This image from the NASA/ESA Hubble Space Telescope features two stunning galaxies — the compact elliptical galaxy NGC 1510 and its colossal neighbor, the barred spiral galaxy NGC 1512 — engaged in an intergalactic dance.
This composite image shows the barred spiral galaxy NGC 1512 (left) and the elliptical galaxy NGC 1510 (right). Image credit: NASA / ESA / Hubble.
NGC 1512 resides in the southern constellation of Horologium and is roughly 39 million light-years away from Earth.
Also known as ESO 250-4, LEDA 14391 and IRAS 04022-4329, the galaxy spans 70,000 light years, nearly as much as our own Milky Way Galaxy.
It is classified as a barred spiral galaxy, named after the bar composed of stars, gas and dust slicing through its center.
The bar acts as a cosmic funnel, channeling the raw materials required for star formation from the outer ring into the heart of the galaxy.
This pipeline of gas and dust in NGC 1512 fuels intense star birth in the bright, blue, shimmering inner disc known as a circumnuclear starburst ring, which spans 2,400 light-years.
Both the bar and the starburst ring are thought to be at least in part the result of the cosmic scuffle between the two galaxies — a merger that has been going on for 400 million years.
NGC 1512 is also home to a second, more serene, star-forming region in its outer ring.
This ring is dotted with dozens of HII regions, where large swathes of hydrogen gas are subject to intense radiation from nearby, newly formed stars. This radiation causes the gas to glow and creates the bright knots of light seen throughout the ring.
Remarkably, NGC 1512 extends even further than we can see in this image — beyond the outer ring — displaying malformed, tendril-like spiral arms enveloping the elliptical galaxy NGC 1510 (also known as ESO 250-3, LEDA 14375 and IRAS F04018-4332).
These huge arms are thought to be warped by strong gravitational interactions with NGC 1510 and the accretion of material from it.
But these interactions are not just affecting NGC 1512; they have also taken their toll on the smaller of the pair.
The constant tidal tugging from its neighbor has swirled up the gas and dust in NGC 1510 and kick-started star formation that is even more intense than in NGC 1512.
This causes the galaxy to glow with the blue hue that is indicative of hot new stars.
NGC 1510 is not the only galaxy to have experienced the massive gravitational tidal forces of NGC 1512.
Observations made in 2015 showed that the outer regions of the spiral arms of NGC 1512 were indeed once part of a separate, older galaxy. This galaxy was ripped apart and absorbed by NGC 1512, just as it is doing now to NGC 1510.
