Search Publications
The Low End of the Initial Mass Function in Young Large Magellanic Cloud Clusters. I. The Case of R136
Leitherer, Claus; Clampin, Mark; Nota, Antonella +2 more
We report the result of a study in which we have used very deep broadband V and I Wide Field Planetary Camera 2 images of the R136 cluster in the Large Magellanic Cloud from the Hubble Space Telescope archive to sample the luminosity function below the detection limit of 2.8 Msolar previously reached. In these new deeper images, we dete…
O VI and Multicomponent H I Absorption Associated with a Galaxy Group in the Direction of PG 0953+415: Physical Conditions and Baryonic Content
Tripp, Todd M.; Savage, Blair D.
We report the discovery of an O VI absorption system at zabs=0.14232 in a high-resolution FUV spectrum of PG 0953+415 obtained with the Space Telescope Imaging Spectrograph (STIS). Both lines of the O VI λλ1032, 1038 doublet and multicomponent H I Lyα absorption are detected, but the N V doublet and the strong lines of C II and Si III a…
Far-infrared Detection of C3 in Sagittarius B2 and IRC +10216
Cernicharo, José; Goicoechea, Javier R.; Caux, Emmanuel
We report on the detection of nine lines of the ν2 bending mode of triatomic carbon, C3, in the direction of Sagittarius B2. The R(4) and R(2) lines of C3 have been also detected in the carbon-rich star IRC +10216. The abundances of C3 in the direction of Sgr B2 and IRC +10216 are ~=3×10-8 and…
A Jet Model for the Afterglow Emission from GRB 000301C
Menten, K. M.; Galama, T. J.; Berger, E. +11 more
We present broadband radio observations of the afterglow of GRB 000301C, spanning from 1.4 to 350 GHz for the period of 3-130 days after the burst. These radio data, in addition to measurements in the optical bands, suggest that the afterglow arises from a collimated outflow, i.e., a jet. To test this hypothesis in a self-consistent manner, we emp…
Low- and High-Ionization Absorption Properties of Mg II Absorption-selected Galaxies at Intermediate Redshifts. II. Taxonomy, Kinematics, and Galaxies
Charlton, Jane C.; Schneider, Donald P.; Steidel, Charles C. +4 more
We examine a sample of 45 Mg II absorption-selected systems over the redshift range 0.4-1.4 in order to better understand the range of physical conditions present in the interstellar and halo gas associated with intermediate redshift galaxies. Mg II and Fe II absorption profiles were observed at a resolution of ~=6 km s-1 with HIRES/Kec…
Dissipation of Slow Magnetosonic Waves in Coronal Plumes
Nakariakov, V. M.; Ofman, L.; Sehgal, N.
Recently, slow magnetosonic waves were identified in polar plumes, at heights up to about 1.2 Rsolar using the Extreme Ultraviolet Imaging Telescope (EIT) observations of quasi-periodic EUV intensity fluctuations, and higher in the corona using the Ultraviolet Coronagraph Spectrometer (UVCS) white-light channel. First, we derive the lin…
Locally Optimally Emitting Clouds and the Variable Broad Emission Line Spectrum of NGC 5548
Goad, Michael R.; Korista, Kirk T.
In recent work Baldwin et al. proposed that in the geometrically extended broad-line regions (BLRs) of quasars and active galactic nuclei, a range in line-emitting gas properties (e.g., density, column density) might exist at each radius and showed that under these conditions the broad emission line spectra of these objects may be dominated by sel…
The Narrow-Line Regions of LINERS as Resolved with the Hubble Space Telescope
Ho, Luis C.; Maoz, Dan; Eracleous, Michael +1 more
Low-ionization nuclear emission-line regions (LINERs) exist in the nuclei of a large fraction of luminous galaxies, but their connection with the active galactic nucleus (AGN) phenomenon has remained elusive. We present Hubble Space Telescope (HST) narrowband ([O III] λ5007 and Hα+[N II]) emission-line images of the central regions of 14 galaxies …
Turbulent Solar Convection and Its Coupling with Rotation: The Effect of Prandtl Number and Thermal Boundary Conditions on the Resulting Differential Rotation
Toomre, J.; Elliott, J. R.; Miesch, M. S.
The dynamics of the vigorous convection in the outer envelope of the Sun must determine the transport of energy, angular momentum, and magnetic fields and must therefore be responsible for the observed surface activity and the angular velocity profile inferred helioseismically from SOI-MDI p-mode frequency splittings. Many different theoretical tr…
The Contribution of Field OB Stars to the Ionization of the Diffuse Ionized Gas in M33
Hoopes, Charles G.; Walterbos, René A. M.
We present a study of the ionizing stars associated with the diffuse ionized gas (DIG) and H II regions in the nearby spiral galaxy M33. We compare our Schmidt Hα image to the far-ultraviolet (FUV, 1520 Å) image from the Ultraviolet Imaging Telescope (UIT). The Hα/FUV ratio is higher in H II regions than in the DIG, suggesting an older population …