Search for chameleon-like scalar fields with the ammonia method (2009)
Levshakov, S. A., Molaro, P., Lapinov, A. V., Reimers, D., Henkel, C., Sakai, T.
(Abridged) The ammonia method, recently proposed to explore the electron-to-proton mass ratio, mu = m_e/m_p, is applied to nearby dark clouds in the Milky Way. This ratio, being measured in...
Spatial and temporal variations of fundamental constants (2009)
Levshakov, S. A., Agafonova, I. I., Molaro, P., Reimers, D.
Spatial and temporal variations in the electron-to-proton mass ratio, mu, and in the fine-structure constant, alpha, are predicted in non-Standard models aimed to explain the nature of dark energy....
Wendt, M., Reimers, D., Molaro, P.
Cosmology contributes a good deal to the investigation of variation of fundamental physical constants. High resolution data is available and allows for detailed analysis over cosmological distances...
Metal-rich absorbers at high redshifts: abundance patterns (2009)
Levshakov, S. A., Agafonova, I. I., Molaro, P., Reimers, D., Hou, J. L.
(Abbreviated) From six spectra of high-z QSOs, we select eleven metal-rich, Z>=Z_solar, and optically-thin to the ionizing radiation, N(HI)
Koester, D., Voss, B., Napiwotzki, R., Christlieb, N., Homeier, D., Lisker, T., ...
The ESO Supernova Ia Progenitor Survey (SPY) took high-resolution spectra of more than 1000 white dwarfs and pre-white dwarfs. About two thirds of the stars observed are hydrogen-dominated DA white...
Porsev, S. G., Kozlov, M. G., Reimers, D.
In this paper we calculated the relativistic corrections to transition frequencies (q factors) of Fe I for the transitions from the even- and odd-parity states to the ground state. We also carried...
Koester, D., Voss, B., Napiwotzki, R., Christlieb, N., Homeier, D., Lisker, T., ...
Original article can be found at: http://www.aanda.org/ Copyright The European Southern Observatory (ESO) DOI: 10.1051/0004-6361/200912531
Kozlov, M. G., Tupitsyn, I. I., Reimers, D.
We calculate sensitivity coefficients to $\alpha$-variation for the fine-structure transitions (1,0) and (2,1) within $^3P_J[2s^2 2p^2]$ multiplet of the Carbon-like ions C I, N II, O III, Na VI, Mg...
The Antares emission nebula and mass loss of alpha Sco A (2008)
Reimers, D., Baade, R., Braun, K.
The Antares nebula is a peculiar emission nebula seen in numerous Fe II lines and in radio free-free emission, probably associated with the H II region caused by alpha Sco B in the wind of alpha Sco...
Schoerck, T., Christlieb, N., Cohen, J. G., Beers, T. C., Shectman, S., Thompson, I., ...
We determine the metallicity distribution function (MDF) of the Galactic halo by means of a sample of 1638 metal-poor stars selected from the Hamburg/ESO objective-prism survey (HES). The sample was...
The stellar content of the Hamburg/ESO survey. IV. Selection of candidate metal-poor stars (2008)
Christlieb, N., Schoerck, T., Frebel, A., Beers, T. C., Wisotzki, L., Reimers, D.
We present the quantitative methods used for selecting candidate metal-poor stars in the Hamburg/ESO objective-prism survey (HES). The selection is based on the strength of the Ca II K line, B-V...
Levshakov, S. A., Agafonova, I. I., Reimers, D., Hou, J. L., Molaro, P.
(abridged) Aims. To reconstruct the spectral shape of the quasar ionizing radiation in the extreme-UV range (1Ryd 4Ryd which is attributed to the HeII Lyman continuum opacity (tau^HeII_c ~ 1). A...
Kozlov, M. G., Porsev, S. G., Levshakov, S. A., Reimers, D., Molaro, P.
Sensitivity coefficients to temporal variation of the fine-structure constant alpha for transitions between the fine-structure (FS) sub-levels of the ground states of C I, Si I, S I, Ti I, Fe I, N...
