NGC 1569, a dynamic galaxy

 

 

 

 

 

 

 

 

NGC 1569 is a dwarf irregular galaxy located in the constellation Camelopardalis, at a distance of roughly 10 to 11 million light-years from Earth. Despite its small size, it is one of the most active nearby starburst galaxies, having undergone intense episodes of star formation over the past few hundred million years. This activity has produced an unusually high number of young massive clusters, including super star clusters (SSCs) that resemble the progenitors of globular clusters. Its starburst has also driven strong galactic winds, observable in Hα and X-ray emission, which have expelled gas into the intergalactic medium.

NGC 1569 is not an isolated system. It belongs to the IC 342/Maffei galaxy group, a collection of galaxies lying near the Galactic plane. Within this group, NGC 1569 is closely associated with UGCA 92 and UGCA 86, two nearby dwarf irregular galaxies that are South and outside the field of this image (North is to the lower right). Their proximity in position and radial velocity strongly suggests gravitational interactions.

UGCA 92, located about 1° away from NGC 1569 on the sky, lies at a similar distance. It exhibits properties typical of a gas-rich dwarf irregular galaxy, with modest star formation but a large reservoir of neutral hydrogen (H I). UGCA 86, somewhat farther in projection, shows comparable characteristics, with extended H I structures that may indicate tidal interactions. The presence of these neighbors supports the hypothesis that the recent burst of star formation in NGC 1569 was triggered by gravitational encounters. Such interactions are known to compress gas, fueling bursts of star formation in dwarfs.

Multi-wavelength observations reinforce this scenario. Deep H I mapping reveals bridges of neutral gas possibly linking NGC 1569 with UGCA 92. Additionally, stellar population studies using the Hubble Space Telescope show that the most recent starburst in NGC 1569 began about 100 Myr ago, which is consistent with the timescale of an encounter with it.

Actually, the HII clouds have such a strong signal that the galaxy is pretty much hidden behind this glare. Therefore, by partially obscuring this signal in the area where the galaxy is, it is possible to have a complete sight of what aspect this galaxy really has (see below).