ESA printed this unique article on December 21, 2022. Learn the original article here. Edits by EarthSky.
A wreath of star formation
The luminous, face-on spiral galaxy NGC 7469 is on the coronary heart of Webb’s image of the month for December. Roughly 90,000 light-years in diameter, the galaxy lies roughly 220 million light-years from Earth within the constellation Pegasus.
The Nice Observatories All-sky LIRGs Survey (GOALS) lately studied this spiral galaxy. The objective of “GOALS” is to check the physics of star formation, black hole development and suggestions in 4 close by, merging luminous infrared galaxies. Different galaxies which might be part of the survey embody earlier ESA Webb Photos of the Month II ZW 096 and IC 1623.
Starry spiral NGC 7469
NGC 7469 is residence to an lively galactic nucleus (AGN), which is a particularly brilliant central area dominated by the sunshine emitted by dust and fuel because it falls into the galaxy’s central black hole. This galaxy supplies astronomers with the distinctive alternative to check the connection between AGNs and starburst exercise. That’s as a result of NGC 7469 hosts an AGN that’s surrounded by a starburst ring at a distance of a mere 1,500 light-years.
Whereas NGC 7469 is without doubt one of the finest studied AGNs within the sky, the compact nature of this method and the presence of an excessive amount of dust have made it troublesome for scientists to attain each the decision and sensitivity wanted to check this relationship within the infrared. Now, with Webb, astronomers can discover the galaxy’s starburst ring, the central AGN, and the fuel and dust in between.
New discoveries within the wreath of star formation
Webb’s MIRI, NIRCam and NIRspec devices obtained photographs and spectra of NGC 7469 in unprecedented element. The GOALS group uncovered numerous discoveries concerning the object. This contains very younger star-forming clusters by no means seen earlier than and pockets of very heat, turbulent molecular fuel.
The group additionally noticed direct proof for the destruction of small dust grains inside a couple of hundred light-years of the nucleus. This proves that the AGN is impacting the encompassing interstellar medium. Moreover, extremely ionized, diffuse atomic fuel appears to be exiting the nucleus at roughly 4 million miles per hour (6.4 million kilometers per hour). This speedy fuel is a part of a galactic outflow that scientists beforehand recognized from the bottom, however now they see it in beautiful element with Webb. They count on to be taught extra of NGC 7469’s secrets and techniques as evaluation of the wealthy Webb datasets proceed.
Why is there a diffraction spike?
A outstanding characteristic of this picture is the placing six-pointed star that completely aligns with the guts of NGC 7469. In contrast to the galaxy, this isn’t an actual celestial object, however an imaging artifact often known as a diffraction spike. On this case, the brilliant, unresolved galactic core causes the diffraction spike.
Diffraction spikes are patterns produced as gentle bends across the sharp edges of a telescope. Webb has three struts, with two angled at 150 levels from its vertical strut. Plus, its major mirror consists of hexagonal segments that every include edges for gentle to diffract towards. Engineers designed Webb’s struts in order that their diffraction spikes partially overlap with these created by the mirrors. Each of those result in Webb’s complicated “star” sample.
Backside line: The Webb space telescope captured this picture of the spiral galaxy NGC 7469 in Pegasus. You possibly can see a wreath of star formation within the ring across the galaxy’s central black hole.
