Search Publications
The Stellar Populations and Evolution of Lyman Break Galaxies
Papovich, Casey; Dickinson, Mark; Ferguson, Henry C.
Using deep near-infrared and optical observations of the Hubble Deep Field-North from the Hubble Space Telescope NICMOS and WFPC2 instruments and from the ground, we examine the spectral energy distributions (SEDs) of Lyman break galaxies (LBGs) at 2.0<~z<~3.5 in order to investigate their stellar population properties. The ultraviolet-optic…
Hubble Space Telescope Time-Series Photometry of the Transiting Planet of HD 209458
Burrows, Adam; Gilliland, Ronald L.; Charbonneau, David +2 more
We have observed four transits of the planet of HD 209458 using the STIS spectrograph on the Hubble Space Telescope (HST). Summing the recorded counts over wavelength between 582 and 638 nm yields a photometric time series with 80 s time sampling and relative precision of about 1.1×10-4 per sample. The folded light curve can be fitted w…
Infrared Space Observatory's Discovery of C4H2, C6H2, and Benzene in CRL 618
Waters, L. B. F. M.; Cernicharo, José; Tielens, A. G. G. M. +4 more
We report on the detection with the Infrared Space Observatory (ISO), for the first time in the circumstellar medium, of the polyacetylenic chains C4H2 and C6H2 and of benzene (C6H6) in the direction of the proto-planetary nebula CRL 618. Surprisingly, the abundances of di- and tria…
Observational Constraints on the Formation and Evolution of Binary Stars
Ghez, A. M.; White, R. J.
We present a high spatial resolution multiwavelength survey of 44 young binary star systems in Taurus-Auriga with separations of 10-1000 AU. These observations, which were obtained using the Hubble Space Telescope and the NASA Infrared Telescope Facility, quadruple the number of close (less than 100 AU) binary stars with spatially resolved measure…
The Infrared Spectral Energy Distribution of Normal Star-forming Galaxies
Dale, Daniel A.; Helou, George; Silbermann, Nancy A. +2 more
We present a new phenomenological model for the spectral energy distribution of normal star-forming galaxies between 3 and 1100 µm. A sequence of realistic galaxy spectra are constructed from a family of dust emission curves assuming a power-law distribution of dust mass over a wide range of interstellar radiation fields. For each interstell…
The Galactic Disk Mass Budget. I. Stellar Mass Function and Density
Chabrier, Gilles
In this paper, we use the general theory worked out within the past few years for the structure and the evolution of low-mass stars to derive the stellar mass function in the Galactic disk down to the vicinity of the hydrogen-burning limit from the observed nearby luminosity functions. The accuracy of the mass-magnitude relationships derived from …
The Metamorphosis of SN 1998bw
Leibundgut, Bruno; Kouveliotou, Chryssa; Nomoto, Ken'ichi +23 more
We present and discuss the photometric and spectroscopic evolution of the peculiar SN 1998bw, associated with GRB 980425, through an analysis of optical and near-IR data collected at ESO-La Silla. The spectroscopic data, spanning the period from day -9 to day +376 (relative to B maximum), have shown that this supernova (SN) was unprecedented, alth…
Far-Infrared Spectroscopy of Normal Galaxies: Physical Conditions in the Interstellar Medium
Helou, G.; Contursi, A.; Stacey, G. +10 more
The most important cooling lines of the neutral interstellar medium (ISM) lie in the far-infrared (FIR). We present measurements by the Infrared Space Observatory Long Wavelength Spectrometer of seven lines from neutral and ionized ISM of 60 normal, star-forming galaxies. The galaxy sample spans a range in properties such as morphology, FIR colors…
Quasi-Stellar Objects, Ultraluminous Infrared Galaxies, and Mergers
Stockton, Alan; Canalizo, Gabriela
We test the hypothesis that QSOs are formed via strong tidal interactions or mergers, initially going through an ultraluminous infrared phase. Our approach is to look for traces of this phase in the host galaxies of QSOs. We select a sample of low-redshift bona fide QSOs that may be in a transitionary stage between ultraluminous infrared galaxies …
On the Nature of the Central Source in η Carinae
Davidson, K.; Hillier, D. John; Gull, T. +1 more
Long-slit spectroscopic observations of η Carinae and its Homunculus have recently been obtained using STIS on the Hubble Space Telescope (HST). We have extracted the spectrum of the central source using a 0.1"×0.13" aperture. As expected, the spectrum is very different from ground-based spectra obtained under normal seeing conditions (i.e., 1")-t…