Search Publications
Quantitative Morphology of Galaxies in the Hubble Deep Field
Simard, Luc; Marleau, Francine R.
We measure quantitative structural parameters of galaxies in the Hubble deep field (HDF) on the drizzled F814W images. Our structural parameters are based on a two-component surface brightness made up of a Sérsic profile and an exponential profile. We compare our results to the visual classification of van den Bergh et al. and the C-A classificati…
Resolved 200mu M images of nearby galaxies - evidence for an extended distribution of cold dust
Bianchi, S.; Gear, W.; Davies, J. I. +6 more
We present resolved 200mu m images for 8 nearby galaxies observed with the Infrared Space Observatory (ISO). By comparing the 200mu m observations with IRAS 60mu m and 100mu m data, we find that cold dust becomes more dominant at larger radii. We infer a grain temperature of 18-21 K for this cold component i.e. about 10 K lower than the warm dust …
How many low-mass stars do destroy (3) He?
Charbonnel, C.; Do Nascimento, J. D., Jr.
We recall the current status of the long-standing (3) He problem, and its possible connection with chemical anomalies on the red giant branch. In this context, we collect in the literature all the available observations of the carbon isotopic ratio in field and cluster giant stars. Using the HIPPARCOS parallaxes, we get constraints on the evolutio…
Broad P V Absorption in the QSO PG 1254+047: Column Densities, Ionizations, and Metal Abundances in Broad Absorption Line Winds
Hamann, Fred
This paper discusses the detection of P V λλ1118, 1128 and other broad absorption lines (BALs) in archival Hubble Space Telescope spectra of the low-redshift BAL QSO PG 1254+047. The P V identification is secured by excellent redshift and profile coincidences with the other BALs, such as C IV λλ1548, 1550 and Si IV λλ1393, 1403, and by photoioniza…
Heliospheric tomography using interplanetary scintillation observations 2. Latitude and heliocentric distance dependence of solar wind structure at 0.1-1 AU
Jackson, B. V.; Tokumaru, M.; Kojima, M. +4 more
Interplanetary scintillation is a useful means to measure the solar wind in regions inaccessible to in situ observation. However, interplanetary scintillation measurements involve a line-of-sight integration, which relates contributions from all locations along the line of sight to the actual observation. We have developed a computer assisted tomo…
Exploring Cluster Elliptical Galaxies as Cosmological Standard Rods
Saglia, R. P.; Bender, Ralf; Greggio, Laura +4 more
We explore the possibility of calibrating massive cluster elliptical galaxies as cosmological standard rods using the fundamental plane relation combined with a correction for luminosity evolution. Although cluster ellipticals certainly formed in a complex way, their passive evolution out to redshifts of about 1 indicates that basically all major …
Multimodal Distributions along the Horizontal Branch
Ferraro, Francesco R.; Paltrinieri, Barbara; Fusi Pecci, Flavio +2 more
We report on the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) U, V, and far-ultraviolet observations of three galactic globular clusters (GGCs), NGC 5272 = M3, NGC 6205 = M13, and NGC 6093 = M80. Two of these clusters (namely, M13 and M80) have horizontal-branch (HB) tails that extend to the helium-burning main sequence, with…
A Z = 5.34 Galaxy Pair in the Hubble Deep Field
Dey, Arjun; Bunker, Andrew; Spinrad, Hyron +5 more
We present spectrograms of the faint V-drop (V_606 = 28.1, I_814 = 25.6) galaxy pair HDF 3-951.1 and HDF 3-951.2 obtained at the Keck II Telescope. In a recent study, Fernández-Soto, Lanzetta, & Yahil derive a photometric redshift of z_ph=5.28^+0.34_-0.41 (2 sigma) for these galaxies; our integrated spectrograms show a large and abrupt discont…
Hubble Space Telescope Wide Field Planetary Camera 2 Observations of eta Carinae
Frank, Adam; Davidson, Kris; Bally, John +3 more
Hubble Space Telescope (HST) continuum and emission-line images of eta Carinae obtained with the Planetary Camera (PC) of the Wide Field Planetary Camera 2 show a startling wealth of detailed structure in the expanding Homunculus Nebula and outer debris field. Using a combination of dithering and image deconvolutions, we have achieved a resolution…
The AC 2000: The Astrographic Catalogue on the System Defined by the HIPPARCOS Catalogue
Urban, S. E.; Wycoff, G. L.; Martin, J. C. +4 more
The AC 2000 is a positional catalog of 4,621,836 stars covering the entire sky. The average epoch of position is 1907. The data are from the images measured and published as part of the Astrographic Catalogue (AC). The positions are on the system defined by the Hipparcos Catalogue, having originally been reduced plate-by-plate using the Astrograph…