scholarly journals H2/HD molecular data for analysis of quasar spectra in search of varying constants

2019 ◽  
Vol 622 ◽  
pp. A127 ◽  
Author(s):  
W. Ubachs ◽  
E. J. Salumbides ◽  
M. T. Murphy ◽  
H. Abgrall ◽  
E. Roueff
Keyword(s):  
Vacuum Ultraviolet ◽  
High Redshift ◽  
Sensitivity Coefficient ◽  
Molecular Data ◽  
Oscillator Strengths ◽  
Absorption Lines ◽  
Electron Mass ◽  
Mass Ratio ◽  
Quasar Spectra ◽  
Varying Constants

Context. Absorption lines of H2 and HD molecules observed at high redshift in the line of sight towards quasars are a test ground to search for variation of the proton-to-electron mass ratio μ. For this purpose, results from astronomical observations are compared with a compilation of molecular data of the highest accuracy, obtained in laboratory studies as well as in first-principles calculations. Aims. A comprehensive line list is compiled for H2 and HD absorption lines in the Lyman (B1Σu+ − X1Σg+) and Werner (C1Πu − X1Σg+) band systems up to the Lyman cutoff at 912 Å. Molecular parameters listed for each line i are the transition wavelength λi, the line oscillator strength fi, the radiative damping parameter of the excited state Γi, and the sensitivity coefficient Ki for a variation of the proton-to-electron mass ratio. Methods. The transition wavelengths λi for the H2 and HD molecules are determined by a variety of advanced high-precision spectroscopic experiments involving narrowband vacuum ultraviolet lasers, Fourier-transform spectrometers, and synchrotron radiation sources. Results for the line oscillator strengths fi, damping parameters Γi, and sensitivity coefficients Ki are obtained in theoretical quantum chemical calculations. Results. A new list of molecular data is compiled for future analyses of cold clouds of hydrogen absorbers, specifically for studies of μ-variation from quasar data. The list is applied in a refit of quasar absorption spectra of B0642–5038 and J1237+0647 yielding constraints on a variation of the proton-to-electron mass ratio Δμ/μ consistent with previous analyses.

scholarly journals New Limit on Space-Time Variations in the Proton-to-Electron Mass Ratio from Analysis of Quasar J110325-264515 Spectra

Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 344
Author(s):  
T. D. Le
Keyword(s):  
Fine Structure ◽  
Structure Constant ◽  
Space Time ◽  
Fine Structure Constant ◽  
Electron Mass ◽  
Mass Ratio ◽  
Quasar Spectra ◽  
Time Variations ◽  
Using Data ◽  
The Universe

Astrophysical tests of current values for dimensionless constants known on Earth, such as the fine-structure constant, α , and proton-to-electron mass ratio, μ = m p / m e , are communicated using data from high-resolution quasar spectra in different regions or epochs of the universe. The symmetry wavelengths of [Fe II] lines from redshifted quasar spectra of J110325-264515 and their corresponding values in the laboratory were combined to find a new limit on space-time variations in the proton-to-electron mass ratio, ∆ μ / μ = ( 0.096 ± 0.182 ) × 10 − 7 . The results show how the indicated astrophysical observations can further improve the accuracy and space-time variations of physics constants.

scholarly journals New limit on a varying proton-to-electron mass ratio from high-resolution optical quasar spectra

2009 ◽  
Vol 5 (H15) ◽  
pp. 321-321
Author(s):  
A. L. Malec ◽  
R. Buning ◽  
M. T. Murphy ◽  
N. Milutinovic ◽  
S. L. Ellison ◽  
...  
Keyword(s):  
Optical Spectrum ◽  
Resolving Power ◽  
Electron Mass ◽  
Mass Ratio ◽  
Large Telescope ◽  
Relative Deviation ◽  
Quasar Spectra ◽  
Very Large Telescope ◽  
Free Parameters ◽  
First Time

AbstractMolecular transitions recently discovered at redshift zabs=2.059 toward the bright background quasar J2123-0050 are analysed to limit cosmological variation in the proton-to-electron mass ratio, μ ≡ mp/me. Observed with the Keck telescope, the optical spectrum has the highest resolving power and largest number (86) of H2 transitions in such analyses so far. Also, (7) HD transitions are used for the first time to constrain μ-variation. These factors, and an analysis employing the fewest possible free parameters, strongly constrain μ's relative deviation from the current laboratory value: Δμ/μ =(+5.6±5.5stat±2.7sys)×10−6. This is the first Keck result to complement recent constraints from three systems at zabs>2.5 observed with the Very Large Telescope.

