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On the Lyalpha emission from gamma-ray burst host galaxies: Evidence for low metallicities
Fruchter, A. S.; Wijers, R. A. M. J.; Pedersen, H. +11 more
We report on the results of a search for Lyalpha emission from the host galaxy of the z=2.140 GRB 011211 and other galaxies in its surrounding field. We detect Lyalpha emission from the host as well as from six other galaxies in the field. The restframe equivalent width of the Lyalpha line from the GRB 011211 host is about 21 Å. This is the fifth …
Spectroscopic Binaries, Velocity Jitter, and Rotation in Field Metal-poor Red Giant and Red Horizontal-Branch Stars
Latham, David W.; Stefanik, Robert P.; Morse, Jon A. +2 more
We summarize 2007 radial velocity measurements of 91 metal-poor field red giants. Excluding binary systems with orbital solutions, our coverage averages 13.7 yr per star, with a maximum of 18.0 yr. We report four significant findings. (1) Sixteen stars are found to be spectroscopic binaries, and we present orbital solutions for 14 of them. The spe…
Changes in Solar Dynamics from 1995 to 2002
Basu, Sarbani; Antia, H. M.
Data obtained by the GONG and MDI instruments over the last 7 years are used to study how solar dynamics-both rotation and other large scale flows-has changed with time. In addition to the well-known phenomenon of bands of faster and slower rotation moving toward the equator and pole, we find that the zonal flow pattern rises upward with time. Lik…
The magnetic field of an isolated neutron star from X-ray cyclotron absorption lines
Caraveo, P. A.; Bignami, G. F.; Mereghetti, S. +1 more
Isolated neutron stars are highly magnetized, fast-rotating objects that form as an end point of stellar evolution. They are directly observable in X-ray emission, because of their high surface temperatures. Features in their X-ray spectra could in principle reveal the presence of atmospheres, or be used to estimate the strength of their magnetic …
Slow-mode standing waves observed by SUMER in hot coronal loops
Solanki, S. K.; Marsch, E.; Curdt, W. +2 more
We report the first detection of postflare loop oscillations seen in both Doppler shift and intensity. The observations were recorded in an Fe Xix line by the SUMER spectrometer on SOHO in the corona about 70 min after an M-class flare on the solar limb. The oscillation has a period of about 17 min in both the Doppler velocity and the intensity, b…
Dynamics of solar coronal loops. I. Condensation in cool loops and its effect on transition region lines
Peter, H.; Hansteen, V. H.; Müller, D. A. N.
We report numerical calculations of the condensation of plasma in short coronal loops, which have several interesting physical consequences. Firstly, we propose a connection between small, cool loops (T < 106 K), which constitute one of the basic components of the solar transition region, and prominences, in the sense that the same p…
The low-level radial velocity variability in Barnard's star (= GJ 699). Secular acceleration, indications for convective redshift, and planet mass limits
Kürster, M.; Hatzes, A. P.; Cochran, W. D. +6 more
We report results from 2 1/2 yr of high precision radial velocity (RV) monitoring of Barnard's star. The high RV measurement precision of the VLT-UT2+UVES of 2.65 m s-1 made the following findings possible. (1) The first detection of the change in the RV of a star caused by its space motion (RV secular acceleration). (2) An anti-correla…
A pulsational approach to near-infrared and visual magnitudes of RR Lyr stars
Degl'Innocenti, S.; Marconi, M.; Bono, G. +3 more
In this paper, we present an improved theoretical scenario concerning near-infrared and visual magnitudes of RR Lyr variables, as based on up-to-date pulsating models. New relations connecting V and K absolute magnitudes with periods, mass, luminosity and metal content are discussed separately for fundamental and first-overtone pulsators. We also …
Infrared Emission of Normal Galaxies from 2.5 to 12 Micron: Infrared Space Observatory Spectra, Near-Infrared Continuum, and Mid-Infrared Emission Features
Beichman, Charles A.; Dale, Daniel A.; Dinerstein, Harriet L. +6 more
We present ISOPHOT spectra of the regions 2.5-4.9 µm and 5.8-11.6 µm for a sample of 45 disk galaxies from the US Infrared Space Observatory Key Project on Normal Galaxies. The galaxies were selected to span the range in global properties of normal, star-forming disk galaxies in the local universe. The spectra can be decomposed into th…
Local galaxy flows within 5 Mpc
Sarajedini, A.; Dolphin, A. E.; Grebel, E. K. +8 more
We present Hubble Space Telescope/WFPC2 images of sixteen dwarf galaxies as part of our snapshot survey of nearby galaxy candidates. We derive their distances from the luminosity of the tip of the red giant branch stars with a typical accuracy of ~ 12%. The resulting distances are 4.26 Mpc (KKH 5), 4.74 Mpc (KK 16), 4.72 Mpc (KK 17), 4.66 Mpc (ESO…