Observatory in Hawaii captures collision between galaxies NGC 5394 and NGC 5395 in unprecedented detail

Telescópio Gemini Norte, installed at the top of the inactive volcano Maunakea, in Havaí, obtained a detailed record of the gravitational interaction between the spiral galaxies NGC 5394 and NGC 5395. The cosmic phenomenon occurs in the constellation of Cães and Caça, located at an approximate distance of 160 million light years from the planet Terra. The photographic capture highlights the severe structural distortions caused by the physical proximity between the two massive objects. Astronomical equipment highlighted vast regions of intense star formation that arise as a direct consequence of gravitational friction.

The dynamics between the two celestial bodies permanently alter the distribution of cosmic gas and dust within their interiors. The force of mutual attraction attracts clouds of hydrogen to specific areas, which triggers the collapse of material and creates nurseries of new stars. Visual recording allows scientists to understand the physical mechanisms that regulate the growth and evolution of galaxies over the eons of the universe. Continuous observation of this system provides essential data about the stellar life cycle.

NGC 5395 (left) is a striking spiral galaxy 160 million light-years away in Canes Venatici. Its warped form and off-center ring are caused by a dramatic encounter with its smaller neighbour, NGC 5394.

(Credit: International Gemini Observatory/NOIRLab/NSF/AURA) pic.twitter.com/Un8awDFg6U

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Dinâmica collision and formation of new stars in deep space

The continued approach between NGC 5394 and NGC 5395 modifies the internal movement of galactic material and distorts the original spiral arms of both. Essa Mechanical turbulence generates ideal conditions for the emergence of young, extremely hot stars. The hydrogen gas ionized by this newly created radiation emits a strong reddish light, which appears in the captured image as small, ring-shaped bright spots. Essas specific areas are classified by astronomers as HII regions.

The process of galactic fusion not only acts to destroy old structures, but works as an engine of cosmic renewal. The accelerated birth of stars, known in scientific circles as starburst, enriches the space environment with heavy chemical elements forged in the stellar cores. The visible bridges of material between the two galaxies demonstrate physical mass transfer. The interaction event has already happened at least once in the past, as indicated by analyzes of the tidal tails left by the movement.

Movimentos gravitational forces of this magnitude require millions of years for full fusion. Observing this stage offers a unique temporal window into astrophysics. The study of velocities calibrates the computational models that simulate the evolution of the cosmos.

Individual Características of the pair known as Galáxia of Garça

British astronomer William Herschel made the first official identification of NGC 5394 and NGC 5395 in the year 1787. Quase two centuries later, in 1966, researcher Halton Arp cataloged the system under the designation Arp 84 in his Atlas of Galáxias Peculiares. The set was nicknamed Galáxia from Garça due to its visual silhouette in deep space. The larger galaxy represents the bird’s body, while the smaller, more elongated structure simulates the head and beak.

A third galaxy, much more distant and without a direct gravitational relationship with the main event, appears in the image near the tip of the heron’s beak. The main system, however, attracts attention due to the distinct properties of each component. Spectroscopic analysis reveals fundamental differences in the composition and behavior of the two objects on a collision course.

• NGC 5395 has a diameter of 140 thousand light years and is classified as an active galaxy of the Seyfert II type.
• The center of the larger galaxy hosts a likely supermassive black hole that influences the dynamics of its core.
• NGC 5394, which acts as the smaller companion, has a compact structure with a very high rate of star formation.

Galaxies of the Seyfert II type, such as NGC 5395, are characterized by having active nuclei that emit intense radiation, often obscured by dense dust clouds. The interaction with the smaller companion enhances this central activity by providing a constant flow of fresh material to the black hole. The slow and mutual rotation of the two bodies keeps the system in a fragile and dynamic equilibrium.

Recent Supernova and the galactic winds detected by researchers

The drastic increase in the stellar birth rate brings as a direct consequence an increase in the number of deaths of massive stars. In 2020, monitoring equipment detected the explosion of the supernova SN 2020aaxs inside the galaxy NGC 5394. Esse cataclysmic event of the Ib type marked the final gravitational collapse of a giant star that was formed precisely during the process of interaction between galaxies. The explosion serves as an irrefutable temporal marker of recent activity in the system.

The energy released by these explosions and by the radiation from young stars generates multiphase galactic winds of extreme power. Esse phenomenon drives neutral gas and ionized gas out of the center of the galaxy at high speed. Astronomical data indicate that a significant portion of this material manages to escape local gravitational pull. The ejected gas travels through space and ends up enriching the vast intergalactic environment with new elements.

The detection of supernovae in interacting systems reinforces that collisions catalyze the chemical evolution of the universe. The material spread by SN 2020aaxs will serve as raw material for future planetary systems. Observing these winds requires instruments capable of separating the light signatures of the gas.

Tecnologia from the observatory and the importance of recording for science

Capturing the image required the use of the Gemini Multi-Object Spectrograph, an advanced instrument operated in imaging mode on the eight-meter diameter telescope. The technical team carried out a total exposure of 42 minutes to record the faint light coming from the Arp 84 system. The process involved the composition of four filters of different colors, designed specifically to isolate the emissions from ionized hydrogen and the brightness of newborn stars.

The Telescópio Gemini Norte’s main mirror provides the optical resolution needed to distinguish fine details at extreme cosmological distances. The infrastructure installed at Havaí benefits from the region’s high altitude and stable atmosphere, factors that reduce visual distortion caused by terrestrial air. The combination of cutting-edge hardware and ideal geographic conditions allows scientists to map gas flows with unprecedented clarity.

Monitoring of NGC 5394 and NGC 5395 will continue to record structural changes. Additional spectroscopy will provide accurate measurements on the chemical composition and velocity of the dust clouds. The dataset consolidates understanding of the forces that transform the structures of the cosmos.