Stringent bounds to spatial variations of the electron-to-proton mass ratio in the Milky Way (2009)
Molaro, Paolo, Levshakov, Sergei A., Kozlov, MiKhail G.
The ammonia method to probe variations of the electron-to-proton mass ratio, Delta_mu/mu, is applied for the first time to dense prestellar molecular clouds in the Milky Way. Carefully selected...
Cosmic dynamics in the era of Extremely Large Telescopes (2008)
Liske, Jochen, Grazian, Andrea, Vanzella, Eros, Dessauges, Miroslava, Viel, Matteo, Pasquini, Luca, ...
The redshifts of all cosmologically distant sources are expected to experience a small, systematic drift as a function of time due to the evolution of the Universe's expansion rate. A measurement of...
Cosmic dynamics in the era of Extremely Large Telescopes (2008)
Liske, Jochen, Grazian, Andrea, Vanzella, Eros, Dessauges, Miroslava, Viel, Matteo, Pasquini, Luca, ...
The redshifts of all cosmologically distant sources are expected to experience a small, systematic drift as a function of time due to the evolution of the Universe's expansion rate. A measurement of...
Cosmic dynamics in the era of Extremely Large Telescopes (2008)
Liske, Jochen, Grazian, Andrea, Vanzella, Eros, Dessauges, Miroslava, Viel, Matteo, Pasquini, Luca, ...
The redshifts of all cosmologically distant sources are expected to experience a small, systematic drift as a function of time due to the evolution of the Universe's expansion rate. A measurement of...
Cosmic dynamics in the era of Extremely Large Telescopes (2008)
Liske, Jochen, Grazian, Andrea, Vanzella, Eros, Dessauges, Miroslava, Viel, Matteo, Pasquini, Luca, ...
The redshifts of all cosmologically distant sources are expected to experience a small, systematic drift as a function of time due to the evolution of the Universe's expansion rate. A measurement of...
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...
THE ASTROPHYSICAL JOURNAL, 565 696719, 2002 February 1 (2007)
The American Astronomical, Sergei A. Levshakov, Miroslava Dessauges-zavadsky, Sandro Dodorico, Paolo Molaro
We have detected in high-resolution spectra of the quasar Q0347[3819 obtained with the UV-Visual Echelle Spectrograph (UVES) at the VLT/Kueyen telescope over 80 absorption features in the Lyman and...
THE ASTROPHYSICAL JOURNAL, 549 9099, 2001 March 1 (2007)
The American Astronomical, Paolo Molaro, Sergei A. Levshakov, Sandro Dodorico, Piercarlo Bonifacio, Miriam Centurio N
The UV resonance transitions of neutral argon, Ar I j1066, and of singly ionized phosphorus, P II j963, originated in the damped Lya system (DLA) at toward QSO 0000[2620, have been z \ 3.3901...
The CODEX-ESPRESSO experiment: cosmic dynamics, fundamental physics, planets and much more (2007)
Cristiani, Stefano, Avila, Gerardo, Bonifacio, Piercarlo, Bouchy, Francois, Carswell, B., D'Odorico, Sandro D., ...
CODEX, a high-resolution, super-stable spectrograph to be fed by the E-ELT, the most powerful telescope ever conceived, will for the first time provide the possibility of directly measuring the...
The CODEX-ESPRESSO experiment: cosmic dynamics, fundamental physics, planets and much more (2007)
Cristiani, Stefano, Avila, Gerardo, Bonifacio, Piercarlo, Bouchy, Francois, Carswell, B., D'Odorico, Sandro D., ...
CODEX, a high-resolution, super-stable spectrograph to be fed by the E-ELT, the most powerful telescope ever conceived, will for the first time provide the possibility of directly measuring the...
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...
Exploring variations in the fundamental constants with ELTs: the CODEX spectrograph on OWL (2005)
Molaro, Paolo, Murphy, Michael T., Levshakov, Sergei A.
Cosmological variations in the fine structure constant, α, can be probed through precise velocity measurements of metallic absorption lines from intervening gas clouds seen in spectra of...
Exploring variations in the fundamental constants with ELTs: the CODEX spectrograph on OWL (2005)
Molaro, Paolo, Murphy, Michael T., Levshakov, Sergei A.
Cosmological variations in the fine structure constant, α, can be probed through precise velocity measurements of metallic absorption lines from intervening gas clouds seen in spectra of...
Exploring variations in the fundamental constants with ELTs: the CODEX spectrograph on OWL (2005)
Molaro, Paolo, Murphy, Michael T., Levshakov, Sergei A.
Cosmological variations in the fine structure constant, α, can be probed through precise velocity measurements of metallic absorption lines from intervening gas clouds seen in spectra of...
