Astronomers using the NASA/ESA Hubble Space Telescope have captured a stunning new image of part of a spiral galaxy called NGC 45.
This Hubble image shows of the outer arms of NGC 45, a spiral galaxy some 22 million light-years away in the constellation of Cetus. The color image was made from separate exposures taken in the ultraviolet, visible and near-infrared regions of the spectrum with Hubble’s Wide Field Camera 3 (WFC3) instrument. It is based on data obtained through seven filters. The color results from assigning different hues to each monochromatic image associated with an individual filter. Image credit: NASA / ESA / Hubble / D. Calzetti / R. Chandar / M.H. Özsaraç.
NGC 45 is located approximately 22 million light-years away in the constellation of Cetus.
Also known as DDO 223, ESO 473-1 or LEDA 930, this galaxy is around 81,000 light-years across.
NGC 45 was discovered by the English astronomer John Herschel on November 11, 1835.
“The Hubble data used to create this portrait of NGC 45 were drawn from two complementary observing programs,” Hubble astronomers said in a statement.
“The first took a broad view of 50 nearby galaxies, leveraging Hubble’s ability to observe light from the ultraviolet to the near-infrared in order to study star formation in these galaxies.”
“The second program examined many of the same nearby galaxies as the first, narrowing in on a particular wavelength of red light called H-alpha.”
“Star-forming nebulae are powerful producers of H-alpha light, and several of these regions can be identified across NGC 45 by their bright pink-red color.”
“These observing programs aimed to study star formation in galaxies of different sizes, structures, and degrees of isolation — and NGC 45 makes for a particularly interesting target.”
Though it may appear to be a regular spiral galaxy, NGC 45 is actually a remarkable type called a low surface brightness galaxy.
“Low surface brightness galaxies are fainter than the night sky itself, making them incredibly difficult to detect,” the researchers said.
“They appear unexpectedly faint because they have relatively few stars for the amount of gas and dark matter they carry.”
“In the decades since the first low surface brightness galaxy was serendipitously discovered in 1986, researchers have learned that 30-60% of all galaxies may fall into this category.”
“Studying these hard-to-detect galaxies is key to understanding how galaxies form and evolve, and Hubble’s sensitive instruments are equal to the task.”