Levshakov, S. A., Reimers, D., Kozlov, M. G., Porsev, S. G., Molaro, P.
Aims. To obtain limits on the variation of the fine-structure constant alpha and the electron-to-proton mass ratio mu over different cosmological epochs. Methods. A new approach based on the...
Astronomy Astrophysics manuscript no. H4054 November 22, 2002 (2007)
Doi Will Be, P. Jakobsen, R. A. Jansen, S. Wagner, D. Reimers
We report the discovery of a quasar at z = 3.050 0.003, closely coincident in redshift with the isolated lowopacity feature seen near z # 3.056 in the otherwise black portion of the He ##...
HE 0515-4414 - an unusual sub-damped Ly alpha system revisited (2007)
Quast, R., Reimers, D., Baade, R.
Using STIS and VLT UVES observations we have examined the ionization, abundances, and differential dust depletion of metals, the kinematic structure, and the physical conditions in the molecular...
Porsev, S. G., Koshelev, K. V., Tupitsyn, I. I., Kozlov, M. G., Reimers, D., Levshakov, S. A.
Transition frequencies of Fe II ion are known to be very sensitive to variation of the fine structure constant \alpha. The resonance absorption lines of Fe II from objects at cosmological distances...
HE 0557-4840 - Ultra-Metal-Poor and Carbon-Rich (2007)
Norris, John E., Christlieb, N., Korn, A. J., Eriksson, K., Bessell, M. S., Beers, Timothy C., ...
We report the discovery and high-resolution, high S/N, spectroscopic analysis of the ultra-metal-poor red giant HE 0557-4840, which is the third most heavy-element deficient star currently known. Its...
High-Resolution Spectra Observed for SPY. II. DB and DBA Stars (2007)
Voss, B., Koester, D., Napiwotzki, R., Christlieb, N., Reimers, D.
We present a detailed spectroscopic analysis of the stars with helium-dominated spectra in the ESO Supernova Ia Progenitor Survey (SPY). Atmospheric parameters, masses, and abundances of trace...
Prause, N., Reimers, D., Fechner, C., Janknecht, E.
We present an analysis of the Lyman alpha forests of five quasar spectra in the near UV. Properties of the intergalactic medium (IGM) at an intermediate redshift interval (0.9 < z < 1.9) are studied....
Six New ZZ Ceti Stars from the SPY and the HQS Surveys (2007)
Voss, B., Koester, D., Østensen, R., Napiwotzki, R., Homeier, D., Reimers, D.
We report on the discovery of six new ZZ Ceti stars. They were selected as candidates based on preparatory photometric observations of objects from the Hamburg Quasar Survey (HQS), and based on the...
Levshakov, S. A., Molaro, P., Lopez, S., D'Odorico, S., Centurion, M., Bonifacio, P., ...
We probe the evolution of the fine-structure constant, alpha, with cosmic time. Accurate positions of the FeII lines 1608, 2382,and 2600 A are measured in the z = 1.84 absorption system from a...
Levshakov, S. A., Molaro, P., Lopez, S., D'Odorico, S., Centurion, M., Bonifacio, P., ...
Publicación ISI
Levshakov, S. A., Molaro, P., López, S., D'Odorico, S., Centurión, M., Bonifacio, P., ...
Publicación ISI
Binary White Dwarfs in the Supernova Ia Progenitor Survey. (2007)
Napiwotzki, R., Karl, C., Nelemans, G., Yungelson, L., Christlieb, N., Drechsel, H., ...
Six New ZZ Ceti Stars from the SPY and the HQS Surveys. (2007)
Voss, B., Koester, D., Ostensen, R., Napiwotzki, R., Homeier, D., Reimers, D.
The HeII Lyman alpha forest and the thermal state of the IGM (2006)
Recent analyses of the intergalactic UV background by means of the HeII Lyman alpha forest assume that HeII and HI absorption features have the same line widths. We omit this assumption to...
