15 July 2022

Galaxy clusters and gravitational lensing


The furthest-from-earth non-supernova star was discovered incidentally because its light emissions were lensed around a cluster of galaxies.
MACS J1149+2223 Lensed Star-1, also known as Icarus, is a blue supergiant observed through a gravitational lens and the most distant individual star detected, at 9 billion light-years from Earth... Light from the star was emitted 4.4 billion years after the Big Bang.  According to co-discoverer Patrick Kelly, the star is at least a hundred times more distant than the next-farthest non-supernova star observed, and is the first magnified individual star seen.
More at the link.  I find it curiously difficult to think about this star using verbs in the present tense, since everything we know about it (position, size, wavelengths) describe it nine billion years ago.

Related (with some discussion of gravitational lensing): The first "multiple-image gravitationally-lensed supernova."

Also related: List of star extremes (nearest, oldest, brightest, hottest, least massive, fastest moving...)

Reposted from 2018 to add this instructional video about gravitational lensing, presented by Patrick Kelly.  The lecture was presented at the Minnesota Institute for Astrophysics last year.


Patrick is scheduled to do some projects involving the JWST, presumably to image via lensing some stars even closer to the Big Bang than the current limits of the standard microwave images.

3 comments:

  1. More stars in the universe than grains of sand on earth (with who knows how many planets around each)- and yet many (most?) scientists scoff at the idea of an ET more advanced than us, one ancient and advanced enough to have mastered the physics of visiting us.

    It's amazing that they can obligingly accept a theory, yet refuse to even consider the actual possibility of its consequences...

    https://www.npr.org/sections/krulwich/2012/09/17/161096233/which-is-greater-the-number-of-sand-grains-on-earth-or-stars-in-the-sky

    https://www.airspacemag.com/daily-planet/odds-were-only-technologically-advanced-species-universe-are-extremely-low-180958975/

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  2. I do wish NASA could get rid of the diffraction spikes. Surely there must be some image processing software that can do that?

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  3. Perhaps by not even acknowledging the possibility of other "civilizations" they are trying to tamp down wild speculation of the Star Trek, Star Wars kind which distract from real science. I suspect that even the slightest indication of something would be jumped on.

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