A new report from ESO (European Southern Observatory):
Dazzling Spiral with an Active Heart
This picturesque spiral galaxy appears to be tranquil, but there is more to it than meets the eye. Messier 77 (also known as NGC 1068) is one of the closest active galaxies, which are some of the most energetic and spectacular objects in the Universe. Their nuclei are often bright enough to outshine the whole of the rest of the galaxy. Active galaxies are among the brightest objects in the Universe and emit light at most, if not all, wavelengths, from gamma rays and X-rays all the way to microwaves and radiowaves. Messier 77 is further classified as a Type II Seyfert galaxy, characterised by being particularly bright at infrared wavelengths.
ESO’s Very Large Telescope (VLT) has captured a magnificent face-on view of the barred spiral galaxy Messier 77. But there is more to this galaxy than meets the eye. This ESOcast Light takes a closer look.
This impressive luminosity is caused by intense radiation blasting out from a central engine — the accretion disc surrounding a supermassive black hole. Material that falls towards the black hole is compressed and heated up to incredible temperatures, causing it to radiate a tremendous amount of energy. This accretion disc is thought to be enshrouded by thick doughnut-shaped structure of gas and dust, called a “torus”. Observations of Messier 77 back in 2003 were the first to resolve such a structure using the powerful VLT Interferometer (eso0319).
This video sequence takes the viewer deep into a detailed view of the active galaxy Messier 77 from ESO’s Very Large Telescope in northern Chile. Credit: ESO/Digitized Sky Survey 2
This image of Messier 77 was taken in four different wavelength bands represented by blue, red, violet and pink (hydrogen-alpha) colours. Each wavelength brings out a different quality: for example, the pinkish hydrogen-alpha highlights the hotter and younger stars forming in the spiral arms, while in red are the fine, thread-like filamentary structures in the gas surrounding Messier 77 [1]. A foreground Milky Way star is also seen beside the galaxy centre, displaying tell-tale diffraction spikes. Additionally, many more distant galaxies are visible; sitting at the outskirts of the spiral arms, they appear tiny and delicate compared to the colossal active galaxy.
This image was obtained using the FOcal Reducer and low dispersion Spectrograph 2 (FORS2) instrument mounted on Unit Telescope 1 (Antu) of the VLT, located at ESO’s Paranal Observatory in Chile. It hails from ESO’s Cosmic Gems programme, an outreach initiative that produces images of interesting, intriguing or visually attractive objects using ESO telescopes for the purposes of education and outreach.
This video pan shows a new image from ESO’s Very Large Telescope of Messier 77. Also known as NGC 1068, Messier 77 is one of the closest active galaxies, which are some of the most energetic and spectacular objects in the Universe. Credit: ESO
Notes
[1] Similar red filaments are also found in NGC 1275. They are cool, despite being surrounded by a very hot gas at around 50 million degrees Celsius. The filaments are suspended in a magnetic field which maintains their structure and demonstrates how energy from the central black hole is transferred to the surrounding gas.
[2] NGC 1055 is located about 60 million light-years away. It is an edge-on galaxy, in contrast to Messier 77. This Astronomy Picture of the Day portrays both of them together, in a field of view about the size of the Moon (APOD).