Observational estimate of the partial covering probability of quasar emission regions by distant H2 absorption clouds

2020 ◽  
Vol 493 (4) ◽  
pp. 5743-5760
Author(s):  
V V Klimenko ◽  
P Petitjean ◽  
A V Ivanchik
Keyword(s):  
High Redshift ◽  
Absorption Lines ◽  
High Spectral Resolution ◽  
Continuum Source ◽  
Partial Coverage ◽  
Reverberation Mapping ◽  
Quasar Spectra ◽  
Observational Estimate ◽  
Partial Covering ◽  
Case Part

ABSTRACT We have searched high spectral resolution spectra of quasars known to exhibit high redshift (z > 1.7) intervening H2-bearing damped Lyman-α (DLA) systems for partial coverage of the quasar emission by intervening H2 clouds. Partial coverage manifests itself by the presence of non-zero residual flux in the core of saturated H2 absorption lines. The residual flux can be observed either only at the bottom of absorption lines redshifted on top of quasar emission lines, in which case part of the broad line region (BLR) is not covered, or in all absorption lines, in case some continuum source is not covered. Among 35 H2 absorption clouds in 14 quasar spectra obtained with the VLT-UVES or Keck-HIRES spectrographs, we detect partial coverage of the BLR for 13 clouds. This result suggests that the probability of partial coverage of the QSO BLR by a distant H2 absorption cloud is about 40 per cent. For four systems towards Q 0013−0029, Q 0405−4418, Q 0812+3208, and J 2100−0641, partial coverage is detected for the first time. We determine the theoretical probability of partial coverage of the BLR by a distant H2 cloud as a function of the ratio between the cloud and the BLR sizes. Using this model, we obtain an estimate of the characteristic BLR radius of $50^{+19}_{-23}\,\rm{light \,days}$. This is similar to the estimate of the BLR size obtained by reverberation-mapping analysis $({\sim}100\,\rm{light\, days})$.

scholarly journals Evolution of the EUV Background from Quasar Absorption Line Studies

1996 ◽  
Vol 168 ◽  
pp. 237-244
Author(s):  
Jill Bechtold
Keyword(s):  
Ionizing Radiation ◽  
Absorption Line ◽  
Radiation Field ◽  
Proximity Effect ◽  
Reasonable Agreement ◽  
Extreme Ultraviolet ◽  
High Redshift ◽  
Absorption Lines ◽  
Quasar Absorption Lines ◽  
Quasar Spectra

The integrated extreme ultraviolet (EUV) radiation from quasars and other high redshift sources provides an ambient ionizing radiation field which may photoionize the gas seen as quasar absorption lines. In particular, the observed evolution of the Lyα forest clouds probably results in part from the evolution of the EUV metagalactic field. Estimates of the EUV field as a function of redshift can be made from measuring the “proximity effect” in quasar spectra; uncertainties in these estimates may be large. Given the uncertainties, the estimated EUV field at z≈3 derived from the proximity effect is in reasonable agreement with the expected contribution from luminous quasars.

Oscillator Strength Measurements in the Vacuum-Ultraviolet by the Emission Method

1988 ◽  
Vol 102 ◽  
pp. 353-356
Author(s):  
C. Goldbach ◽  
G. Nollez
Keyword(s):  
Oscillator Strength ◽  
Vacuum Ultraviolet ◽  
Oscillator Strengths ◽  
Emission Method ◽  
Absolute Scale ◽  
Good Agreement

AbstractThe principles and the realization of an experiment devoted to oscillator strength measurements in the vacuum-ultraviolet by the emission method are briefly presented. The results obtained for the strong multiplets of neutral nitrogen and carbon in the 1200-2000 Å range yield an absolute scale of oscillator strengths in good agreement with the most recent calculations.

scholarly journals Accurate prediction of H3O+and D3O+sensitivity coefficients to probe a variable proton-to-electron mass ratio

2015 ◽  
Vol 454 (3) ◽  
pp. 2292-2298 ◽  
Author(s):  
A. Owens ◽  
S. N. Yurchenko ◽  
O. L. Polyansky ◽  
R. I. Ovsyannikov ◽  
W. Thiel ◽  
...  
Keyword(s):  
Accurate Prediction ◽  
Electron Mass ◽  
Mass Ratio ◽  
Sensitivity Coefficients

Analysis of Absorption Lines in Quasar Spectra

1989 ◽  
pp. 179-185
Author(s):  
V. Müller ◽  
J. P. Mücket ◽  
H. J. Haubold ◽  
S. Gottlöber
Keyword(s):  
Absorption Lines ◽  
Quasar Spectra

scholarly journals The Uehling correction to the energy levels in a pionic atom

2006 ◽  
Vol 84 (2) ◽  
pp. 107-113 ◽  
Author(s):  
S G Karshenboim ◽  
E Yu. Korzinin ◽  
V G Ivanov
Keyword(s):  
Free Electron ◽  
Vacuum Polarization ◽  
Energy Levels ◽  
Analytic Form ◽  
Electron Mass ◽  
Mass Ratio ◽  
Pionic Atom ◽  
Closed Analytic Form

We consider a correction to energy levels in a pionic atom induced by the Uehling potential, i.e., by a free electron vacuum-polarization loop. The calculation is performed for circular states (l = n–1). The result is obtained in a closed analytic form as a function of Zα and the pion-to-electron mass ratio. Certain asymptotics of the result are also presented.PACS Nos.: 12.20.Ds, 36.10.Gv

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