-Cosmic Origins Spectrograph observations reveal a combination of line and continuum emission from collis…
The Acoustic Cutoff Frequency of the Sun and the Solar Magnetic Activity Cycle
García, R. A.; Pallé, P. L.; Jiménez, A.
The acoustic cutoff frequency—the highest frequency for acoustic solar eigenmodes—is an important parameter of the solar atmosphere as it determines the upper boundary of the p-mode resonant cavities. At frequencies beyond this value, acoustic disturbances are no longer trapped but are traveling waves. Interference among them gives rise to higher-…
Chandra Observation of the TeV Source HESS J1834-087
Pavlov, George G.; Kargaltsev, Oleg; Misanovic, Zdenka
Chandra ACIS observed the field of the extended TeV source HESS J1834-087 for 47 ks. A previous XMM-Newton EPIC observation of the same field revealed a point-like source (XMMU J183435.3-084443) and an offset region of faint extended emission. In the low-resolution, binned EPIC images the two appear to be connected. However, the high-resolution Ch…