Hypervariable galactic nuclei

October 31, 2016, Harvard-Smithsonian Center for Astrophysics
A photo of the PanSTARRS (Panoramic Survey Telescope & Rapid Response System) telescope in Hawaii. Astronomers have used a sky survey from this facility to identify a class of blue, hypervariable galaxies; the origin of the variability is uncertain but might in some cases be due to microlensing. Credit: PanSTARRS

Extreme variability in the intensity of the optical light of galaxies, by factors of two or more, is of great interest to astronomers. It can flag the presence of rare types of supernovae, for example, or spot sudden accretion activity around quiescent black holes or around the supermassive black hole at the galaxy's nucleus. In recent years systematic searches for such variability have been made using instruments that can survey wide swaths of the sky. One, the Panoramic Survey Telescope & Rapid Response System (PanSTARRS), is a facility capable very wide-field imaging using a combination of relatively small mirrors coupled with very large digital cameras, and it can observe the entire sky accessible to it several times a month.

CfA astronomer Martin Elvis was part of a team of scientists that looked for variability in galaxies by comparing PanSTARRS images of the sky with images taken by an earlier survey, the Sloan Digital Sky Survey, about ten years before; the results were followed up with several other telescopes. Their comparison spanned nearly one-third of the whole sky. After sifting through thousands of apparent transients per month to check, among other things, for accurate spatial coincidences, that the candidates were galaxies, and that multiple observations confirmed the variability, the team reports finding seventy-six reliable objects. Spectroscopic followups and other observations were then able to classify these into nine categories, including and radio-emitting galaxies. In the end, the team found fifteen hypervariable sources that have brightened by almost a factor of ten in the past decade; light from the most distant one of these has been traveling for about nine billion years. The galaxies' light is blue in color and has been steadily changing, usually getting weaker.

The offer four possible explanations for these strange objects. The first is microlensing: the variability is due to gravitational lensing effects by a star in a foreground galaxy. Since it seems likely that this must happen sometime, this option is slightly preferred by the authors. Variable accretion onto a black hole is another possibility, but there are no convincing physical models to describe the detailed results yet. Two other options, the tidal disruption of a passing star by a dormant black hole or variable extinction by a clumpy medium in the galaxy, seem less likely. The scientists suggest some new observations that could help sort out these different possibilities, not the least of which is a larger systematic monitoring program to increase the statistics of these strange, blue, hypervariable .

Explore further: X-ray point source discovered at the center of a distant dwarf galaxy Henize 2-10

More information: A. Lawrence et al. Slow-blue nuclear hypervariables in PanSTARRS-1, Monthly Notices of the Royal Astronomical Society (2016). DOI: 10.1093/mnras/stw1963

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6 comments

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Tuxford
1.7 / 5 (6) Nov 04, 2016
The astronomers offer four possible explanations for these strange objects.

And a fifth explanation is that proposed by LaViolette several decades ago, that the core itself if variable, occasionally erupting to eject new matter generated therein, thereby seeding the growing galaxy from the core itself, creating Fermi Bubbles, and ejecting a superwave of cosmic radiation that can alter climate, create ice ages, and illuminate the Crab Nebula as it is now. No wonder Indians and other early inhabitants of this planet sought refuge in small cities buried underground such as in the one Turkey.
Captain Stumpy
3 / 5 (2) Nov 06, 2016
No wonder Indians and other early inhabitants of this planet sought refuge in small cities buried underground
@tuxford
1- define "indians"
were you referring to the common colloquial term for the indigenous aboriginal tribes of north america? or the current populations of India?

because
2- not all "indians" lived underground

jsdarkdestruction
4.2 / 5 (5) Nov 07, 2016
If anyne wans to know where sub quantum kinetics tuxford brings up comes from here is an interesting tidbit..
". In Decoding the Message of the Pulsars, LaViolette shows that pulsars are distributed in the sky in a nonrandom fashion, often marking key galactic locations, and that their signals are of intelligent origin. Using extensive scientific data to corroborate his theory, he presents evidence of unusual geometric alignments among pulsars and intriguing pulse-period relationships. Equally compelling is the message LaViolette contends is being sent by these extraterrestrial beacons: a warning about a past galactic core explosion disaster that could recur in the near future. PAUL A. LaVIOLETTE, Ph.D., is president of the Starburst foundation."
That's right. An alien code in the pulsars which only he could decode. He also says the aliens transported him to another dimension or a dream world in the subconscious so they could award him a medal or award for figuring it out.
Tuxford
2 / 5 (4) Nov 07, 2016
If anyne wans to know where sub quantum kinetics ...

Fascinating. Dark shows up again after years hiding in the corner. Dark, are you DoD counter-intelligence, or just not intelligent? The spooks want to confuse the issue in order to divert attention away from a physics that permits electro-gravitic weaponry to be developed. This technology is far more concerning than nuclear weapons, since it is far easier for rouge nations to develop!

So they plant UFO nonsense stories, and other fanciful nonsense such as this story. Yes, LaViolette has some other ideas that may or may not be true in the end. However, he also has explained the electro-gravitic propulsion of the B2, which got him harassed by the Feds during online interviews, where they repeatedly disconnected the phone line a dozen times in two hours.

So, I limit my discussion to cosmology.
Captain Stumpy
3 / 5 (2) Nov 07, 2016
@tuxford
he also has explained the electro-gravitic propulsion of the B2
this is called pure unadulterated balderdash, AKA- pseudoscience

the B2 uses
four General Electric F118-GE-100 engines
http://www.af.mil...rit.aspx

So, I limit my discussion to cosmology.
you mean your version of cosmology, which isn't always based in reality, hence your comment
No wonder Indians and other early inhabitants of this planet sought refuge in small cities buried underground
you do know that a serious minority of Natives actually lived underground, sheltered by the ground or using ground/earth shelters above ground level, right?

it's not like that hasn't ever been studied

it's just a matter of actually looking it up - you know, like the above B2 statistics
(also published in Janes or Pace & available to the public)
Benni
3 / 5 (4) Nov 07, 2016
Be careful, your post may be suppressed for criticizing these lunatics.
PO has a soft spot for cranks.
......that's for sure.........you're still allowed to be here in spite of all the foul mouth filth you continue to crank out.

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