For You Lot Data - Gravitationally Lensed Quasars

The path of calorie-free is bent yesteryear mass, an number predicted yesteryear Einstein's theory of gravity, as well as when a massive galaxy or cluster lies along our line-of-sight to a to a greater extent than distant galaxy its affair volition human activity every bit a lens to icon the calorie-free from that object. So-called potent gravitational lensing creates highly distorted, magnified as well as oft multiple images of a unmarried source. (Strong lensing is distinct from weak lensing which results inward modestly deformed shapes of background galaxies.)

(left) Influenza A virus subtype H5N1 near-infrared icon of a quasar whose calorie-free has been traveling for most 10 billion years as well as which has been
distorted yesteryear an intervening galaxy into a reimaged (gravitationally lensed) laid upwards of 4 images of the same quasar.
The correct frame shows the faint intervening galaxy afterwards subtraction of the 4 quasar images
[Credit: Anguita et al. 2018]

Quasars are galaxies amongst massive dark holes at their cores to a greater extent than or less which vast amounts of unloose energy are beingness radiated, to a greater extent than than from the residue of the entire host galaxy. Their luminosities permit quasars to last seen at cosmological distances as well as they are thus probable candidates for potent lensing, amongst a few hundred gravitationally lensed quasars known so far. They convey provided valuable information non alone most quasars as well as lensing simply also on cosmology since the distorted calorie-free paths of the distant objects convey traveled across cosmological distances.

CfA astronomer David James was a fellow member of a large international squad systematically searching for novel gravitationally lensed quasars. They used the WISE infrared all-sky survey to search for candidates whose infrared colors suggested they were galaxies amongst active nuclei (like quasars). They processed images of these candidates amongst a sophisticated algorithm looking for show of their beingness multiple components, such every bit would last expected from a lensed system, as well as so followed upwards this subset amongst spectroscopic as well as ground-based imaging observations using higher spatial resolution than WISE.

Of the master copy laid upwards of fifty-four candidates, they constitute ii whose spectra confirmed that they were gravitationally lensed quasars, 1 amongst 4 sub-images as well as 1 amongst two, each of whose calorie-free has been traveling towards us for most 10 billion years. The images inward these ii cases also showed traces of the lensing galaxy, an of import verification of the lensing effect, although the galaxies were every bit good faint to obtain measurements of their distances. The scientists also identified some other 7 objects that are probable to last doubled-quasars, simply farther interrogation is needed to confirm those results.

The report is published inward Monthly Notices of the Royal Astronomical Society.

Source: Harvard-Smithsonian Center for Astrophysics [November 17, 2018]


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