Search Publications
The Stellar Population and Star Clusters in the Unusual Local Group Galaxy IC 10
Hunter, Deidre A.
We present an analysis of Hubble Space Telescope U, V, I, and Hα images of the peculiar Local Group irregular galaxy IC 10. The images are used to determine the nature of the stellar products in a portion of the recent starburst in this galaxy. We identified 13 stellar associations and clusters, two of which are probably old (>=350 Myr) and the…
Multiwavelength Monitoring of the Narrow-Line Seyfert 1 Galaxy Arakelian 564. III. Optical Observations and the Optical-UV-X-Ray Connection
Filippenko, A. V.; Martini, P.; Turner, T. J. +36 more
We present the results of a 2 yr long optical monitoring program of the narrow-line Seyfert 1 galaxy Ark 564. The majority of this monitoring project was also covered by X-ray observations (RXTE), and for a period of ~50 days, we observed the galaxy in UV (HST) and X-rays (RXTE and ASCA) simultaneously with the ground-based observations. Rapid and…
NICMOS Observations of Low-Redshift Quasar Host Galaxies
McLeod, K. K.; McLeod, B. A.
We have obtained Near-Infrared Camera and Multi-Object Spectrometer images of 16 radio-quiet quasars observed as part of a project to investigate the ``luminosity/host-mass limit.'' The limit results were presented in a paper by McLeod, Rieke, & Storrie-Lombardi. In this paper, we present the images themselves, along with one- and two-dimensio…
Sustaining the Sun's Magnetic Network with Emerging Bipoles
Title, A. M.; Simon, G. W.; Weiss, N. O.
The Michelson Doppler Imager experiment on SOHO has revealed a ``magnetic carpet'' dominated by the emergence of bipolar magnetic flux in ephemeral active regions, which subsequently split into small flux elements that drift into the magnetic network. The effects of granular and supergranular convection on these flux elements are represented here …
A Short-Timescale Candidate Microlensing Event in the POINT-AGAPE Pixel Lensing Survey of M31
Giraud-Héraud, Y.; Evans, N. W.; Smartt, S. J. +14 more
We report the discovery of a short-duration microlensing candidate in the northern field of the POINT-AGAPE pixel lensing survey toward M31. Almost certainly, the source star has been identified on Hubble Space Telescope archival images, allowing us to infer an Einstein crossing time of tE=10.4 days, a maximum magnification of Amax…
Seismic Imaging of the Far Hemisphere of the Sun
Braun, D. C.; Lindsey, C.
We apply phase-sensitive helioseismic holography to Solar and Heliospheric Observatory/Michelson Dopper Imager data to demonstrate how acoustic travel-time perturbations may be mapped over the entire portion of the Sun facing away from the Earth, including the polar regions. In addition to offering significant improvements to ongoing space weather…
Multicolor Observations of the GRB 000926 Afterglow
Axelrod, T. S.; Price, P. A.; Harrison, F. A. +25 more
We present multicolor light curves of the optical afterglow of gamma-ray burst (GRB) 000926. Beginning ~1.5 days after the burst, the light curves of this GRB steepen measurably. The existence of such achromatic breaks is usually taken to be an important observational signature that the ejecta are not expanding isotropically but rather have a coll…
FUSE and Hubble Space Telescope/STIS Observations of Hot and Cold Gas in the AB Aurigae System
Deleuil, M.; Bouret, J. -C.; Roberge, A. +9 more
We present the first observations of a Herbig Ae star with a circumstellar disk by the Far-Ultraviolet Spectroscopic Explorer (FUSE) as well as a simultaneous observation of the star obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph (STIS). The spectra of AB Aurigae show emission and absorption features arising from gas…
Detection of an X-Ray Pulsar Wind Nebula and Tail in SNR N157B
Gotthelf, E. V.; Wang, Q. D.; Chu, Y. -H. +1 more
We report Chandra X-ray observations of the supernova remnant N157B in the Large Magellanic Cloud, which are presented together with an archival Hubble Space Telescope optical image and a radio continuum map for comparison. This remnant contains the recently discovered 16 ms X-ray pulsar PSR J0537-6910, the most rapidly rotating young pulsar known…
An Imaging and Spectroscopic Study of the zabs=3.38639 Damped Lyα System in Q0201+1120: Clues to Star Formation at High Redshift
Pettini, Max; Ellison, Sara L.; Shapley, Alice E. +1 more
We present the results of a series of imaging and spectroscopic observations aimed at identifying and studying the galaxy responsible for the zabs=3.38639 damped Lyα system in the zem=3.61 quasar Q0201+1120. We find that the damped Lyα systems (DLA) is part of a concentration of matter that includes at least four galaxies (pr…