The evolution of Lyman alpha absorbers in the redshift range 0.5 < z < 1.9 (2006)
Janknecht, E., Reimers, D., López, S., Tytler, D.
We investigate the evolution and the statistical properties of the Ly alpha absorbers of the intergalactic medium (IGM) in the largely unexplored redshift range z = 0.5-1.9. We use high-resolution (R...
Spectral shape of the UV ionizing background and HeII absorption at redshifts 1.8 < z < 2.9 (2006)
Agafonova, I. I., Levshakov, S. A., Reimers, D., Fechner, C., Tytler, D., Simcoe, R. A., ...
The shape of the UV ionizing background is reconstructed from optically thin metal absorption-line systems identified in spectra of HE2347-4342, Q1157+3143, and HS1700+6416 in the redshift interval...
Fluctuations of the intergalactic UV background towards two lines of sight (2006)
We present a reanalysis of the HeII Lyman alpha absorption towards the quasars HS1700+6416 and HE2347-4342 using new high S/N, optical observations. An alternative analysis method is applied, which...
Stroeer, A., Heber, U., Lisker, T., Napiwotzki, R., Dreizler, S., Christlieb, N., ...
We address the origin and evolutionary status of hot subdwarf stars by studying the optical spectral properties of 58 subdwarf O (sdO) stars. Combining them with the results of our previously studied...
Frebel, A., Christlieb, N., Norris, J. E., Beers, T. C., Bessell, M. S., Rhee, J., ...
We present a sample of 1777 bright (9
The Evolution of Lyman alpha Absorbers in the Redshift Range 0.5 (2006)
Janknecht, E., Reimers, D., Lopez, S., Tytler, D.
We investigate the evolution and the statistical properties of the Lya absorbers of the intergalactic medium (IGM) in the largely unexplored redshift range z=0.5-1.9. We use high-resolution (R >...
The UV spectrum of HS1700+6416 I. Predicting the metal line content of the far UV spectrum (2006)
Fechner, C., Reimers, D., Songaila, A., Simcoe, R. A., Rauch, M., Sargent, W. L. W.
In preparation of a study of the HeII/HI ratio towards the bright QSO HS1700+6416, we predict the metal line content of the far-UV spectral range by modelling 18 metal absorption line systems with...
The UV spectrum of HS1700+6416 II. FUSE observations of the HeII Lyman alpha forest (2006)
Fechner, C., Reimers, D., Kriss, G. A., Baade, R., Blair, W. P., Giroux, M. L., ...
We present the far-UV spectrum of the quasar HS1700+6416 taken with FUSE. This QSO provides the second line of sight with the HeII absorption resolved into a Ly alpha forest structure. Since...
Discovery of eleven new ZZ Ceti stars. (2006)
Castanheira, B.G., Kepler, S.O., Mullally, F., Winget, D.E., Koester, D., Voss, B., ...
Discovery of seven ZZ Ceti stars using a new photometric selection method. (2006)
Voss, B., Koester, D., Ostensen, R., Kepler, S.O., Napiwotzki, R., Homeier, D., ...
Most precise single redshift bound to the variability of the fine-structure constant (2005)
Levshakov, S. A., Centurion, M., Molaro, P., D'Odorico, S., Reimers, D., Quast, R., ...
Verification of theoretical predictions of an oscillating behavior of the fine-structure constant, alpha, with cosmic time requires high precision measurements at individual redshifts, while in...
Discovery of eleven new ZZ Ceti stars (2005)
Castanheira, B. G., Kepler, S. O., Mullally, F., Winget, D. E., Koester, D., Voss, B., ...
We report the discovery of eleven new ZZ Cetis using telescopes at OPD (Observat\'orio do Pico dos Dias/LNA) in Brazil, the 4.1 m SOAR (Southern Astrophysical Research) telescope at Cerro Pachon,...
Most precise single redshift bound to Delta alpha/alpha (2005)
Levshakov, S. A., Centurion, M., Molaro, P., D'Odorico, S., Reimers, D., Quast, R., ...
