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  2. Redshift - Wikipedia

    en.wikipedia.org/wiki/Redshift

    The redshift observed in astronomy can be measured because the emission and absorption spectra for atoms are distinctive and well known, calibrated from spectroscopic experiments in laboratories on Earth. When the redshift of various absorption and emission lines from a single astronomical object is measured, z is found

  3. Redshift survey - Wikipedia

    en.wikipedia.org/wiki/Redshift_survey

    In astronomy, a redshift survey is a survey of a section of the sky to measure the redshift of astronomical objects: usually galaxies, but sometimes other objects such as galaxy clusters or quasars. Using Hubble's law, the redshift can be used to estimate the distance of an object from Earth. By combining redshift with angular position data, a ...

  4. Glossary of astronomy - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_astronomy

    This glossary of astronomy is a list of definitions of terms and concepts relevant to astronomy and cosmology, their sub-disciplines, and related fields. Astronomy is concerned with the study of celestial objects and phenomena that originate outside the atmosphere of Earth. The field of astronomy features an extensive vocabulary and a ...

  5. List of common astronomy symbols - Wikipedia

    en.wikipedia.org/wiki/List_of_common_astronomy...

    Orbital Parameters of a Cosmic Object: . α - RA, right ascension, if the Greek letter does not appear, á letter will appear. δ - Dec, declination, if the Greek letter does not appear, ä letter will appear.

  6. CfA Redshift Survey - Wikipedia

    en.wikipedia.org/wiki/CfA_Redshift_Survey

    The Center for Astrophysics (CfA) Redshift Survey was the first attempt to map the large-scale structure of the universe.. The first survey began in 1977 with the objective of calculating the velocities of the brighter galaxies in the nearby universe by measuring their redshifts at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts.

  7. Gravitational redshift - Wikipedia

    en.wikipedia.org/wiki/Gravitational_redshift

    In astronomy, the magnitude of a gravitational redshift is often expressed as the velocity that would create an equivalent shift through the relativistic Doppler effect. In such units, the 2 ppm sunlight redshift corresponds to a 633 m/s receding velocity, roughly of the same magnitude as convective motions in the Sun, thus complicating the ...

  8. Lyman-break galaxy - Wikipedia

    en.wikipedia.org/wiki/Lyman-break_galaxy

    In order to confirm the redshift estimated by the color selection, follow-up spectroscopy is performed. Although spectroscopic measurements are necessary to obtain a high-precision redshift, spectroscopy is typically much more time-consuming than imaging, so the selection of candidate galaxies via the Lyman-break technique greatly improves the ...

  9. Cosmic distance ladder - Wikipedia

    en.wikipedia.org/wiki/Cosmic_distance_ladder

    In such cases, the redshift of the host galaxy allows a determination of the Hubble constant. [22] This was the case for GW170817 , which was used to make the first such measurement. [ 25 ] Even if no electromagnetic counterpart can be identified for an ensemble of signals, it is possible to use a statistical method to infer the value of H 0 ...