2004A&A...417..853C


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.07CET04:08:12

2004A&A...417..853C - Astronomy and Astrophysics, volume 417, 853-871 (2004/4-3)

Probing the cosmological variation of the fine-structure constant: Results based on VLT-UVES sample.

CHAND H., SRIANAND R., PETITJEAN P. and ARACIL B.

Abstract (from CDS):

Development of fundamental physics relies on the constancy of various fundamental quantities such as the fine-structure constant. Detecting or constraining the possible time variations of these fundamental physical quantities is an important step toward a complete understanding of basic physics. High-quality absorption lines seen in the spectra of distant QSOs allow one to probe time variations of several of these quantities. Here we present the results from a detailed many-multiplet analysis, to detect the possible variation of the fine-structure constant, performed using high signal-to-noise ratio, (∼70 per pixel), high spectral resolution (R≥45000) observations of 23 Mg II systems detected toward 18 QSOs in the redshift range 0.4≤z≤2.3 obtained using UVES at the VLT. We validate our procedure and define the selection criteria that will avoid possible systematics using a detailed analysis of a simulated data set. The spectra of Mg II doublets and Fe II multiplets are generated considering variations in α and specifications identical to that of our UVES spectra. We show that our Voigt profile fitting code recovers the variation in α very accurately when we use single component systems and multiple-component systems that are not heavily blended. Spurious detections are frequently seen when we use heavily blended systems or systems with very weak lines. Thus we avoided these system while analysing the UVES data. To make the analysis transparent and accessible to the community for critical scrutiny, all the steps involved in the analysis are presented in detail. The weighted mean value of the variation in α obtained from our analysis over the redshift range 0.4≤z≤2.3 is Δα/α = (-0.06±0.06)x10–5. The median redshift of our sample is 1.55 and corresponds to a look-back time of 9.7Gyr in the most favored cosmological model today. The 3σ upper limit on the time variation of α is -2.5x10–16/yr≤(Δα/αΔt)≤+1.2x10–16yr–1. To our knowledge this is the strongest constraint from quasar absorption line studies to till date.

Abstract Copyright:

Journal keyword(s): galaxies: quasars: absorption lines - cosmology: observations

Nomenclature: Table 2: [CSP2004] QSO JHHMM+DDMM abs N.NNNN N=50.

Simbad objects: 15

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Number of rows : 15

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 QSO J0003-2323 QSO 00 03 44.9144470879 -23 23 55.075352888     16.7     ~ 69 0
2 QSO B0002-422 QSO 00 04 48.2718823544 -41 57 28.150311306   17.44 17.21     ~ 155 0
3 QSO B0109-353 QSO 01 11 43.6321355926 -35 03 00.586979841   16.6 16.9     ~ 72 0
4 QSO B0122-379 QSO 01 24 17.3723276055 -37 44 22.919153842     17.1     ~ 113 0
5 QSO J0153-4311 QSO 01 53 27.1919509912 -43 11 38.096734050     16.80     ~ 45 0
6 QSO B0237-2322 QSO 02 40 08.1742481040 -23 09 15.727160394   16.78 16.63     ~ 483 0
7 QSO B0329-385 QSO 03 31 06.3780192488 -38 24 04.653743031   17.63 16.92     ~ 75 0
8 PHL 4444 QSO 03 31 08.9205312901 -25 24 43.264751845   17.82 17.51 18.2   ~ 94 1
9 QSO J0455-4216 QSO 04 55 23.0623318803 -42 16 17.398158654   17.77 17.06     ~ 133 0
10 QSO B0940-1050 QSO 09 42 53.5076745009 -11 04 25.929146122   16.96 16.6 16.6   ~ 87 0
11 QSO J1344-1035 QSO 13 44 27.0638968862 -10 35 41.748550205     17.1     ~ 47 0
12 QSO B1448-232 QSO 14 51 02.5094965667 -23 29 31.105639377   17.13 16.96     ~ 121 2
13 QSO B2126-15 QSO 21 29 12.17589777 -15 38 41.0413097   17.61 17.3 17.3   ~ 472 1
14 QSO J2220-2803 QSO 22 20 06.7586653848 -28 03 23.466203761     16.0 16.10   ~ 89 0
15 QSO B2347-4342 QSO 23 50 34.2595236845 -43 25 59.680334378   16.3 16.3     ~ 160 0

    Equat.    Gal    SGal    Ecl

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2021.03.07-04:08:12

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