Search Publications
M Dwarfs from Hubble Space Telescope Star Counts. V. The I-Band Luminosity Function
Gould, Andrew; Salim, Samir; Bahcall, John N. +2 more
We derive the disk I-band luminosity function from the Zheng et al. sample of ~1400 disk M dwarfs observed with the Hubble Space Telescope. We adopt a Galactic-height-dependent color-magnitude relation to account for the metallicity gradient above the Galactic plane. The resultant I-band luminosity function peaks at MI~9.5 and drops sha…
An Ion-Cyclotron Resonance-driven Three-Fluid Model of the Slow Wind near the Sun
Chen, Y.; Li, X.
A three-fluid slow wind consisting of electrons, protons, and O+5 ions is constructed to account for a recent UVCS/SOHO observation. In this model, ion-cyclotron waves, which are assumed to be generated by a Kolmogorov turbulent cascade, are assumed to play a key role in driving the slow solar wind. By reproducing recent measurements on…
A New Unidentified Far-Infrared Band in NGC 7027
Cernicharo, José; Goicoechea, Javier R.; Masso, Helena +1 more
We report on the detection of a molecular band centered at ~98 µm (~102 cm-1), observed with the Infrared Space Observatory in the young planetary nebula NGC 7027. The band structure and intensity cannot be reproduced by atomic fine-structure lines, recombination lines, or the rotational emission of abundant molecules. We discuss …
A Mid-Infrared Survey of L1641N with ISOCAM
Noriega-Crespo, Alberto; Ali, Babar
We present the results from our analysis of the Infrared Space Observatory (ISO) data on the L1641N outflow region located in the Orion A molecular cloud. The data were obtained with the array camera (ISOCAM) using two broadband filters, LW2 (6.7 µm) and LW3 (14 µm), and the narrowband circular variable filter (CVF), which provides low…
Limits on I-Band Microvariability of the Galactic Bulge Mira Variables
McGowan, K. E.; Vestrand, W. T.; Woźniak, P. R.
We search for microvariability in a sample of 485 Mira variables with high-quality I-band light curves from the second-generation Optical Gravitational Lensing Experiment (OGLE-II). Rapid variations with amplitudes in the ~0.2-1.1 mag range lasting hours to days were discovered in Hipparcos data by de Laverny et al. Our search is primarily sensiti…
A Hubble Space Telescope STIS Observation of VW Hydri at the Exact Far-Ultraviolet Onset of an Outburst
Szkody, Paula; Sion, Edward M.; Gänsicke, Boris T. +1 more
We present an analysis of Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph data of VW Hyi that we acquired 14 days after a superoutburst. At the time of our observation, the system appears to be going into outburst with the longest wavelengths increasing in flux by a factor of 5 while the shortest wavelengths increase by only a fa…
Spectrum of Solar Type I Continuum Noise Storm in the 50-80 MHz Band and Plasma Characteristics in the Associated Source Region
Sundaram, G. A. Shanmugha; Subramanian, K. R.
Continuum observations of a solar noise storm in the frequency range of 50-80 MHz observed with the Gauribidanur radio spectrograph during 2000 September 26 and 27 are presented here. The radio spectral index of the noise storm continuum in the 50-80 MHz band is found to be ~3.65 during the above period. The noise storm continuum radiation is expl…
Comparing Chandra and SIRTF Observations for Obscured Starbursts and Active Galactic Nuclei at High Redshift
Zezas, A.; Charmandaris, V.; Weedman, D.
Tracking the star formation rate to high redshifts requires knowledge of the contribution from both optically visible and obscured sources. The dusty, optically obscured galaxies can be located by X-ray and infrared surveys. To establish criteria for selecting such sources based only on X-ray and infrared surveys, we determine the ratio of infrare…
Estimation of the Three-Dimensional Space Speed of a Coronal Mass Ejection Using Metric Radio Data
Ramesh, R.; Kathiravan, C.
We present an independent method for obtaining the three-dimensional space speed of a coronal mass ejection in the lower solar atmosphere through ray-tracing analysis of the thermal radio counterpart of its frontal loop in the metric wavelength range. The scheme was tested on the halo event observed on 1998 January 21, obtaining an estimated space…
Hubble Space Telescope Discovery of an Optical Counterpart to the Supersoft X-Ray Source in the Globular Cluster M3
Heinke, Craig O.; Kahabka, Peter; Edmonds, Peter D.
We report the detection with the Hubble Space Telescope of an optical counterpart to the transient supersoft X-ray source 1E 1339.8+2837 in the globular cluster M3. The counterpart is found near the faint end of the subgiant branch in the V versus V-I color-magnitude diagram but is extremely bright in the U band. Variability is detected over a ran…