Search Publications
Rotating Nuclear Rings and Extreme Starbursts in Ultraluminous Galaxies
Downes, D.; Solomon, P. M.
New CO interferometer data show that the molecular gas in infrared ultraluminous galaxies is in rotating nuclear disks or rings. The CO maps yield disk radii, kinematic major axes, rotation speeds, enclosed dynamical masses, and gas masses. The CO brightness temperatures, the double-peaked CO line profiles, the limits on thermal continuum flux fro…
Are Gamma-Ray Bursts in Star-Forming Regions?
Paczyński, Bohdan
The optical afterglow of the gamma-ray burst GRB 970508 (z=0.835) was a few hundred times more luminous than any supernova. Therefore, the name ``hypernova'' is proposed for the whole GRB/afterglow event.
There is tentative evidence that the GRBs 970228, 970508, and 970828 were close to star-forming regions. If this case is strengthened with …Supernova Limits on the Cosmic Equation of State
Filippenko, Alexei V.; Riess, Adam G.; Tonry, John +18 more
We use Type Ia supernovae studied by the High-z Supernova Search Team to constrain the properties of an energy component that may have contributed to accelerating the cosmic expansion. We find that for a flat geometry the equation-of-state parameter for the unknown component, αx = Px/ρx, must be less than -0.55 (95…
Constraints on Cosmological Models from Hubble Space Telescope Observations of High-z Supernovae
Spyromilio, J.; Diercks, A.; Schmidt, B. P. +18 more
We have coordinated Hubble Space Telescope (HST) photometry with ground-based discovery for three supernovae: Type Ia supernovae near z~0.5 (SN 1997ce, SN 1997cj) and a third event at z=0.97 (SN 1997ck). The superb spatial resolution of HST separates each supernova from its host galaxy and leads to good precision in the light curves. We use these …
The Evolution of Early-Type Galaxies in Distant Clusters
Dickinson, Mark; Eisenhardt, Peter R.; Stanford, S. A.
We present results from an optical-infrared photometric study of early-type (E+S0) galaxies in 19 galaxy clusters out to z = 0.9. The galaxy sample is selected on the basis of morphologies determined from Hubble Space Telescope (HST) WFPC2 images and is photometrically defined in the K band in order to minimize redshift-dependent selection biases.…
Star Formation in R136: A Cluster of O3 Stars Revealed by Hubble Space Telescope Spectroscopy
Massey, Philip; Hunter, Deidre A.
The R136 cluster in 30 Doradus is the prototype ``super star cluster,'' and the only example sufficiently close that its massive star content can be studied directly. We have used the Hubble Space Telescope to obtain spectra of 65 of the bluest, most luminous stars in R136 and find that the majority of these stars are of type O3, the hottest, most…
Photoevaporation of Disks and Clumps by Nearby Massive Stars: Application to Disk Destruction in the Orion Nebula
Johnstone, Doug; Bally, John; Hollenbach, David
We present a model for the photoevaporation of circumstellar disks or dense clumps of gas by an external source of ultraviolet radiation. Our model includes the thermal and dynamic effects of 6-13.6 eV far-ultraviolet (FUV) photons and Lyman continuum EUV photons incident upon disks or clumps idealized as spheres of radius rd and enclos…
Distance to M31 with the Hubble Space Telescope and HIPPARCOS Red Clump Stars
Garnavich, P. M.; Stanek, K. Z.
Following the approach by Paczyński & Stanek, we compare the red clump stars with parallaxes known to better than 10% in the Hipparcos catalog with the red clump stars observed in three fields in M31 using the Hubble Space Telescope. There are ~600 and ~6300 such stars in the two data sets, respectively. The local red clump luminosity function…
The Definitive Abundance of Interstellar Oxygen
Meyer, David M.; Jura, M.; Cardelli, Jason A.
Using the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope, we have obtained high signal-to-noise (S/N) ratio echelle observations of the weak interstellar O I λ1356 absorption toward the stars γ Cas, ɛ Per, δ Ori, ɛ Ori, 15 Mon, τ CMa, and γ Ara. In combination with previous GHRS measurements in six other sight lines…
Infrared Observations of Nebular Emission Lines from Galaxies at Z ~= 3
Dickinson, Mark; Giavalisco, Mauro; Pettini, Max +3 more
We present the first results from a program of near-infrared spectroscopy aimed at studying the familiar rest-frame optical emission lines from the H II regions of Lyman break galaxies at z ~= 3. By targeting redshifts that bring the lines of interest into gaps between the strong OH sky emission, we have been successful in detecting Balmer and [O …