Search Publications
Hubble Space Telescope WFPC2 Morphologies of K-selected Extremely Red Galaxies
Yan, Lin; Thompson, David
We selected 115 extremely red objects (EROs) from deep Hubble Space Telescope (HST) WFPC2 archive data combined with ground-based K-band images, with (F814W-Ks) >= 4, K-band signal-to-noise ratio >=5, and a median limiting Ks magnitude of ~18.7, over a corresponding area of 228 arcmin2, for a morphological st…
A wavelet packets equalization technique to reveal the multiple spatial-scale nature of coronal structures
Stenborg, G.; Cobelli, P. J.
Precise determination of onset times of dynamical events as observed by coronagraphs requires a high-degree-of-accuracy tracking of the structures involved. In particular, early steps in the evolution turn to be of utmost importance. However, corresponding features often lack the sharpness needed to obtain unambiguous results. To overcome this con…
A radio continuum and infrared study of Galactic H II regions
Tielens, A. G. G. M.; van der Hulst, J. M.; Martín-Hernández, N. L.
We present observations of the 4.8 and 8.6 GHz continuum emission towards 11 southern H Ii regions made with the Australian Telescope Compact Array. The observed objects were selected from the Infrared Space Observatory (ISO) spectral catalogue of compact H Ii regions \citep{peeters:catalogue}. The morphologies observed for practically all the sou…
Chemical Abundances in Broad Emission Line Regions: The ``Nitrogen-loud'' Quasi-Stellar Object Q0353-383
Dietrich, M.; Korista, K. T.; Ferland, G. J. +3 more
The intensity of the strong N V λ1240 line relative to C IV λ1549 or to He II λ1640 has been proposed as an indicator of the metallicity of quasi-stellar object (QSO) broad emission line regions, allowing abundance measurements in a large number of QSOs out to the highest redshifts. Previously, it had been shown that the (normally) much weaker lin…
Physical Parameters of the 2000 February 11 Coronal Mass Ejection: Ultraviolet Spectra versus White-Light Images
Raymond, J. C.; Chen, J.; Ciaravella, A. +5 more
We present spectra of a three-part coronal mass ejection (CME) observed by the Ultraviolet Coronagraph Spectrometer aboard SOHO on 2000 February 11. Images of the CME in different spectral lines show how the morphology depends on the temperature, density, and outflow speed of the ejected plasma. The H I Lyα is the line that best resembles the whit…
Advanced Camera for Surveys Observations of Young Star Clusters in the Interacting Galaxy UGC 10214
Ford, H. C.; Infante, L.; Feldman, P. D. +31 more
We present the first Advanced Camera for Surveys (ACS) observations of young star clusters in the colliding/merging galaxy UGC 10214. The observations were made as part of the Early Release Observation (ERO) program for the newly installed ACS during service mission SM3B for the Hubble Space Telescope (HST). Many young star clusters can be identif…
Highly Ionized Gas in the Galactic Halo: A FUSE Survey of O VI Absorption toward 22 Halo Stars
Savage, B. D.; Sembach, K. R.; Howk, J. C. +1 more
Far Ultraviolet Spectroscopic Explorer (FUSE) spectra of 22 Galactic halo stars are studied to determine the amount of O VI in the Galactic halo between ~0.3 and ~10 kpc from the Galactic midplane. Strong O VI λ1031.93 absorption was detected toward 21 stars, and a reliable 3 σ upper limit was obtained toward HD 97991. The weaker member of the O V…
The INTEGRAL spacecraft - in-orbit performance
Winkler, C.; Clausen, K.; Much, R. +4 more
The INTEGRAL satellite was successfully launched from Baikonur on 17 October, 2002. INTEGRAL is an observatory for gamma-ray astronomy. The goals are to provide unprecedented high resolution imaging capability for unambiguous identification of gamma ray sources and high energy resolution for line spectroscopy. This paper summarises the actual orbi…
Kink and Longitudinal Oscillations in the Magnetic Network on the Sun: Nonlinear Effects and Mode Transformation
van Ballegooijen, A. A.; Hasan, S. S.; Kalkofen, W. +1 more
We examine the propagation of kink and longitudinal waves in the solar magnetic network. Previously, we investigated the excitation of network oscillations in vertical magnetic flux tubes through buffeting by granules and found that footpoint motions of the tubes can generate sufficient wave energy for chromospheric heating. We assumed that the ki…
The physical structure of high-mass star-forming cores
van der Tak, F. F. S.; Hatchell, J.
We present models of the temperature and density structure of the envelopes of ten deeply embedded massive stars associated with ultracompact HII regions. Constraints come from 60-1300 mum photometry including ISO-LWS spectra, maps at 450 and 850 mum , and CS emission line data. Radial profiles extracted from the maps after removing neighbouring s…