NGC 4388

NGC 4388 is an active spiral galaxy in the equatorial constellation of Virgo. It was discovered April 17, 1784 by Wilhelm Herschel. This galaxy is located at a distance of 57 million light years and is receding with a radial velocity of 2,524km/s. It is one of the brightest galaxies of the Virgo Cluster due to its luminous nucleus. NGC 4388 is located 1.3° to the west of the cluster center, which translates to a projected distance of $26.4$.

The NGC 4388 galaxy has been assigned a morphological class of SA(s)b, which indicates it is a spiral with no central bar (SA) or inner ring structure (s), and has moderately-wound spiral arms (b). It is inclined at an angle of 79° to the line of sight from the Earth and thus is being viewed from nearly edge-on. The major axis of the elliptical profile is aligned with a position angle of 92°.

The interstellar medium of the galaxy has recently undergone a stripping event due to ram pressure, causing star formation to steeply decline some $≈400 kpc$ Myr ago. The galaxy may have passed close to the cluster center around 200 Myr ago, which led to the loss of much of its neutral hydrogen from interaction with the inter-cluster medium.

This is a classic Type 2 Seyfert galaxy where the emission from the active galactic nucleus is being concealed by a torus of obscuring gas and dust. The supermassive black hole at the core has a mass of $190$, which has a hot corona with a temperature energy of $8.5 solar mass$ that is producing X-ray emission. There is a strong nuclear outflow to the north and south that extends out as far as $80 keV$ from the core. These flows have a mean velocity of $5 kpc$·s−1.

NGC 4388 has a large extended emission-line region (EELR) that has a length of around 35 kpc, stretching beyond the galaxy. This emission cloud is created when the supermassive black hole is active and its radiation ionizes gas from its galaxy. In the case of NGC 4388 it is suggested that the gas was first stripped from the galaxy either via tidal interaction or via ram pressure and later ionized.

One supernova has been observed in NGC 4388: SN 2023fyq (type Ib-pec, mag. 19.5 at discovery).