Variability of the proton-to-electron mass ratio on cosmological scales (2008)
Wendt, Martin, Reimers, Dieter
So far the only seemingly significant indication of a cosmological variation exists for the proton-to-electron mass ratio as stated by Reinhold et al. (2006). The measured indication of variation is...
New extremely metal-poor stars in the Galactic halo (2008)
Cohen, Judith G., Christlieb, Norbert, McWilliam, Andrew, Shectman, Stephen, Thompson, Ian, Melendez, Jorge, ...
We present a detailed abundance analysis based on high-resolution and high signal-to-noise spectra of eight extremely metal-poor (EMP) stars with [ Fe/H ] ≾ − 3.5 dex, four of which are new. Only...
Bounds on the fine structure constant variability from FeII absorption lines in QSO spectra (2007)
Molaro, Paolo, Reimers, Dieter, Agafonova, Irina I., Levshakov, Sergei A.
The Single Ion Differential alpha Measurement (SIDAM) method for measuring fine stucture variations (daa)and its figures of merit are illustrated together with the results produced by means of FeII...
A new type of extremely metal-poor star (2007)
Cohen, Judith G., McWilliam, Andrew, Christlieb, Norbert, Shectman, Stephen, Thompson, Ian, Melendez, Jorge, ...
We present an abundance analysis for the extremely metal-poor (EMP) star HE 1424-0241 based on high-dispersion spectra from HIRES at Keck. This star is a giant on the lower red giant branch with...
A New Type of Extremely Metal Poor Star (2007)
Cohen, Judith G., McWilliam, Andrew, Christlieb, Norbert, Shectman, Stephen, Thompson, Ian, Melendez, Jorge, ...
We present an abundance analysis for the extremely metal poor star HE1424-0241 based on high dispersion spectra from HIRES at Keck. This star is a giant on the lower red giant branch with [Fe/H] ~...
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
We present a sample of 1777 bright (9 < B < 14) metal-poor candidates selected from the Hamburg/ESO Survey (HES). Despite saturation effects present in the red portion of the HES objective-prism...
High-Precision Measurements of Delta alpha/alpha from QSO Absorption Spectra (2006)
Levshakov, Sergei A., Molaro, Paolo, Lopez, Sebastian, D'Odorico, Sandro, Centurion, Miriam, Bonifacio, Piercarlo, ...
Precise radial velocity measurements (delta v/c ~ 10^{-7}) of FeII lines in damped Ly-alpha systems from very high quality VLT/UVES spectra of quasars HE0515-4414 and Q1101-264 are used to probe...
Chand, Hum, Srianand, Raghunathan, Petitjean, Patrick, Aracil, Bastien, Quast, Ralf, Reimers, Dieter
We present a detailed analysis of a very high resolution (R\approx 112,000) spectrum of the quasar HE 0515-4414 obtained using the High Accuracy Radial velocity Planet Searcher (HARPS) mounted on the...
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
Abstract not available.
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
Abstract not available.
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
Abstract not available.
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
Abstract not available.
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
Abstract not available.
HE 0437-5439 -- an unbound hyper-velocity main-sequence B-type star (2005)
Edelmann, Heinz, Napiwotzki, Ralf, Heber, Uli, Christlieb, Norbert, Reimers, Dieter
We report the discovery of a 16th magnitude star, HE0437-5439, with a heliocentric radial velocity of +723+-3km/s. A quantitative spectral analysis of high-resolution optical spectra obtained with...
HE 0047-1756: A new gravitationally lensed double QSO (2004)
Wisotzki, Lutz, Schechter, Paul L., Chen, Hsiao-Wen, Richstone, Douglas, Jahnke, Knud, Sanchez, Sebastian F., ...
The quasar HE 0047-1756, at z=1.67, is found to be split into two images 1.44" apart by an intervening galaxy acting as a gravitational lens. The flux ratio for the two components is roughly 3.5:1,...
The associated system of HE2347-4342 (2004)
Fechner, Cora, Baade, Robert, Reimers, Dieter
We present an analysis of the complex associated system of the high-redshift QSO HE2347-4342. Absorption features of HI, CIII, CIV, NV, and OVI with up to 16 components occur in the optical spectral...
