NGC 7469 is a luminous and face-on spiral galaxy. It is approximately 90,000 light-years in diameter and it lies approximately 220 million light-years from Earth in the constellation Pegasus. This galaxy dominates Webb’s picture of the month for December.
This spiral galaxy was recently studied as part of the Great Observatories All-sky LIRGs Survey (GOALS). It is a project that aims to investigate the physics of star formation, black hole growth and merging luminous infrared galaxies. Previous ESA Webb Pictures of the Month II ZW 096 and IC 1623 were also studied as part of the survey.
The active galactic nucleus (AGN) of NGC 7469 is an extremely bright central region. It is dominated by the light emitted by dust and gas as it falls into the galaxy’s central black hole. The galaxy hosts an AGN surrounded by a starburst ring at a distance of only 1500 light-years. This is why astronomers have a unique opportunity to study the relationship between AGNs and starburst activity.
NGC 7469 is one of the most studied AGNs in the sky. The system’s compact nature and the presence of a great deal of dust have made it difficult for scientists to achieve both the resolution and sensitivity required to study this relationship in the infrared. Astronomers can now use Webb to investigate the galaxy’s starburst ring, the central AGN and the gas and dust in between.
The GOALS team discovered a number of details about NGC 7469 by using Webb’s MIRI, NIRCam and NIRspec instruments. They obtained images and spectra of the object in unprecedented detail. This includes previously unseen very young star-forming clusters, pockets of very warm, turbulent molecular gas and direct evidence for the destruction of small dust grains within a few hundred light-years of the nucleus. All of these demonstrate that the AGN is influencing the surrounding interstellar medium.
Highly ionised and diffuse atomic gas appears to be exiting the nucleus at approximately 6.4 million kilometres per hour. This galactic outflow was previously identified from the ground but now revealed in stunning detail by Webb. Additional secrets of this local AGN and starburst laboratory are sure to be revealed as the rich Webb datasets are also analysed.
The striking six-pointed star perfectly aligns with the heart of NGC 7469. It is a prominent feature of this image. In contrast to the galaxy, this is an imaging artefact known as a diffraction spike caused by the bright and unresolved AGN. Diffraction spikes are patterns formed when light bends around a telescope’s sharp edges.
Webb is made up of three struts. Two of these struts are angled at 150 degrees from the vertical strut. Its primary mirror is made up of hexagonal segments with edges for light to diffract against. The diffraction spikes created by Webb’s struts partially overlap with those created by the mirrors. Both of these result in Webb’s intricate star pattern.