Science Archives Publication System

A Near-Infrared Stellar Census of Blue Compact Dwarf Galaxies: The Wolf-Rayet Galaxy I Zw 36

DOI: 10.1086/321071 Bibcode: 2001AJ....121.3007S

Greggio, Laura; Hopp, Ulrich; Schulte-Ladbeck, Regina E. +2 more

We report the results of near-IR imaging in J and H, of I Zw 36 (~Z_solar/14) with the Hubble Space Telescope. Whereas imaging with the pre-COSTAR Faint Object Camera (FOC) previously resolved hot and massive stars in the near-UV, the NICMOS data furnish a census of the cool, intermediate- and low-mass stars. There clearly was star forma…

2001 • The Astronomical Journal

eHST 57

The Interaction between the Interstellar Medium and Star Formation in the Dwarf Starburst Galaxy NGC 4214

DOI: 10.1086/318775 Bibcode: 2001AJ....121..727W

Scoville, Nick; Walter, Fabian; Taylor, Christopher L. +2 more

We present the first interferometric study of the molecular gas in the metal-poor dwarf starburst galaxy NGC 4214. Our map of the ¹²CO (1-0) emission, obtained at the Owens Valley Radio Observatory's millimeter array, reveals an unexpected structural wealth. We detected three regions of molecular emission in the northwest, southeast, an…

2001 • The Astronomical Journal

eHST 57

Morphology and Evolution of the Large Magellanic Cloud Planetary Nebulae

DOI: 10.1086/319013 Bibcode: 2001ApJ...548..727S

Mutchler, Max; Blades, J. Chris; Balick, Bruce +2 more

The LMC is ideal for studying the coevolution of planetary nebulae (PNs) and their central stars in that the debilitating uncertainties of the Galactic PN distance scale and selection biases from attenuation by interstellar dust do not apply. We present images and analyze slitless spectra that were obtained in a survey of Large Magellanic Cloud PN…

2001 • The Astrophysical Journal

eHST 57

The Jet and the Supernova in GRB 990712

DOI: 10.1086/320328 Bibcode: 2001ApJ...552L.121B

Christensen, L.; Hjorth, J.; Jakobsson, P. +2 more

The optical light curve of the afterglow following the gamma-ray burst GRB 990712 is reexamined. Recently published polarization measurements of that source require a collimated outflow geometry that in turn predicts a break in the light curve. We show that the V-band light curve is consistent with such a break and that the postbreak light-curve e…

2001 • The Astrophysical Journal

eHST 57

Generation mechanism for magnetic holes in the solar wind

DOI: 10.1029/2000GL012592 Bibcode: 2001GeoRL..28.1355B

Tsurutani, B. T.; Goldstein, B. E.; Neugebauer, M. +1 more

A new mechanism for generation of magnetic holes in the solar wind is presented. In the high speed solar wind, large-amplitude right-hand polarized Alfvénic wave packets propagating at large angles to the ambient magnetic field are shown to generate magnetic holes (MHs). Characteristics of these holes crucially depend on plasma β (β being the rati…

2001 • Geophysical Research Letters

Ulysses 57

The Rich Ultraviolet Spectrum of Vibrationally Excited Interstellar H₂ toward HD 37903

DOI: 10.1086/320504 Bibcode: 2001ApJ...553L..59M

Sofia, Ulysses J.; Meyer, David M.; Draine, B. T. +2 more

Based on recent high-resolution Hubble Space Telescope Space Telescope Imaging Spectrograph observations over the 1160-1360 Å wavelength region, we have discovered that HD 37903 (the illuminating star of the bright reflection nebula NGC 2023 in Orion) exhibits a rich spectrum of vibrationally excited interstellar H₂ absorption. We have …

2001 • The Astrophysical Journal

eHST 57

Far-infrared mapping of the starburst galaxy NGC 253 with ISOPHOT

DOI: 10.1051/0004-6361:20011102 Bibcode: 2001A&A...377...73R

Lemke, D.; Radovich, M.; Kahanpää, J.

A 180 mu m map and strip maps at 120 and 180 mu m were obtained for the edge-on starburst galaxy NGC 253 with ISOPHOT, the photometer on board the Infrared Space Observatory. We compare these observations with those obtained by IRAS at 60 mu m and 100 mu m and derive the far-infrared spectral energy distribution at different loc…

2001 • Astronomy and Astrophysics

ISO 56

Kinematics from spectroscopy with a wide slit: detecting black holes in galaxy centres

DOI: 10.1046/j.1365-8711.2001.04307.x Bibcode: 2001MNRAS.323..831M

Binney, James; Maciejewski, Witold

We consider long-slit emission-line spectra of galactic nuclei when the slit is wider than the instrumental point spread function, and the target has large velocity gradients. The finite width of the slit generates complex distributions of brightness at a given spatial point in the measured spectrum, which can be misinterpreted as coming from addi…

2001 • Monthly Notices of the Royal Astronomical Society

eHST 56

Modulation of Jovian and galactic electrons in the heliosphere: 2. Radial transport of a few MeV electrons

DOI: 10.1029/2001JA000170 Bibcode: 2001JGR...10629313F

Fichtner, H.; Ferreira, S. E. S.; Potgieter, M. S. +3 more

Previously, the latitudinal transport of ~7 MeV electrons was studied by comparing the results of a newly developed three-dimensional model, based on the numerical solution of Parker's transport equation including the Jovian source, with Ulysses observations. Here, the radial transport of ~16 MeV electrons is studied by comparing the model results…

2001 • Journal of Geophysical Research

Ulysses 56

Interstellar Bubbles in Two Young H II Regions

DOI: 10.1086/322067 Bibcode: 2001AJ....122..921N

Danforth, Charles W.; Nazé, Yaël; Chu, You-Hua +3 more

Massive stars are expected to produce wind-blown bubbles in the interstellar medium; however, ring nebulae, suggesting the existence of bubbles, are rarely seen around main-sequence O stars. To search for wind-blown bubbles around main-sequence O stars, we have obtained high-resolution Hubble Space Telescope WFPC2 images and high-dispersion echell…

2001 • The Astronomical Journal

eHST 56