Probing the variability of the fine-structure constant with the VLT/UVES (2003)
Quast, Ralf, Reimers, Dieter, Levshakov, Sergei A.
We assess the cosmological variability of the fine-structure constant from the analysis of an ensemble of Fe II absorption lines at the redshift z=1.15 toward the QSO HE 0515-4414 by means of the...
HE0241-0155 - Evidence for a large scale homogeneous field in a highly magnetic white dwarf (2003)
Reimers, Dieter, Jordan, Stefan, Christlieb, Norbert
In the course of the Hamburg/ESO survey we have discovered a white dwarf whose spectrum exhibits many similarities with the prototype of magnetic white dwarfs Grw+70$^{\circ}$8247. In particular...
Shull, J. Michael, Tumlinson, Jason, Giroux, Mark L., Kriss, Gerard A., Reimers, Dieter
We provide an in-depth analysis of the He II and H I absorption in the intergalactic medium (IGM) at redshifts z = 2.3-2.9 toward HE 2347-4342, using spectra from the Far Ultraviolet Spectroscopic...
Janknecht, Eckart, Baade, Robert, Reimers, Dieter
Spectroscopy with HST/STIS Echelle and VLT/UVES of the bright QSO HE 0515-4414 (z_em =1.73, B = 15.0) offers for the first time the opportunity to study the Lyman alpha forest in the redshift range...
HE 0435-1223: a wide separation quadruple QSO and gravitational lens (2002)
Wisotzki, Lutz, Schechter, Paul L., Bradt, Hale V., Heinmueller, Janine, Reimers, Dieter
We report the discovery of a new gravitationally lensed QSO, at a redshift z = 1.689, with four QSO components in a cross-shaped arrangement around a bright galaxy. The maximum separation between...
Fine-structure diagnostics of neutral carbon toward HE 0515-4414 (2002)
Quast, Ralf, Baade, Robert, Reimers, Dieter
New high-resolution high signal-to-noise spectra of the $z=1.15$ damped Lyman $\alpha$ (DLA) system toward the quasi-stellar object HE 0515-4414 reveal absorption lines of the multiplets 2 and 3 in...
Lopez, Sebastian, Reimers, Dieter, D'Odorico, Sandro, Prochaska, Jason X.
We have obtained a high resolution, high S/N UVES spectrum of the bright QSO HE2243-6031 to analyze the damped Ly-alpha system (DLA) observed at z=2.33. The metallicity of this system is 1/12 solar...
Reimers, Dieter, Baade, Robert, Hagen, Hans-Juergen, Lopez, Sebastian
STIS Echelle observations at a resolution of 10 km/s and UVES/VLT spectroscopy at a resolution of 7 km/s of the luminous QSO HE 0515-4414 (z_em = 1.73, B = 15.0) reveal four intervening O VI...
HST spectroscopy of the double QSO HS 1216+5032 AB (2000)
Lopez, Sebastian, Hagen, Hans-Juergen, Reimers, Dieter
(Abridged) We report on HST FOS observations of the double QSO HS 1216+5032 AB (z(A)=1.455; z(B)=1.451, and angular separation theta=9 arcsec). An unusual broad-absorption-line (BAL) system is...
An Automated Search for Metal-Poor Halo Stars in the Hamburg/ESO Objective-Prism Survey (1998)
Christlieb, Norbert, Wisotzki, Lutz, Reimers, Dieter, Gehren, Thomas, Reetz, Johannes, Beers, Timothy C.
An automated search for metal-poor stars is carried out in the course of the Hamburg/ESO objective-prism survey (HES), which covers the full southern sky at Galactic latitudes |b| \gtrsim 30 degrees....
Lopez, Sebastian, Reimers, Dieter, Rauch, Michael, Sargent, Wallace L. W., Smette, Alain
Using new HST/FOS, NTT/EMMI, and Keck/HIRES spectra of the gravitationally-lensed double QSO HE 1104-1805 AB (z=2.31, \theta=3.2), and assuming UV photoionization by a metagalactic radiation field,...