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Cosmology Creation/evolution Physics

Changing-look quasars

— how do they fit into a biblical creationist model?

The quasar 3C 273, which resides in a giant elliptical galaxy in the constellation of Virgo.
Figure 1a: The quasar 3C 273, which resides in a giant elliptical galaxy in the constellation of Virgo. Credit: ESA/Hubble & NASA

Quasars are very high redshift astronomical objects with broad emission line (BEL) spectra. The latter is very different to that in the usual humdrum galaxies. This means the objects redshifts and BEL spectra can be used to identify them. And because of their high redshifts they are assumed to be very distant, very luminous active galaxies with super-massive black holes at their hearts, powering them to emit prodigious amounts of radiation over all wave-bands of the electromagnetic spectrum.

Figure 1b: Spectra of quasar 3C 273 compared to the star Vega. Spectral lines are shifted towards the red end of the spectrum, from which its distance is determined using the standard CDM cosmology.
Figure 1b: Spectra of quasar 3C 273 compared to the star Vega. Spectral lines are shifted towards the red end of the spectrum, from which its distance is determined using the standard LCDM cosmology.

Most of the high redshift objects in the universe are quasars. The redshifts of galaxies and quasars when interpreted within big bang cosmology—the greater the redshift the greater the distance—means that the most distant objects are seen at a time when the Universe was youngest.1

Following big bang thinking, quasars are then considered to be just galaxies in some early stage of development—back closer in time to the big bang—than the usual spiral and elliptical galaxies we might see with much lower redshifts. The quasar 3C 273, shown in Fig. 1a, the first to be identified (discovered in the early 1960s by astronomer Allan Sandage), has been shown to reside in a giant elliptical galaxy in the constellation of Virgo. According to standard cosmology its redshift puts it at a distance of 2.5 billion light-years from Earth.

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astronomy Cosmology Creation/evolution

Four high redshift quasars puzzle astronomers

A team of astronomers led by Joseph Hennawi of the Max Planck Institute for Astronomy, using the W.M.  Keck observatory in Hawaii, have discovered the first quadruple quasar: four quasars with approximately the same redshift of about z ~ 2 and located on the sky in close proximity.  The online article1 from Max Planck Institute is titled “Quasar quartet puzzles scientists” with the subtitle “Astronomers must rethink models about the development of large-scale cosmic structures.” This is a discovery of the first known group of four quasars with the same redshift found in the same location on the sky. A research paper has been accepted for publication in the journal Science and a preprint is now available.2

The quartet resides in one of the most massive structures ever discovered in the distant universe, and is surrounded by a giant nebula of cool dense gas. Either the discovery is a one-in-ten-million coincidence, or cosmologists need to rethink their models of quasar evolution and the formation of the most massive cosmic structures.1

4 quasars zoom
Caption from original article: Rare find: This image depicts the region in space with the quadruple quasars. The four quasars are indicated by arrows. The quasars are embedded in a giant nebula of cool dense gas visible in the image as a blue haze. The nebula has an extent of one million light-years across, and these objects are so distant that their light has taken nearly 10 billion years to reach telescopes on Earth. This false color image is based on observations with the 10-m-Keck-telescope on the summit of Mauna Kea in Hawaii. Credit: Arrigoni-Battaia & Hennawi / MPIA  (Ref. 1)