Verification of theoretical predictions of an oscillating behavior of the fine-structure constant alpha with cosmic time requires high precision Delta alpha/alpha measurements at individual...
Spectral shape of the UV ionizing background and OVI absorbers at z ~ 1.5 towards HS0747+4259 (2005)
Reimers, D., Agafonova, I. I., Levshakov, S. A., Fechner, C., Tytler, D., ...
We report on high resolution spectra of the bright QSO HS0747+4259 (zem = 1.90, V = 15.8) observed to search for intermediate redshift OVI absorption systems. The spectra were obtained by means of...
HS 0146 1847 - a DAZB white dwarf of very unusual composition (2005)
Koester, D., Napiwotzki, R., Voss, B., Homeier, D., Reimers, D.
Intergalactic HeII absorption towards QSO 1157+3143 (2005)
Reimers, D., Fechner, C., Jakobsen, P., Tytler, D., Kirkman, D.
We report the discovery of a further line of sight allowing detection of HeII Ly alpha absorption by the intergalactic medium. A HST/STIS survey of 32 bright z ~ 3 quasars selected from the Hamburg...
Levshakov, S. A., Agafonova, I. I., Reimers, D., Fechner, C., Janknecht, E., Lopez, S.
HE0141-3932 (zem=1.80) is a bright blue radio-quite quasar which reveals an emission line spectrum with an unusually weak Ly-alpha line. In addition, large redshift differences (Delta z=0.05) are...
Two new ZZ Ceti pulsators from the HS and HE surveys (2005)
Silvotti, R., Voss, B., Bruni, I., Koester, D., Reimers, D., Napiwotzki, R., ...
We report the detection of nonradial g-mode oscillations in the DA white dwarfs HS1039+4112 (B=15.9) and HE1429-0343 (B=15.8) from time-series photometry made at the Loiano 1.5 m telescope. The two...
Binaries discovered by the SPY project. IV. Five single-lined DA double white dwarfs (2005)
Nelemans, G., Napiwotzki, R., Karl, C., Marsh, T. R., Voss, B., Roelofs, G., ...
We present results from our ongoing follow-up observations of double white dwarf binaries detected in the ESO SN Ia Progenitor SurveY (SPY). We discuss our observing strategy and data analysis and...
Barklem, P. S., Christlieb, N., Beers, T. C., Hill, V., Bessell, M. S., Holmberg, J., ...
We present the results of analysis of ``snapshot'' spectra of 253 metal-poor halo stars -3.8 < [Fe/H] < -1.5 obtained in the HERES survey. The spectra are analysed using an automated line profile...
Smette, A., Wisotzki, L., Ledoux, C., Garcet, O., Lopez, S., Reimers, D.
We present preliminary results from the Hamburg/ESO survey for Damped Ly-alpha (hereafter, DLA) Systems. This survey is characterized by (i) the good knowledge of the biases affecting the parent QSO...
The EUV variability of the luminous QSO HS 1700+6416 (2005)
Reimers, D., Schramm, J., Kriss, G. A., Shull, J. M.
We report on the first observations of variations in UV (intrinsic EUV 330 A) flux of the luminous QSO HS 1700+6416 (z=2.72) over a decade. The amplitude of variations increases from +/-0.1 mag in...
Metal Abundances in a Damped Lyman-alpha System Along Two Lines of Sight at z=0.93 (2005)
Lopez, S., Reimers, D., Gregg, M. D., Wisotzki, L., Wucknitz, O., Guzman, A.
We study metal abundances in the z=0.9313 damped Lya system observed in the two lines-of-sight, A and B, toward the gravitationally-lensed double QSO HE0512-3329. Spatially resolved STIS spectra...
Metal traces in white dwarfs of the SPY (ESO Supernova Ia Progenitor Survey) sample (2005)
Koester, D., Rollenhagen, K., Napiwotzki, R., Voss, B., Christlieb, N., Homeier, D., ...
