250331 - M64 "Black Eye" galaxy
|
click image to enlarge
|
ASTRO:
type=Spiral galaxy const=Coma Bernices mag=8.5 dist=17 M ly size=53k ly IMAGE: location=EB Driveway BrtlCls=4 moon=29% WnCr exposure=CMOS OSC: 144x180s (7.2h), G100 EQUIPMENT: camera=ZWO ASI2600MC-Pro optics=ES102 w24mmEP 1.7x (afoc prjctn), F=1238mm, f/12.1 filter=Optolong L-Pro LPS mount=Celestron AVX guiding=Orion 60x240mm, ZWO ASi224MC SOFTWARE: acquisition=Stellarium, NINA, PHD2 processing=PixInsight (RCAstro), Photoshop (RCAstro) (APF-R), LrC |
|
The Black Eye Galaxy, also sometimes called the Sleeping Beauty or Evil Eye galaxy, and designated Messier 64, (or M64), and NGC 4826, is a relatively isolated spiral galaxy. ...meaning there are no other galaxies identified as being gravitational bound into a "group" with this one. The Black Eye appears to be suspended in space appx 17 million light-years away from Earth in the otherwise well-groomed northern constellation Coma Berenices. The enormous dust clouds partially obscuring M64's inner central region - the middle ¼ of the galaxy's total diameter - are laced with the reddish glow of hydrogen associated with star forming regions. But tightly confined, dominating clouds of dust are not this galaxy's only peculiar feature. Observations show that M64 is actually composed of two (2) concentric, counter-rotating systems. While all the visible stars in M64 rotate in the same direction as the interstellar gas in the galaxy's central region, the gas present in the outer regions, extending outward another 40,000 light-years beyond the central region, rotates in the opposite direction. The dusty "eye" and bizarre rotation are likely the result of a billion-year-old merger of two (2) different galaxies.
M64 was discovered by English astronomer Edward Pigott in March 1779. Professor Pigott is noted for being one of the founders of the study of variable stars. Subsequently, M64 was also independently discovered by German astronomer Johann Elert Bode in April of the same year, as well as by Charles Messier the next year. A dark band of absorbing dust located partially in front of its bright nucleus gives rise to its nicknames.
This galaxy is inclined 60° to our line-of-sight from here on Earth, and has an apparent position angle of 112°. Calculated at the distance of this galaxy, its linear scale (diameter) of appx 53,000 ly is appx 30% of the size of our home Milky Way galaxy. M64's morphological classification in the system created by renown French galaxy specialist Gérard Henri de Vaucouleurs, is (R)SA(rs)ab, where the '(R)' indicates the presence of an outer ring-like structure, 'SA' denotes a non-barred spiral, '(rs)' means a transitional inner ring/spiral structure, and 'ab' says the spiral arms are tightly wound.
M64 is a type 2 Seyfert galaxy with a HII / LINER nucleus - meaning Low-Ionization Nuclear Emission-line Region (LINER) - a type of galactic nucleus that is defined by its spectral light emissions. These types of spectral emissions typically reveal the presence of weakly ionized Hydrogen, Oxygen, Nitrogen, and Sulphur. This class of galactic nuclei was first identified by Dr. Timothy Heckman (John's Hopkins Univ.) in the third of a series of papers on the spectra of galactic nuclei that were published in 1980. The central region is also a weak source of radio emissions. A soft X-ray source has also been detected, which is most likely coming from the region encircling just outside the nucleus rather than directly from the active galactic nucleus itself. There is an inner disk of molecular gas with a fairly abrupt transition at a radius of appx 2,300 ly. At present, the non-rotational motions of this disk do not significantly feed the core, but the disk does produce a vigorous rate of star formation. There are appx 100 billion stars inside the galaxy. There is also evidence of a recent large inflow of mass, perhaps indicative of past interaction with another galactic body. The central supermassive black hole is calculated to have a mass of appx 8.4 M solar masses.
The two counter-rotating disks are approximately equal in mass. The inner disk contains the prominent dust lanes of the central region, and also the stellar population of the galaxy exhibiting no measurable counter-rotation. Possible formation scenarios include a merger with a gas-rich satellite galaxy in a retrograde (directionally opposite) orbit, or the continued accretion (process of growth) of gas clouds acquired from the intergalactic medium outside the galaxy.
M64 is well known among amateur observers due to its distinguishable form in small telescopes, and its visible accessibility across a broad span of latitudes. Similarly, it is a favorite of imagers due to its beautiful complexity; but also, its brightness makes it a reasonably easy target to capture with moderate to long focal lengths (greater than ~600mm).
M64 was discovered by English astronomer Edward Pigott in March 1779. Professor Pigott is noted for being one of the founders of the study of variable stars. Subsequently, M64 was also independently discovered by German astronomer Johann Elert Bode in April of the same year, as well as by Charles Messier the next year. A dark band of absorbing dust located partially in front of its bright nucleus gives rise to its nicknames.
This galaxy is inclined 60° to our line-of-sight from here on Earth, and has an apparent position angle of 112°. Calculated at the distance of this galaxy, its linear scale (diameter) of appx 53,000 ly is appx 30% of the size of our home Milky Way galaxy. M64's morphological classification in the system created by renown French galaxy specialist Gérard Henri de Vaucouleurs, is (R)SA(rs)ab, where the '(R)' indicates the presence of an outer ring-like structure, 'SA' denotes a non-barred spiral, '(rs)' means a transitional inner ring/spiral structure, and 'ab' says the spiral arms are tightly wound.
M64 is a type 2 Seyfert galaxy with a HII / LINER nucleus - meaning Low-Ionization Nuclear Emission-line Region (LINER) - a type of galactic nucleus that is defined by its spectral light emissions. These types of spectral emissions typically reveal the presence of weakly ionized Hydrogen, Oxygen, Nitrogen, and Sulphur. This class of galactic nuclei was first identified by Dr. Timothy Heckman (John's Hopkins Univ.) in the third of a series of papers on the spectra of galactic nuclei that were published in 1980. The central region is also a weak source of radio emissions. A soft X-ray source has also been detected, which is most likely coming from the region encircling just outside the nucleus rather than directly from the active galactic nucleus itself. There is an inner disk of molecular gas with a fairly abrupt transition at a radius of appx 2,300 ly. At present, the non-rotational motions of this disk do not significantly feed the core, but the disk does produce a vigorous rate of star formation. There are appx 100 billion stars inside the galaxy. There is also evidence of a recent large inflow of mass, perhaps indicative of past interaction with another galactic body. The central supermassive black hole is calculated to have a mass of appx 8.4 M solar masses.
The two counter-rotating disks are approximately equal in mass. The inner disk contains the prominent dust lanes of the central region, and also the stellar population of the galaxy exhibiting no measurable counter-rotation. Possible formation scenarios include a merger with a gas-rich satellite galaxy in a retrograde (directionally opposite) orbit, or the continued accretion (process of growth) of gas clouds acquired from the intergalactic medium outside the galaxy.
M64 is well known among amateur observers due to its distinguishable form in small telescopes, and its visible accessibility across a broad span of latitudes. Similarly, it is a favorite of imagers due to its beautiful complexity; but also, its brightness makes it a reasonably easy target to capture with moderate to long focal lengths (greater than ~600mm).