Big Dipper Ripple

Scientists have known for a long time that the central regions of galaxies not only glow brightly, but also change the brightness of the glow from time to time. The reasons for this are not yet clear, astronomers argue and are looking for a clue.

Explanations proposed so far include changes in the attenuation of light as it travels through dust, changes in the brightness of the accretion disk or associated regions, supernova explosions in the nuclear regions of galaxies, and even gravitational lensing.

To eliminate these uncertainties, additional studies of the variability of galactic centers are needed. One such study was carried out by a group of astronomers led by Daniel Kinoch of the University of Durham, USA, using various ground-based telescopes. The researchers conducted an optical photometric and spectroscopic study of the galaxy SDSS J2232-0806, also known as the Big Dipper.

The galaxy is 4.5 billion light years away, has a redshift of 0.276 and a variable luminosity core.

Astronomers have analyzed 11 optical spectra of the galaxy so far, and are continuing to collect data in other bands - infrared, ultraviolet and X-rays.

It turned out that SDSS J2232-0806 probably flares up periodically. The galaxy was bright when it was first seen in the late 1980s, very dim in 2000, and another dip occurred between 2005 and 2007. The pulsation period is supposed to be about four years.

This, apparently, means that the observed brightness is not influenced by any factors that occur on the path of light to us. Taking into account the distance to the galaxy, there could be many such factors, but their influence is not traced.

From this it follows that the change in the luminosity of the galaxy is due to some internal reasons. What exactly - someday scientists will tell about this.

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