Search Publications
Discovery of the Low-Redshift Optical Afterglow of GRB 011121 and Its Progenitor Supernova SN 2001ke
Infante, L.; Kirshner, R. P.; Garnavich, P. M. +10 more
We present the discovery and follow-up observations of the afterglow of the gamma-ray burst GRB 011121 and its associated supernova SN 2001ke. Images were obtained with the Optical Gravitational Lensing Experiment 1.3 m telescope in BVRI passbands, starting 10.3 hr after the burst. The temporal analysis of our early data indicates a steep decay, i…
Circumnuclear Dust in Nearby Active and Inactive Galaxies. II. Bars, Nuclear Spirals, and the Fueling of Active Galactic Nuclei
Pogge, Richard W.; Mulchaey, John S.; Martini, Paul +1 more
We present a detailed study of the relation between circumnuclear dust morphology, host-galaxy properties, and nuclear activity in nearby galaxies. We use our sample of 123 nearby galaxies with visible-near-infrared color maps from the Hubble Space Telescope to create well-matched, ``paired'' samples of 28 active and 28 inactive galaxies, as well …
A Dynamical Model for the Globular Cluster G1
Baumgardt, Holger; Makino, Junichiro; Hut, Piet +2 more
We present a comparison between the observational data on the kinematical structure of G1 in M31, obtained with the Hubble Space Telescope Wide Field Planetary Camera 2 and Space Telescope Imaging Spectrograph instruments, and the results of dynamical simulations carried out using the special purpose computer GRAPE-6. We have obtained good fits fo…
X-Ray Emission from the Hot Interstellar Medium and Southwest Radio Lobe of the Nearby Radio Galaxy Centaurus A
Churazov, E.; Hardcastle, M. J.; Worrall, D. M. +5 more
We present results from two Chandra/ACIS-I observations and one XMM-Newton observation of X-ray emission from the interstellar medium (ISM) and the inner radio lobes of the nearby radio galaxy Centaurus A. The ISM has an average radial surface brightness profile that is well described by a β-model profile with index β=0.40+/-0.04 and a temperature…
On the Central Structure of M15
Baumgardt, Holger; Makino, Junichiro; Hut, Piet +2 more
We present a detailed comparison between the latest observational data on the kinematical structure of the core of M15, obtained with the Hubble Space Telescope Space Telescope Imaging Spectrograph and Wide Field Planetary Camera 2 instruments, and the results of dynamical simulations carried out using the special purpose GRAPE-6 computer. The obs…
Changes in Solar Dynamics from 1995 to 2002
Basu, Sarbani; Antia, H. M.
Data obtained by the GONG and MDI instruments over the last 7 years are used to study how solar dynamics-both rotation and other large scale flows-has changed with time. In addition to the well-known phenomenon of bands of faster and slower rotation moving toward the equator and pole, we find that the zonal flow pattern rises upward with time. Lik…
Infrared Emission of Normal Galaxies from 2.5 to 12 Micron: Infrared Space Observatory Spectra, Near-Infrared Continuum, and Mid-Infrared Emission Features
Beichman, Charles A.; Dale, Daniel A.; Dinerstein, Harriet L. +6 more
We present ISOPHOT spectra of the regions 2.5-4.9 µm and 5.8-11.6 µm for a sample of 45 disk galaxies from the US Infrared Space Observatory Key Project on Normal Galaxies. The galaxies were selected to span the range in global properties of normal, star-forming disk galaxies in the local universe. The spectra can be decomposed into th…
Coronal Mass Ejections and Solar Polarity Reversal
Howard, R. A.; Gopalswamy, N.; Yashiro, S. +1 more
We report on a close relationship between the solar polarity reversal and the cessation of high-latitude coronal mass ejections (CMEs). This result holds good for individual poles of the Sun for cycles 21 and 23, for which CME data are available. The high-latitude CMEs provide a natural explanation for the disappearance of the polar crown filament…
The Fundamental Plane at z=1.27: First Calibration of the Mass Scale of Red Galaxies at Redshifts z>1
van Dokkum, Pieter G.; Stanford, S. A.
We present results on the fundamental plane of early-type galaxies in the cluster RDCS J0848+4453 at z=1.27. Internal velocity dispersions of three K-selected early-type galaxies are determined from deep Keck spectra, using absorption lines in the rest-frame wavelength range 3400-4000 Å. Structural parameters are determined from Hubble Space Teles…
High-Resolution Measurements of the Dark Matter Halo of NGC 2976: Evidence for a Shallow Density Profile
Bolatto, Alberto D.; Simon, Joshua D.; Blitz, Leo +1 more
We have obtained two-dimensional velocity fields of the dwarf spiral galaxy NGC 2976 in Hα and CO. The high spatial (~75 pc) and spectral (13 and 2 km s-1, respectively) resolution of these observations, along with our multicolor optical and near-infrared imaging, allows us to measure the shape of the density profile of the dark matter …