NeVe 1

Lore & Background

Despite being in the relatively nearby, large Ophiuchus Cluster, NeVe 1 is heavily obscured by the Milky Way's galactic disc (the Zone of Avoidance) and is invisible to the naked eye, observable only in X-rays and infrared. When first observed in 1985, it was initially thought to be a planetary nebula within the Rho Ophiuchi cloud complex. German astronomers Thorsten Neckel and Hans Vehrenberg catalogued it as the first entry of their Atlas of Galactic Planetary Nebulae (NeVe, from their surnames). It was later incorporated into the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae in 1991. Subsequent surveys using six films from the ESO/SERC Sky Survey Atlas identified at least 4,100 galaxies including NeVe 1, and detection of luminous X-ray and radio emission indicative of an active galactic nucleus led to its reclassification as a giant galaxy beyond the Milky Way.

Using near-infrared and X-ray measurements, NeVe 1 is shown to be a large elliptical galaxy—probably one of the largest near the Milky Way, with a diameter twice that of Messier 87. Observations with the Chandra X-ray Observatory in 2010 revealed that NeVe 1 sits at the center of a comet-like structure of its host cluster, indicative of ram-pressure stripping and the merger of at least two smaller subclusters. The head of this structure sits about 4 kiloparsecs (13,000 light-years) from NeVe 1, and the galaxy is classified as a cooling core with high X-ray emission in contrast to the hot intracluster medium of the Ophiuchus Cluster.

In a 2020 paper, NeVe 1 and its surrounding region were identified as an extreme example of a giant radio fossil, with a striking concave arc terminating the X-ray halo bubble and smaller mini-lobes from further AGN activity. This concave arc is part of an enormous cavity in the intracluster medium with a diameter of at least 460 kiloparsecs (1.5×10^6 ly), corresponding to an extensive radio-emitting structure. The cavity was created by an extraordinarily large AGN outburst from NeVe 1, requiring energy on the order of 5×10^54 J—the Ophiuchus Supercluster eruption, the most energetic astronomical event known. It was five times more energetic than the outburst at MS 0735.6+7421 and 4.2 million times more energetic than GRB 221009A. The outburst likely occurred no less than 240 million years ago, generated by NeVe 1's central supermassive black hole consuming an equivalent of 270 million solar masses of material, possibly from a cannibalized dwarf galaxy. The eruption occurred slowly over millions of years, releasing as much energy as thousands of gamma-ray bursts per year. The question remains how the cool core survived; it may be due to large-scale hydrodynamic activity distributing energy via Kelvin–Helmholtz instability eddies, similar to structures in the Perseus Cluster and NGC 1275.

Reader's Guide

NeVe 1's significance lies in its hosting the Ophiuchus Supercluster eruption, the most energetic astronomical event known, with an energy output of 5×10^54 J—five times greater than the previous record holder, MS 0735.6+7421, and 4.2 million times more energetic than the most powerful gamma-ray burst, GRB 221009A. This eruption, occurring over millions of years, created an enormous cavity 460 kiloparsecs in diameter in the intracluster medium, revealing the extreme power of AGN feedback in galaxy clusters. The galaxy's location behind the Zone of Avoidance makes it a challenging but important object for studying obscured cluster dynamics and the survival of cooling cores after cataclysmic events. The discovery resulted from collaboration among observatories including the Hubble Space Telescope, Chandra X-ray Observatory, XMM Newton, Murchison Widefield Array, and Giant Metrewave Radio Telescope. NeVe 1's central black hole mass, estimated at 7×10^9 M☉ (range 2.5–19×10^9 M☉), and the eruption's energy provide key benchmarks for understanding supermassive black hole growth and the most violent processes in the universe.

Did You Know?

• NeVe 1 was initially mistaken for a planetary nebula when first observed in 1985.
• Its name comes from the surnames of German astronomers Neckel and Vehrenberg.
• The Ophiuchus Supercluster eruption released 5×10^54 J of energy, the most energetic astronomical event known.
• The central black hole of NeVe 1 may have consumed 270 million solar masses of material, possibly from a cannibalized dwarf galaxy.