I am currently processing a backlog of old images. This one, the "classical" M51 interacting couple, was taken on the night of 28.2 2022. Probably my intention was to add more signal, that never happened. In any case the data is sufficient to show some of the matter waves ejected by the two interacting galaxies.
Similar interactions are not rare in the universe: I have photographed a similar one, Arp 239,  a few months ago. It is 10 times more distant than M51.

The Whirlpool Galaxy
Also known as Messier 51a, and NGC 5194, it is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus, in the constellation Canes Venatici, 31 million light-years away from Earth. The Whirlpool Galaxy has an estimated diameter of 76,000 light-years, about 43% the size of the Milky Way. Its mass is estimated to be around 10% of the mass of Milky Way Galaxy.
It was the first galaxy to be recognized to have a spiral shape by Lord Rosse (see picture below).

It was discovered on October 13, 1773, by Charles Messier, and was designated in Messier's catalogue as M51. Its companion galaxy, NGC 5195, was discovered in 1781 by Pierre Méchain, although it was not known whether it was interacting or merely another galaxy passing at a distance.
In 1845, William Parsons, 3rd Earl of Rosse, employing a 72-inch (1.8 m) reflecting telescope at Birr Castle, Ireland, found that the Whirlpool possessed a spiral structure, the first "nebula" to be known to have one. These "spiral nebulae" were not recognized as galaxies until Edwin Hubble was able to observe Cepheid variables in some of these spiral nebulae, which provided evidence that they were so far away that they must be entirely separate galaxies.
The advent of radio astronomy and subsequent radio images of M51 demonstrated that the Whirlpool and its companion galaxy are indeed interacting. Sometimes the designation M51 is used to refer both galaxies together, in which case the individual galaxies may be referred to as M51a (NGC 5194) and M51b (NGC 5195).


Sketch of M51 by Lord Rosse in 1845 (Unknown source - Wikipedia)

A black hole, once thought to be surrounded by a ring of dust, but now believed to be partially occluded by dust instead, exists at the heart of the spiral. A pair of ionization cones extend from the active galactic nucleus.

The pronounced spiral structure of the Whirlpool Galaxy is believed to be the result of the close interaction between it and its companion galaxy NGC 5195, which may have passed through the main disk of M51 about 500 to 600 million years ago. In this proposed scenario, NGC 5195 came from behind M51 through the disk towards the observer and made another disk crossing as recently as 50 to 100 million years ago until it is where we observe it to be now, slightly behind M51.

The central region of M51 appears to be undergoing a period of enhanced star formation. The present efficiency of star formation, defined as the ratio of mass of new stars to the mass of star-forming gas, is only ~1%, quite comparable to the global value for the Milky Way and other galaxies. It is estimated that the current high rate of star formation can last no more than another 100 million years or so.

Extra-galactic Exoplanet
In September 2020, the detection by the Chandra X-ray Observatory of a candidate exoplanet, named M51-ULS-1b, orbiting the high-mass X-ray binary M51-ULS-1 in this galaxy was announced. If confirmed, it would be the first known instance of an extra-galactic planet, a planet outside the Milky Way Galaxy. The planet candidate was detected by eclipses of the X-ray source (XRS), which consists of a stellar remnant (either a neutron star or a black hole) and a massive star, likely a B-type super-giant. The planet would be slightly smaller than Saturn and orbit at a distance of some tens of astronomical units.

(Excerpted from Wikipedia)