HE 0141-3932: a bright QSO with an unusual emission line spectrum and associated absorption (2005)
Reimers, D., Janknecht, E., Fechner, C., Agafonova, I. I., Levshakov, S. A., Lopez, S.
HE 0141-3932 (zem = 1.80) is a bright blue radio-quite quasar with an unusually weak Ly-alpha emission line. Large redshift differences (Delta z = 0.05) are observed between high ionization and low...
Metal traces in white dwarfs of the SPY (ESO Supernova Ia Progenitor Survey) sample (2005)
Koester, D., Rollenhagen, K., Napiwotzki, R., Voss, B., Christenlieb, N., Homeier, D., ...
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
Binaries discovered by the SPY project IV. Five single-lined DA double white dwarfs. (2005)
Nelemans, G., Napiwotzki, R., Karl, C., Marsh, T.R., Voss, B., Roelofs, G., ...
Two new ZZ Ceti pulsators from the HS and HE surveys. (2005)
Silvotti, R., Voss, B., Bruni, I., Koester, D., Reimers, D., Napiwotzki, R., ...
DAZ White Dwarfs in the SPY Sample. (2005)
Koester, D., Rollenhagen, K., Napiwotzki, R., Voss, B., Christlieb, N., Homeier, D., ...
Subdwarf B Stars from the ESO Supernova Ia Progenitor Survey -- Observation versus Theory. (2005)
Lisker, T., Heber, U., Napiwotzki, R., Christlieb, N., Han, Z., Homeier, D., ...
New Results from the Supernova Ia Progenitor Survey. (2005)
Napiwotzki, R., Karl, C., Nelemans, G., Yungelson, L., Christlieb, N., Drechsel, H., ...
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
Werner, K., Rauch, T., Napiwotzki, R., Christlieb, N., Reimers, D., Karl, C.
Original paper can be found at: http://astrosociety.org/pubs/cs/328.html Copyright ASP
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
HE 0437-5439: an unbound hypervelocity main-sequence B-type star. (2005)
Edelmann, H., Napiwotzki, R., Heber, U., Christlieb, N., Reimers, D.
Original article can be found at: http://www.iop.org/EJ/journal/apjl Copyright American Astronomical Society DOI: 10.1086/498940 [Full text of this article is not available in the UHRA]
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
Quast, R., Reimers, D., Smette, A., Garcet, O., Ledoux, C., Lopez, S., ...
Spectroscopy of QSO absorption lines provides essential observational input for the study of nucleosynthesis and chemical evolution of galaxies at high redshift. But new observations may indicate...
A Concordance Model of the Lyman-alpha Forest at z = 1.95 (2004)
Jena, T., Norman, M. L., Tytler, D., Kirkman, D., Suzuki, N., Chapman, A., ...
We present 40 fully hydrodynamical numerical simulations of the intergalactic gas that gives rise to the Ly-alpha forest. We make artificial spectra from each and measure three output parameters: the...
Christlieb, N., Beers, T. C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
Identification of a DO White Dwarf and a PG1159 Star in the ESO SN Ia Progenitor Survey (SPY) (2004)
Werner, K., Rauch, T., Napiwotzki, R., Christlieb, N., Reimers, D., Karl, C. A.
We present high-resolution VLT spectra of a new DO white dwarf and a new PG1159 star, which we identified in the ESO SPY survey. The PG1159 star is a low-gravity, extremely hot (Teff=160,000 K, log...
The HeII Lyman alpha forest: evaluation of simulated data (2004)
Using an artificial HI Lyman alpha spectrum we simulate the corresponding HeII forest with fixed values of eta and a Doppler parameter consisting of a thermal and a turbulent part. In addition metal...
FUSE observations of the HeII Lyman alpha forest towards HS1700+6416 (2004)
Reimers, D., Fechner, C., Kriss, G., Shull, M., Baade, R., Moos, W., ...
We present FUSE observations of the HeII Lyman alpha forest in the redshift range 2.3 < z < 2.7 towards HS1700+6416. Between October 2002 and February 2003, the brightness of the QSO increased by a...
