Messier 59
Elliptical galaxy in Virgo with a counter-rotating supermassive black hole.
Messier 59 (M59, NGC 4621) is an elliptical galaxy located in the equatorial constellation Virgo and belongs to the Virgo Cluster. Its nearest neighbor in the cluster lies 8 arcminutes away and is about 5 magnitudes fainter; the closest cluster member of comparable brightness is the lenticular galaxy NGC 4638, roughly 17 arcminutes distant. M59 and the nearby elliptical galaxy Messier 60 were both discovered by Johann Gottfried Koehler in April 1779 while observing a comet that appeared nearby, with Charles Messier listing both in his catalog about three days later.
Classified as an elliptical galaxy of type E5, M59 has a position angle of 163.3°, indicating a flattening of 50%. However, its isophotes deviate from a perfect ellipse, showing pointed shapes. These can be mathematically decomposed into three components, each with a different eccentricity: a main elliptical component superimposed on a flatter, disk-like feature, all embedded within a circular halo. The luminosity contributions are 62% from the pure elliptical part, 22% from the halo, and the remainder from the disk. The disk-to-elliptical light ratio is 0.25, notably lower than the typical 0.5 seen in lenticular galaxies.
At the core lies a supermassive black hole with an estimated mass of 270 million solar masses. It counter-rotates relative to the rest of the galaxy and appears bluer. Though quiescent, it is detectable as an X-ray and radio source, indicating an outflow. The nucleus contains an embedded stellar disk that is bluer (younger) than the surrounding bulge, with a blue component extending along a position angle of roughly 150°. This extended disk may result from a galactic merger followed by a starburst event.
M59 is rich in globular clusters, with an estimated population of about 2,200. It has two satellite galaxies: the ultra-compact dwarf M59-UCD3 and M59cO, a rare example of a galaxy intermediate between compact ellipticals like Messier 32 and ultra-compact dwarfs.
One supernova has been recorded in M59: SN 1939B, a Type Ia event discovered by Fritz Zwicky on 19 May 1939, reaching a peak magnitude of 11.9. The region where it occurred shows no trace of star formation, consistent with a Type Ia supernova.
- Type
- Elliptical galaxy (E5)
- Constellation
- Virgo
- Discoverer
- Johann Gottfried Koehler
- Discovery date
- April 1779
- Ngc designation
- NGC 4621
- Supernova recorded
- SN 1939B (Type Ia, peak mag. 11.9)
- Supermassive black hole mass
- 270 million solar masses
Lore & Background
Messier 59 was discovered by Johann Gottfried Koehler in April 1779 while observing a comet that appeared nearby. Charles Messier listed it in his catalogue about three days after Koehler's discovery. It is an elliptical galaxy of type E5 with a position angle of 163.3°, showing a flattening of 50%. Its isophotes deviate from perfect ellipticity, displaying pointed shapes that can be decomposed into a three-component model: a main elliptical part (62% of luminosity), a flatter disk-like feature, and a circular halo (22% of luminosity). The light ratio of the disk to the main elliptical body is 0.25, lower than the typical 0.5 in lenticular galaxies.
The core contains a supermassive black hole with an estimated mass of 270 million solar masses, which counter-rotates relative to the rest of the galaxy and appears bluer. The black hole is quiescent but detectable as an X-ray and radio source indicating an outflow. The nucleus has an embedded stellar disk that is bluer (younger) than the bulge, with a blue component stretching along a position angle of around 150°. This extended disk may result from a galactic merger followed by a starburst event. Messier 59 is very rich in globular clusters, with an estimated population of about 2,200. It has two satellites: the ultra compact dwarf galaxy M59-UCD3 and M59cO, a rare example of a galaxy between compact ellipticals and ultra compact dwarfs.
Reader's Guide
Messier 59 is significant as a member of the Virgo Cluster, providing insight into elliptical galaxy structure and evolution. Its complex morphology—deviating from a simple elliptical shape with pointed isophotes and a three-component model—challenges standard classifications. The supermassive black hole's counter-rotation and bluer color suggest a past merger event, while the embedded younger stellar disk points to a starburst episode. The galaxy's rich globular cluster population (about 2,200) and its two satellite galaxies, including the rare transitional type M59cO, make it a valuable laboratory for studying galaxy formation and hierarchical assembly. The single recorded supernova, SN 1939B, a Type Ia event discovered by Fritz Zwicky, occurred in a region with no star formation, consistent with its type. These features collectively underscore M59's role in understanding the diversity of elliptical galaxies and the processes that shape them.
Did You Know?
- Its supermassive black hole has an estimated mass of 270 million solar masses and counter-rotates relative to the galaxy.
- The galaxy has an estimated 2,200 globular clusters.
- One supernova, SN 1939B, has been recorded in M59; it was a Type Ia discovered by Fritz Zwicky.
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