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...
Metal Abundances and Kinematics of the Ly-alpha absorbers (2003)
Both high resolution spectra of QSOs observed at the 8-10m telescopes and advanced methods of data analysis are crucial for accurate measurements of the chemical composition and physical parameters...
Astrophysical constraints on hypothetical variability of fundamental constants (2003)
(Abridged) Many-multiplet (MM) method applied to three inhomogeneous samples of Keck/HIRES quasar absorption spectra gives a shift in the value of the fine-structure constant of Delta alpha/alpha =...
Molaro, Paolo, Levshakov, Sergei A., D'Odorico, Sandro, Bonifacio, Piercarlo, Centurion, Miriam
The UV resonance transitions of neutral argon ArI 1066 A, and of singly ionized phosphorus PII 963 A, originated in the damped Ly_alpha system (DLA) at zabs = 3.3901 towards QSO 0000--2620 have been...
Monte Carlo inversion of hydrogen and metal lines from QSO absorption spectra (2000)
Levshakov, Sergei A., Agafonova, Irina I., Kegel, Wilhelm H.
A new method, based on the simulated annealing algorithm and aimed at the inverse problem in the analysis of intergalactic (interstellar) complex spectra of hydrogen and metal lines, is presented. We...
The deuterium abundance in QSO absorption systems: a mesoturbulent approach (2000)
A new method, based on simulated annealing technique and aimed at the inverse problem in the analysis of intergalactic or interstellar complex spectra of hydrogen and metal lines, is outlined. We...
Monte Carlo inversion of hydrogen and metal lines from QSO absorption spectra (2000)
Sergei A. Levshakov, Irina I. Agafonova, Wilhelm H. Kegel
. A new method, based on the simulated annealing algorithm and aimed at the inverse problem in the analysis of intergalactic (interstellar) complex spectra of hydrogen and metal lines, is presented....
On the measurement of kinetic temperature in high redshift galactic halos (1999)
Levshakov, Sergei A., Kegel, Wilhelm W.
We consider the deconvolution of the thermal and the turbulent profiles for a pair of ions with different atomic weights under the condition that the lines are formed in an absorbing medium with...
Deuterium to hydrogen towards QSO 1009+2956 from a mesoturbulent model (1998)
Levshakov, Sergei A., Tytler, David, Burles, Scott
We present a new analysis of the deuterium absorption at z = 2.504 towards the quasar Q1009+2956 using the mesoturbulent model which accounts for possible correlations in the large scale velocity...
Levshakov, Sergei A., Takahara, Fumio, Agafonova, Irina I.
We present a new method for recovering the kinetic temperature of the intervening diffuse gas to an accuracy of 10%. The method is based on the comparison of unsaturated absorption-line profiles of...
A uniform primordial deuterium abundance stemmed from QSO observations (1998)
The discordance between `low' and `high' primordial D/H measurements can be considerably reduced if the analysis of the H+D profiles accounts for the correlated velocity field of bulk motion. We have...
The D/H ratio at z = 3.57 toward Q 1937-1009 (1998)
Levshakov, Sergei A., Kegel, Wilhelm H., Takahara, Fumio
Deuterium abundance re-measurements by Burles and Tytler (1998; hereafter BT) yielded D/H = (3.3 +/- 0.3) 10^{-5} and the robust upper limit D/H < 3.9 10^{-5} from the z_a = 3.572 system toward...
The D/H ratio at z=0.7 toward Q 1718+4807 (1998)
Levshakov, Sergei A., Kegel, Wilhelm H., Takahara, Fumio
The apparent discrepancy between low and high D abundances derived from QSO spectra may be caused by spatial correlations in the stochastic velocity field. If one accounts for such correlations, one...
Primordial Deuterium Abundance Measurements (1997)
Levshakov, Sergei A., Kegel, Wilhelm H., Takahara, Fumio
Deuterium abundances measured recently from QSO absorption-line systems lie in the range from 3 10^{-5} to 3 10^{-4}, which shed some questions on standard big bang theory. We show that this...
The primordial deuterium abundance : problems and prospects (1997)
Levshakov, Sergei A., Takahara, Fumio, Kegel, Wilhelm H.
The current status of extragalactic deuterium abundance is discussed using two examples of `low' and `high' D/H measurements. We show that the discordance of these two types of D abundances may be a...
Forest Clouds, Wilhelm H. Kegel, Sergei A. Levshakov, T Kin
H 0 = 70 km s \Gamma1 Mpc \Gamma1 . The value of n(HI) was estimated from the continuum depression DA at z = 3 observed in low resolution spectra, T kin corresponds to the width of the narrowest...