Search Publications
Limits on the Optical Brightness of the ɛ Eridani Dust Ring
Calzetti, Daniela; Livio, Mario; Gull, Theodore R. +10 more
The STIS CCD camera on the Hubble Space Telescope (HST) was used to take deep optical images near the K2 V main-sequence star ɛ Eridani in an attempt to find an optical counterpart of the dust ring previously imaged by submillimeter observations. Upper limits for the optical brightness of the dust ring are determined and discussed in the context o…
The Enigmatic Radio Source T Tauri S
Hummel, C. A.; Thomasson, P.; Johnston, K. J. +4 more
We have observed the T Tau multiple star system using the Multielement Radio-linked Interferometer Network at a frequency of 5 GHz. The compact centimeter wavelength radio emission from T Tau S has been found to consist of at least two components separated by approximately 70 mas in right ascension at Julian epoch 2001.89. Using this data and that…
Submillimeter Emission from Type Ia Supernova Host Galaxies at z = 0.5
Farrah, D.; Fox, M.; Rowan-Robinson, M. +2 more
We present deep submillimeter observations of 17 galaxies at z=0.5 that are hosts of a Type Ia supernova. Two galaxies are detected directly, and the sample is detected statistically with a mean 850 µm flux of 1.01+/-0.33 mJy, which is 25%-135% higher than locally. We infer that the mean value of AV in normal galaxies at z=0.5 is …
The Relationship of the Chromosphere to the Lower Solar Transition Region
Doschek, G. A.; Mariska, J. T.; Akiyama, S.
We examine the intensity correlations among lower transition region emission lines of N III, N IV, N V, O II, O III, O IV, O V, S IV, and S V. We find strong intensity correlations, with 1 σ deviations in line intensity ratios less than about 35% on spatial scales of 1". For strong lines the percent deviations are significantly less than this. The…
The z~4 Lyman Break Galaxies: Colors and Theoretical Predictions
Papovich, Casey; Ferguson, Henry C.; Giavalisco, Mauro +4 more
We investigate several fundamental properties of z~4 Lyman break galaxies by comparing observations with the predictions of a semianalytic model based on the cold dark matter theory of hierarchical structure formation. We use a sample of B435-dropouts from the Great Observatories Origins Deep Survey and complement the Advanced Camera fo…
A Substellar Companion to van Maanen 2
Makarov, Valeri V.
The Hipparcos data for the nearest white dwarf van Maanen 2 (=HIP 3829; distance of 4.4 pc) indicate astrometric binarity, in that the proper motion has a large first derivative not accounted for as a perspective acceleration due to changing distance. The presence of a companion was suspected, but never demonstrated, from the pre-Hipparcos astrome…
X-Ray Line-emitting Objects in XMM-Newton Observations: The Tip of the Iceberg
Braito, V.; Caccianiga, A.; Severgnini, P. +2 more
We present preliminary results from a novel search for X-ray line-emitting objects (XLEOs) in XMM-Newton images. Three sources have been detected in a test-run analysis of 13 XMM-Newton observations. The three objects found are most likely extremely absorbed active galactic nuclei characterized by a column density NH~1024 cm<…
Hot Interstellar Gas and Stellar Energy Feedback in the Antennae Galaxies
Guerrero, Martín A.; Chu, You-Hua; Gruendl, Robert A. +3 more
We have analyzed Chandra archival observations of the Antennae galaxies to study the distribution and physical properties of its hot interstellar gas. Eleven distinct diffuse X-ray emission regions are selected according to their underlying interstellar structures and star formation activity. The X-ray spectra of these regions are used to determin…
Models for Solar Magnetic Loops. IV. On the Relation between Coronal and Footpoint Plasma in Active Region Loops
Landi, E.; Feldman, U.
In the present work we analyze several SUMER intensity maps of active region solar loops in order to compare the relative brightnesses of the footpoints and the coronal section of active region loops. We find that the former are barely distinguishable from the background emission of the active region, while the coronal emission of loops is confine…
Two New X-Ray/Optical/Radio Supernova Remnants in M31
Gelfand, Joseph D.; Williams, Benjamin F.; Kong, Albert K. H. +3 more
We compare a deep (37 ks) Chandra ACIS-S image of the M31 bulge to Local Group Survey narrowband optical data and Very Large Array (VLA) radio data of the same region. Our precisely registered images reveal two new optical shells with X-ray counterparts. These shells have sizes, [SII]/Hα flux ratios, and X-ray spectral properties typical of supern…