The Hubble Space Telescope photograph of NGC 1559 shows the active star formation regions of the galaxy using special light filters
NGC 1559, a distant spiral bar galaxy, captured in a composite image by the Hubble Space Telescope
The impressive galaxy featured in Hubble's stunning image of the week is NGC 1559. It is a spiral bar galaxy in a grid group near the Large Magellanic Cloud, but much further away, about 35 light-years from Earth. Hubble last visited this bone in 2018. The bright light captured in this image provides a wealth of information, which thanks to Hubble can be used by scientists and the public.
This image is made up of less than ten separate images taken by the Hubble Space Telescope, each filtered to collect light of a specific wavelength or range of wavelengths. All of Hubble's light sensitivity is included, from UV at a wavelength of around 275 nm through blue, green and red to near AA at a wavelength of 1600 nm.
This makes it possible to record information about many different astrophysical processes in the galaxy: a notable example is the red 656 nm filter used here. Hydrogen atoms that ionize can emit light at this specific wavelength, called H-alpha emission.
New stars forming in a molecular cloud, made mostly of hydrogen gas, emit copious amounts of UV light that is absorbed by the cloud, but ionizes it and causes it to glow with this H-alpha light. Therefore, filtering to detect only this light is a reliable means of detecting regions of star formation (called H II regions), shown in this image in the bright red and pink colors of the confusing blobs that fill the spiral arms of NGC 1559.
These ten images originate from six different Hubble viewing programs, from 2009 to this year. These programs were run by teams of astronomers from around the world with a variety of scientific goals, such as studying ionized gas and star formation, tracking supernovae, and tracking variable stars as a contribution to the calculation of the Abel constant.
