Search Publications
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…
A Correlation between Galaxy Light Concentration and Supermassive Black Hole Mass
Graham, Alister W.; Trujillo, I.; Erwin, Peter +1 more
We present evidence for a strong correlation between the concentration of bulges and the mass of their central supermassive black hole (Mbh)-more concentrated bulges have more massive black holes. Using Cre(1/3) from Trujillo, Graham, & Caon as a measure of bulge concentration, we find that log(Mbh/M…
Radio Signatures of Coronal Mass Ejection Interaction: Coronal Mass Ejection Cannibalism?
Kaiser, M. L.; Howard, R. A.; Gopalswamy, N. +2 more
We report the first detection at long radio wavelengths of interaction between coronal mass ejections (CMEs) in the interplanetary medium. The radio signature is in the form of intense continuum-like radio emission following an interplanetary type II burst. At the time of the radio enhancement, coronagraphic images show a fast CME overtaking a slo…
Clear Evidence of Reconnection Inflow of a Solar Flare
Yokoyama, T.; Akita, K.; Morimoto, T. +2 more
We found an important piece of evidence for magnetic reconnection inflow in a flare on 1999 March 18. The flare occurred on the northeast limb, displaying a nice cusp-shaped soft X-ray loop and a plasmoid ejection typical for the long-duration events. The EUV observation of the same flare shows us a bubble-like void ejection. The core of this EUV …
A Possible Cepheid-like Luminosity Estimator for the Long Gamma-Ray Bursts
Ramirez-Ruiz, Enrico; Hurley, Kevin; Reichart, Daniel E. +3 more
We present a possible Cepheid-like luminosity estimator for the long gamma-ray bursts based on the variability of their light curves. To construct the luminosity estimator, we use CGRO/BATSE data for 13 bursts, Wind/Konus data for five bursts, Ulysses/GRB data for one burst, and NEAR/XGRS data for one burst. Spectroscopic redshifts, peak fluxes, a…
Observational Determination of the Rate of Magnetic Helicity Transport through the Solar Surface via the Horizontal Motion of Field Line Footpoints
Chae, Jongchul
Magnetic helicity may be transported to the solar corona through the solar surface either via the passage of helical magnetic field lines from below or via the shuffling of footpoints of preexisting coronal field lines. In this Letter, we show how to observationally determine the rate of magnetic helicity transport via photospheric footpoint shuff…