yoospot.blogg.se - Gravitational redshift galaxy

hydrogen/helium), unless you postulate that the laws of physics themselves are different far away from us, which has its own set of problems. But how would you create a star that is redder? Starlight is well-understood (see main sequence), and you can't get stars that are that much redder from the same building blocks as stars around us (i.e. Maybe stars in faraway galaxies are just redder.Problem with this is, how why are those galaxies receding from us? Did we kick them? If so, how? See also Copernican principle. This makes the redshift a pure doppler redshift.

Maybe space is static but everything else is receding from us.

This is the tired light hypothesis, which is generally regarded as falsified.

Maybe the light is losing energy because it is traveling through (non-expanding) space.

See this 2011 paper, for which the gravitational redshift of galaxy clusters turns out to be a few km/s, not nearly enough to match cosmological redshift (which is many orders of magnitude larger). The effect turns out to be too small to account for the observed redshift. This is something that can be checked, because the equations governing gravitational redshift are well-known.

Maybe the light is losing energy because it is climbing out of a potential well (aka gravitational redshift).

If we assume that the observed redshift is not due to expansion, then something else must be causing it. Overall, our results are consistent with both GR and DGP predictions, while they are in marginal disagreement with the predictions of the considered f( R) strong field model.There're a few ways to do it. We recover an integrated gravitational redshift signal of −11.4 ± 3.3 km s −1, which is in agreement, within the errors, with past literature works.Ĭonclusions. We clearly detect the gravitational redshift effect in the exploited cluster member catalogue. Finally, we investigated the systematic uncertainties that possibly affect the analysis. A new statistical procedure was used to fit the measured gravitational redshift signal, and thus to discriminate among the considered gravity theories. We compared our measurements with the theoretical predictions of three different gravity theories: general relativity (GR), the f( R) model, and the Dvali–Gabadadze–Porrati (DGP) model. We find that this centre definition provides a better estimation of the centre of the cluster gravitational potential wells, relative to simply assuming the brightest cluster galaxies as the cluster centres, as done in past literature works.

We accurately estimated the cluster centres, computing them as the average of angular positions and redshifts of the closest galaxies to the brightest cluster galaxies. We analysed the velocity distribution of the cluster member galaxies to make new measurements of the gravitational redshift effect inside galaxy clusters. We considered a spectroscopic sample of 3058 galaxy clusters, with a maximum redshift of 0.5 and masses between 10 14 − 10 15 M ⊙. We exploit spectroscopic galaxy and galaxy cluster samples extracted from the latest releases of the Sloan Digital Sky Survey (SDSS) to derive new constraints on the gravity theory. The peculiar velocity distribution of cluster member galaxies provides a powerful tool to directly investigate the gravitational potentials within galaxy clusters and to test the gravity theory on megaparsec scales.Īims. INAF – Osservatorio Astrofisico di Arcetri, Largo E. INFN – Sezione di Roma Tre, Via della Vasca Navale 84, 00146 Rome, Italy INFN – Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italyĭipartimento di Fisica, Università degli Studi Roma Tre, Via della Vasca Navale 84, 00146 Rome, Italy INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy Moscardini 1 ,3 ,4ĭipartimento di Fisica e Astronomia “Augusto Righi” – Alma Mater Studiorum Università di Bologna, Via Piero Gobetti 93/2, 40129 Bologna, ItalyĮ-mail: Univ., CNRS/IN2P3, CPPM, 163 Avenue de Luminy, Case 902, 13288 Marseille Cedex 09, France Astronomical objects: linking to databasesĭ.Including author names using non-Roman alphabets.Suggested resources for more tips on language editing in the sciences

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