Evolution strategies applied to the problem of line profile decomposition in QSO spectra (2004)
Quast, R., Baade, R., Reimers, D.
We describe the decomposition of QSO absorption line ensembles applying an evolutionary forward modelling technique. The modelling is optimized using an evolution strategy (ES) based on a novel...
Lisker, T., Heber, U., Napiwotzki, R., Christlieb, N., Han, Z., Homeier, D., ...
We present the analysis of a high-resolution, high-quality sample of optical spectra for 76 subdwarf B (sdB) stars from the ESO Supernova Ia Progenitor Survey (SPY). Effective temperature, surface...
Identification of a DO white dwarf and a PG1159 star in the ESO SN Ia progenitor survey (SPY) (2004)
Werner, K., Rauch, T., Napiwotzki, R., Christlieb, N., Reimers, D., Karl, C. A.
We present high-resolution VLT spectra of a new helium-rich DO white dwarf and a new PG1159 star, which we identified in the ESO SPY survey. We performed NLTE model atmosphere analyses and found that...
Close binary EHB stars from SPY (2004)
Napiwotzki, R., Karl, C., Lisker, T., Heber, U., Christlieb, N., Reimers, D., ...
Double degenerates and progenitors of supernovae type Ia (2004)
Napiwotzki, R., Yungelson, L., Nelemans, G., Marsh, T. R., Leibundgut, B., Renzini, A., ...
We report on systematic radial velocity surveys for white dwarf - white dwarf binaries (double degenerates - DDs) including SPY (ESO Supernovae Ia progenitor survey) recently carried out at the VLT....
Close binary EHB stars from SPY (2004)
Napiwotzki, R., Karl, C. A., Lisker, T., Heber, U., Christlieb, N., Reimers, D., ...
We present the results of a radial velocity (RV) survey of 46 subdwarf B (sdB) and 23 helium-rich subdwarf O (He-sdO) stars. We detected 18 (39%) new sdB binary systems, but only one (4%) He-sdO...
Close binary white dwarfs and supernovae IA (2004)
Christlieb , N., Drechsel , H., Heber , U., Homeier , D., Karl , C., Koester , D., ...
Informamos sobre el estado actual de los surveys" de velocidades radiales para binarias de enanas blancas (degeneradas dobles - DDs) incluyendo SPY (Exploración ESO de progenitoras de supernovas Ia)...
Spectroscopic analysis of sdB stars from the ESO Supernova Ia Progenitor Survey (2004)
Lisker, T., Heber, U., Napiwotzki, R., Christlieb, N., Han, Z., Homeier, D., ...
Double Degenerate and Progenitors of Supernovae Type Ia. (2004)
Napiwotzki, R., Yungelson, L., Nelemans, G., Marsh, T.R., Leibundgut, B., Renzini, A., ...
R. Quast, D. Reimers, S. A. Levshakov
Probing the variability of the fine-structure constant with the VLT/UVES ⋆,⋆⋆
Spectroscopic analysis of sdB stars from the ESO Supernova Ia Progenitor Survey (2003)
Lisker, T., Heber, U., Napiwotzki, R., Christlieb, N., Reimers, D., Homeier, D.
We report on the analysis of high-resolution optical spectra for 77 subdwarf B (sdB) stars from the ESO Supernova Ia Progenitor Survey. Effective temperature, surface gravity, and photospheric helium...
Karl, C. A., Napiwotzki, R., Nelemans, G., Christlieb, N., Koester, D., Heber, U., ...
In the course of our search for double degenerate (DD) binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY - SPY) we...
Detection of molecular hydrogen at z=1.15 toward HE 0515-4414 (2003)
Reimers, D., Baade, R., Quast, R., Levshakov, S. A.
A new molecular hydrogen cloud is found in the sub-damped Ly-alpha absorber [log N(HI)=19.88+/-0.05] at the redshift z=1.15 toward the bright quasar HE0515-4414 (zem = 1.71). More than 30 absorption...
