Finding well-hidden galaxies

Well-hidden galaxies can be discovered through the imprint their interstellar gas leave on the spectrum of an even more remote quasar. Interstellar clouds of gas in galaxies, located between the quasars and us on the same line of sight, absorb parts of the light emitted by the quasars. The resulting spectrum consequently presents dark ''valleys'' that can be attributed to well-known elements and possibly molecules. In this schematic representation, the VLT observes (D) the features associated with three systems, located at different distances (A, B, and C), and whose light is therefore shifted by different amounts. The quasar, which acts as a beacon, is the bright object at the left of the image.

Credit:

ESO

About the Image

Id:eso0813a
Type:Artwork
Release date:13 May 2008
Related releases:eso0813
Size:914 x 691 px

About the Object

Name:Spectrum
Type:Unspecified : Galaxy
Unspecified : Nebula : Type : Interstellar Medium
Category:Galaxies
Illustrations
Nebulae

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