Search Publications
Mid-Infrared Emission from E+A Galaxies in the Coma Cluster
Rieke, G. H.; Quillen, A. C.; Rieke, M. J. +2 more
We have used ISO to observe at 12 µm seven E+A galaxies plus an additional emission-line galaxy, all in the Coma Cluster. E+A galaxies lacking narrow emission lines have 2.2-12 µm flux density ratios or limits similar to old stellar populations (typical of early-type galaxies). Only galaxies with emission lines have enhanced 12 µ…
The Struve-Sahade Effect: A Tale of Three Stars
Gies, Douglas R.; Riddle, Reed; Penny, Laura R. +1 more
The ``Struve-Sahade effect'' (S-S effect) is the apparent weakness of lines of the secondary in massive binaries when the secondary is receding. This effect poses problems for the accurate reconstruction of the separated primary and secondary spectra. We have reexamined IUE spectra of three classical, hot binaries studied by D. Stickland in 1997. …
Mid-Infrared Images of Luminous Infrared Galaxies in a Merging Sequence
Gao, Yu; Gruendl, Robert A.; Hwang, Chorng-Yuan +2 more
We report mid-infrared observations of several luminous infrared galaxies (LIGs) carried out with the Infrared Space Observatory. Our sample was chosen to represent different phases of a merger sequence of galaxy-galaxy interaction with special emphasis on early/intermediate stages of merging. The mid-infrared emission of these LIGs shows extended…
Star Counts and the Warped and Flaring Milky Way Disk
Evans, N. Wyn; Flynn, Chris; Gyuk, Geza
This paper reports the star count predictions of warped and flaring models of the outer Milky Way disk. These have been suggested as possible locations of the lenses responsible for the microlensing events toward the Large Magellanic Cloud (LMC). Three such models are investigated in detail, and the theoretical predictions are confronted with Hubb…
Infrared Candidates for the Intense Galactic X-Ray Source GX 17+2
Anderson, Scott F.; Wachter, Stefanie; Margon, Bruce +2 more
We present new astrometric solutions and infrared Hubble Space Telescope observations of GX 17+2 (X1813-140), one of the brightest X-ray sources on the celestial sphere. Despite 30 years of intensive study and the existence of a strong radio counterpart with a subarcsecond position, the object remains optically unidentified. The observed X-ray cha…
Hubble Space Telescope Images and Spectra of the Remnant of SN 1885 in M31
Fesen, Robert A.; Hamilton, Andrew J. S.; Gerardy, Christopher L. +1 more
Near-UV Hubble Space Telescope images of the remnant of SN 1885 (S And) in M31 show a 0.70"+/-0.05" diameter absorption disk silhouetted against M31's central bulge, at SN 1885's historically reported position. The disk's size corresponds to a linear diameter of 2.5+/-0.4 pc at a distance of 725+/-70 kpc, implying an average expansion velocity of …
A Path Integral Approach to the Theory of Heliospheric Cosmic-Ray Modulation
Zhang, Ming
This paper introduces the path integral method, which has been widely used in quantum mechanics and statistical mechanics, into the field of cosmic-ray modulation theory to solve the Fokker-Planck equation for cosmic-ray transport. The path integral approach recognizes that the motion of cosmic rays is a Markov stochastic process. The derivation o…
The Radio Emission of the Seyfert Galaxy NGC 7319
Yoshida, Michitoshi; Wilson, Andrew S.; Aoki, Kentaro +1 more
We present VLA maps of the Seyfert 2 galaxy NGC 7319 at 3.6, 6, and 20 cm. Subarcsecond resolution is achieved at 3.6 and 6 cm. The radio emission exhibits a triple structure on a scale of ~4" (1.7 kpc). All three components have steep spectra, consistent with synchrotron radiation. We have also analyzed an HST archival, broad-band red image, whic…
First Direct Measurement of Acceleration in the Outflow of a Nova: U Scorpii (1999)
Livio, Mario; Lépine, Sébastien; Shara, Michael M. +1 more
We report the first direct measurement of acceleration in the outflow of a nova, U Sco, observed 5 days after the start of an outburst. Spectroscopic time series of the intense Hα emission line, obtained with the Space Telescope Imaging Spectrograph camera on board the Hubble Space Telescope, shows a bright emission component moving across the spe…
In Search of Emerging Magnetic Flux underneath the Solar Surface with Acoustic Imaging
Chang, Hsiang-Kuang; Chou, Dean-Yi; Sun, Ming-Tsung
With the method of acoustic imaging in helioseismology, we study an emerging flux region, NOAA 7978, using data taken with instruments of the Taiwan Oscillation Network (TON) and the Michelson Doppler Imager (MDI). Phase-shift maps of NOAA 7978 focusing at different depths are constructed, which show the evolution of emerging magnetic flux. Althou…