Engels, D., Reimers, D., Voges, W.
We present the Hamburg/RASS Catalogue (HRC) of optical identifications of X-ray sources at high-galactic latitude. The HRC includes all X-ray sources from the ROSAT Bright Source Catalogue (RASS-BSC)...
Photoionized OVI absorbers toward the bright QSO HE 0515-4414 (2003)
Levshakov, S. A., Agafonova, I. I., Reimers, D., Baade, R.
We report on detailed Monte Carlo inversion analysis of five OVI systems from the spectrum of the bright quasar HE 0515-4414 (z_e = 1.71). The associated system at z_a = 1.697 with the neutral...
Caught in the act: a helium-reionizing quasar near the line of sight to Q0302-003 (2002)
Jakobsen, P., Jansen, R. A., Wagner, S., Reimers, D.
We report the discovery of a quasar at z=3.050+/-0.003, closely coincident in redshift with the isolated low-opacity feature seen near z~3.056 in the otherwise black portion of the HeII Gunn-Peterson...
Search for double degenerate progenitors of supernovae type Ia with SPY (2002)
Napiwotzki, R., Christlieb, N., Drechsel, H., Heber, U., Homeier, D., ...
We report on a large survey for double degenerate (DD) binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (SN Ia Progenitor surveY - SPY). About 560...
Search for double degenerate progenitors of supernovae type Ia with SPY (2002)
Napiwotzki, R., Drechsel, H., Heber, U., Karl, C., Christlieb, N., ...
We report on a large survey for double degenerate (DD) binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY - SPY).
Double degenerates from the supernova Ia progenitor survey (SPY) (2002)
Karl, C., Napiwotzki, R., Heber, U., Lisker, T., Nelemans, G., Christlieb, N., ...
We report on follow-up observations of double degenerate (DD) white dwarfs from the Supernovae Ia Progenitor Survey (SPY). Orbital parameters of four systems, including a massive short period system,...
Napiwotzki, R., Koester, D., Nelemans, G., Yungelson, L., Christlieb, N., Renzini, A., ...
In the course of our search for double degenerate (DD) binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY - SPY) we...
Search for progenitors of supnernovae type Ia with SPY (2002)
Napiwotzki, R., Christlieb, N., Drechsel, H., Heber, U., Homeier, D., ...
We have started a large survey for double degenerate (DD) binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY - SPY). About...
Christlieb, N., Green, P. J., Wisotzki, L., Reimers, D.
We present a sample of 403 faint high latitude carbon (FHLC) stars selected from the digitized objective prism plates of the Hamburg/ESO Survey (HES). Because of the ~15 Angstroem spectral resolution...
Search for progenitors of supernovae type Ia with SPY (2001)
Napiwotzki, R., Christlieb, N., Drechsel, H., Heber, U., Homeier, D., ...
Search for progenitors of supernovae type Ia with SPY. (2001)
Napiwotzki, R., Christlieb, N., Drechsel, H., Hagen, H.J., Heber, U., Homeier, D., ...
‘The definitive version is available at www3.interscience.wiley.com .' Copyright WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/1521-3994(200112)322:5/63.0.CO;2-I [Full text of this...
The stellar content of the Hamburg/ESO survey. I. Automated selection of DA white dwarfs (2000)
Christlieb, N., Wisotzki, L., Reimers, D., Homeier, D., Koester, D., Heber, U.
We describe automatic procedures for the selection of DA white dwarfs in the Hamburg/ESO objective-prism survey (HES). For this purpose, and the selection of other stellar objects (e.g., metal-poor...
Mining the Digital Hamburg/ESO Objective Prism Survey (2000)
Christlieb, N., Wisotzki, L., Reimers, D.
We report on the exploitation of the stellar content of the Hamburg/ESO objective prism survey by quantitative selection methods, such as automatic spectral classification, and first results obtained.
