Constraints on Changes in Fundamental Constants from a Cosmologically Distant OH Absorber or Emitter

Kanekar, Nissim; Carilli, C. L.; Langston, G. I.; Rocha, G.; Combes, F.; Subrahmanyan, R.; Stocke, J. T.; Menten, K. M.; Briggs, F.; Wiklind, T.

doi:10.1103/physrevlett.95.261301

Cited by 125 publications

(142 citation statements)

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“…Molecular absorption has also been detected in the galaxies hosting the radio sources B3 1504+377 at z = 0.67 (in CO, HCO + , HCN, and HNC; Wiklind & Combes 1996b), PKS 1413+135 at z = 0.25 (in CO, HCO + , HCN, HNC, and CN; Wiklind & Combes 1997), and PKS 0132−097 at z = 0.76 (although only in OH; Kanekar et al 2005). However, the weakness of the background radio continuum sources, narrower linewidths and smaller column densities of absorbing gas than the two absorbers toward PKS 1830−211 and B 0218+357, ensures that it is difficult to perform a deep inventory of their molecular constituents with current instruments.…”

Section: Introductionmentioning

confidence: 94%

Molecules atz= 0.89

Müller

Beelen

Guèlin

et al. 2011

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We present the results of a 7 mm spectral survey of molecular absorption lines originating in the disk of a z = 0.89 spiral galaxy located in front of the quasar PKS 1830−211. Our survey was performed with the Australia Telescope Compact Array and covers the frequency interval 30-50 GHz, corresponding to the rest-frame frequency interval 57-94 GHz. A total of 28 different species, plus 8 isotopic variants, were detected toward the south-west absorption region, located about 2 kpc from the center of the z = 0.89 galaxy, which therefore has the largest number of detected molecular species of any extragalactic object so far. The results of our rotation diagram analysis show that the rotation temperatures are close to the cosmic microwave background temperature of 5.14 K that we expect to measure at z = 0.89, whereas the kinetic temperature is one order of magnitude higher, indicating that the gas is subthermally excited. The molecular fractional abundances are found to be in-between those in typical Galactic diffuse and translucent clouds, and clearly deviate from those observed in the dark cloud TMC 1 or in the Galactic center giant molecular cloud Sgr B2. The isotopic ratios of carbon, nitrogen, oxygen, and silicon deviate significantly from the solar values, which can be linked to the young age of the z = 0.89 galaxy and a release of nucleosynthesis products dominated by massive stars. Toward the north-east absorption region, where the extinction and column density of gas is roughly one order of magnitude lower than toward the SW absorption region, only a handful of molecules are detected. Their relative abundances are comparable to those in Galactic diffuse clouds. We also report the discovery of several new absorption components, with velocities spanning between −300 and +170 km s −1 . Finally, the line centroids of several species (e.g., CH 3 OH, NH 3 ) are found to be significantly offset from the average velocity. If caused by a variation in the proton-to-electron mass ratio μ with redshift, these offsets yield an upper limit | Δμ μ | < 4×10 −6 , which takes into account the kinematical noise produced by the velocity dispersion measured from a large number of molecular species.

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Section: Introductionmentioning

confidence: 94%

Molecules atz= 0.89

Müller

Beelen

Guèlin

et al. 2011

A&A

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“…For example, extensive studies of atomic and molecular spectra of gas clouds in the distant Universe are currently undertaken to search for a difference of these parameters compared to today's values (see e.g. [7][8][9][10][11] and references therein). Also, some differences in Big Bang nucleosynthesis data and calculations can be naturally explained by a variation of fundamental constants [12,13].…”

Section: Spin-off To Other Fields (Outside Fundamental Physics)mentioning

confidence: 99%

Einstein Gravity Explorer–a medium-class fundamental physics mission

et al. 2008

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The Einstein Gravity Explorer mission (EGE) is devoted to a precise measurement of the properties of space-time using atomic clocks. It tests one of the most fundamental predictions of Einstein's Theory of General Relativity, the gravitational redshift, and thereby searches for hints of quantum effects in gravity, exploring one of the most important and challenging frontiers in fundamental physics. The primary mission goal is the measurement of the gravitational redshift with an accuracy up to a factor 10 4 higher than the best current result. The mission is based on a satellite carrying cold atombased clocks. The payload includes a cesium microwave clock (PHARAO), an optical clock, a femtosecond frequency comb, as well as precise microwave time transfer systems between space and ground. The tick rates of the clocks are continuously compared with each other, and nearly continuously with clocks on earth, during the course of the 3-year mission. The highly elliptic orbit of the satellite is optimized for the scientific goals, providing a large variation in the gravitational potential between perigee and apogee. Besides the fundamental physics results, as secondary goals EGE will establish a global

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“…Wiklind & Combes 1995, 1996a, 1998Kanekar et al 2005). Among these, three absorption systems are caused by a galaxy lying on the line-of-sight of a quasar and acting as a gravitational lens.…”

Section: Introductionmentioning

confidence: 99%

Distribution of the molecular absorption in front of the quasar B0218+357

Müller¹,

Guèlin

Combes

et al. 2007

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The line of sight to the quasar B0218+357, one of the most studied lensed systems, intercepts a z = 0.68 spiral galaxy, which splits its image into two main components A and B, separated by ca. 0.3 , and gives rise to molecular absorption. Although the main absorption component has been shown to arise in front of image A, it is not established whether some absorption from other velocity components is also occuring in front of image B. To tackle this question, we have observed the HCO + (2-1) absorption line during the commissioning phase of the new very extended configuration of the Plateau de Bure Interferometer, in order to trace the position of the absorption as a function of frequency. Visibility fitting of the self-calibrated data allowed us to achieve position accuracy between ∼12 and 80 mas per velocity component. Our results clearly demonstrate that all the different velocity components of the HCO + (2-1) absorption arise in front of the south-west image A of the quasar. We estimate a flux ratio f A / f B = 4.2 +1.8 −1.0 at 106 GHz.

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Constraints on Changes in Fundamental Constants from a Cosmologically Distant OH Absorber or Emitter

Cited by 125 publications

References 20 publications

Molecules atz= 0.89

Molecules atz= 0.89

Einstein Gravity Explorer–a medium-class fundamental physics mission

Distribution of the molecular absorption in front of the quasar B0218+357

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