Cool helium-rich white dwarfs from the Hamburg/ESO Survey (2000)
Friedrich, S., Koester, D., Christlieb, N., Reimers, D., Wisotzki, L.
We present an analysis of 40 cool helium-rich white dwarfs found in the Hamburg/ESO survey. They were selected for follow-up spectroscopy because of their U-B colour below -0.18, the absence of...
The Hamburg/RASS optical identification project (2000)
We use digitized Schmidt direct and prism plates taken for the northern hemisphere Hamburg Quasar Survey (HQS) to obtain optical identifications for all high galactic latitude X-ray sources in the...
The warm circumstellar envelope and wind of the G9 IIb star HR 6902 (2000)
Kirsch, T., Baade, R., Reimers, D.
IUE observations of the eclipsing binary system HR 6902 obtained at various epochs spread over four years indicate the presence of warm circumstellar material enveloping the G9 IIb primary. The...
Damped Lyman alpha systems at z=0.68 and z=1.15 towards HE 1122-1649 and HE 0515-4414 (2000)
Reimers, D., Tytler, D., Barlow, T., Burles, S.
Detailed analysis of the spectral lines from two low redshift damped Lyman alpha absorbers (DLA) confirms that they are a heterogeneous population. Both systems have low metal abundances of...
The Hamburg/ESO survey for bright QSOs. III. A large flux-limited sample of QSOs (2000)
Wisotzki, L., Christlieb, N., Bade, N., Beckmann, V., Koehler, T., Vanelle, C., ...
We present a new sample of 415 bright QSOs and Seyfert~1 nuclei drawn from the Hamburg/ESO survey (HES). The sample is spectroscopically 99 % complete and well-defined in terms of flux and redshift...
Finding the First Stars: The Hamburg/ESO Objective Prism Survey (1999)
Christlieb, N., Reimers, D., Wisotzki, L., Reetz, J., Gehren, T., Beers, T. C.
We report on a search for extremely metal-poor ([Fe/H]
Four magnetic DB white dwarfs discovered by the Hamburg/ESO survey (1998)
Reimers, D., Jordan, S., Beckmann, V., Christlieb, N., Wisotzki, L.
We report on seven peculiar faint blue stars found in the course of the Hamburg/ESO survey (HES) which appear to be magnetic white dwarfs (WDs) with non-hydrogen spectra. We show in particular that...
Reimers, D., Koehler, S., Wisotzki, L., Groote, D., Rodriguez-Pascual, P., Wamsteker, W.
We report on observations of redshifted HeII 304 A absorption in the QSO HE 2347-4342 (z=2.885, V=16.1) with the GHRS on board HST (FWHM=0.7 A). At the expected position of HeII 304 A absorption, HE...
The local luminosity function of QSOs and Seyfert 1 nuclei (1997)
Koehler, T., Groote, D., Reimers, D., Wisotzki, L.
We present the analysis of a new flux-limited sample of bright quasars and Seyfert 1 galaxies in an effective area of 611 square deg, drawn from the Hamburg/ESO survey. We confirm recent claims that...
Discovery of four white dwarfs with strong magnetic fields by the Hamburg/ESO Survey (1996)
Reimers, D., Jordan, S., Koester, D., Bade, N., Koehler, Th., Wisotzki, L.
Four magnetic white dwarfs have been found in the course of the Hamburg/ESO Survey for bright QSOs. The objects have been selected as QSO candidate on the basis of its blue continuum and the apparent...
Cuevas, P, García-Calvo, M, Carceller, F, Reimers, D, Zazo, M, Cuevas, B, ...
Acidic and basic fibroblast growth factors (FGFs) share a wide range of diverse biological activities. To date, low levels of FGF have not been correlated with a pathophysiologic state. We report...
Cuevas, P, García-Calvo, M, Carceller, F, Reimers, D, Zazo, M, Cuevas, B, ...
Acidic and basic fibroblast growth factors (FGFs) share a wide range of diverse biological activities. To date, low levels of FGF have not been correlated with a pathophysiologic state. We report...