NGC 7469

Arp298 - HST - Potw2208a.jpg
(c) Credit: ESA/Hubble & NASA, A. Evans, R. Chandar, CC BY 4.0
Hubble Captures a Peculiar Galactic Pair

This striking image from the NASA/ESA Hubble Space Telescope showcases Arp 298, a stunning pair of interacting galaxies. Arp 298 — which comprises the two galaxies NGC 7469 and IC 5283 — lies roughly 200 million light-years from Earth in the constellation Pegasus. The larger of the two galaxies pictured here is the barred spiral galaxy NGC 7469, and IC 5283 is its diminutive companion. NGC 7469 is also host to an active, supermassive black hole and a bright ring of star clusters.

The “Arp” in this galaxy pair’s name signifies that they are listed in the Atlas of Peculiar Galaxies compiled by the astronomer Halton Arp. The Atlas of Peculiar Galaxies is a rogues’ gallery of weird and wonderful galaxies containing peculiar structures, featuring galaxies exhibiting everything from segmented spiral arms to concentric rings. This interacting galaxy pair is a familiar sight for Hubble — a portrait of the merging galaxies in Arp 298 was published in 2008.

This image of Arp 298 contains data from three separate Hubble proposals. By combining observations from three proposals, Arp 298 is captured in glorious detail in seven different filters from two of Hubble’s instruments — the Wide Field Camera 3 and the Advanced Camera for Surveys.

The process of planning Hubble observations starts with a proposal — a detailed plan of what an astronomer intends to observe and their scientific motivation for doing so. Once a year, these proposals are gathered and judged in a gruelling review process which assess their scientific merit and feasibility. Fewer than 20% of the proposed observations in any given year will make it through this process and be approved, which makes observing time with Hubble highly prized indeed.

This system will be one of the first galaxies observed with the NASA/ESA/CSA James Webb Space Telescope as part of the Director's Discretionary Early Release Science Programs in Summer 2022.

Credit:

ESA/Hubble & NASA, A. Evans, R. Chandar

Coordinates
Position (RA):  	23 3 16.34
Position (Dec): 	8° 53' 0.05"
Field of view:  	3.16 x 2.56 arcminutes
Orientation:    	North is 74.4° right of vertical

Colours & filters Band	Wavelength	Telescope
Ultraviolet UV	275 nm	Hubble Space Telescope WFC3
Optical U	336 nm	Hubble Space Telescope WFC3
Optical B	435 nm	Hubble Space Telescope ACS
Optical I	814 nm	Hubble Space Telescope ACS
Infrared Paschen Beta continuum	1.3 μm	Hubble Space Telescope WFC3
Infrared H	1.6 μm	Hubble Space Telescope WFC3
Optical H-alpha + NII	665 nm	Hubble Space Telescope WFC3

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A Wreath of Star Formation in NGC 7469 (potm2212a).jpeg
(c) ESA/Webb, NASA & CSA, L. Armus, A. S. Evans, CC BY 4.0
This image is dominated by NGC 7469, a luminous, face-on spiral galaxy approximately 90 000 light-years in diameter that lies roughly 220 million light-years from Earth in the constellation Pegasus. Its companion galaxy IC 5283 is partly visible in the lower left portion of this image.This spiral galaxy has recently been studied as part of the Great Observatories All-sky LIRGs Survey (GOALS) Early Release Science program with the NASA/ESA/CSA James Webb Space Telescope, which aims to study the physics of star formation, black hole growth, and feedback in four nearby, merging luminous infrared galaxies. Other galaxies studied as part of the survey include previous ESA/Webb Pictures of the Month II ZW 096 and IC 1623.NGC 7469 is home to an active galactic nucleus (AGN), which is an extremely bright central region that is dominated by the light emitted by dust and gas as it falls into the galaxy’s central black hole. This galaxy provides astronomers with the unique opportunity to study the relationship between AGNs and starburst activity because this particular object hosts an AGN that is surrounded by a starburst ring at a distance of a mere 1500 light-years. While NGC 7469 is one of the best studied AGNs in the sky, the compact nature of this system and the presence of a great deal of dust have made it difficult for scientists to achieve both the resolution and sensitivity needed to study this relationship in the infrared. Now, with Webb, astronomers can explore the galaxy’s starburst ring, the central AGN, and the gas and dust in between.Using Webb’s MIRI, NIRCam and NIRspec instruments to obtain images and spectra of NGC 7469 in unprecedented detail, the GOALS team has uncovered a number of details about the object. This includes very young star-forming clusters never seen before, as well as 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 — proving that the AGN is impacting the surrounding interstellar medium. Furthermore, highly ionised, diffuse atomic gas seems to be exiting the nucleus at roughly 6.4 million kilometres per hour — part of a galactic outflow that had previously been identified, but is now revealed in stunning detail with Webb. With analysis of the rich Webb datasets still underway, additional secrets of this local AGN and starburst laboratory are sure to be revealed.A prominent feature of this image is the striking six-pointed star that perfectly aligns with the heart of NGC 7469. Unlike the galaxy, this is not a real celestial object, but an imaging artifact known as a diffraction spike, caused by the bright, unresolved AGN. Diffraction spikes are patterns produced as light bends around the sharp edges of a telescope. Webb’s primary mirror is composed of hexagonal segments that each contain edges for light to diffract against, giving six bright spikes. There are also two shorter, fainter spikes, which are created by diffraction from the vertical strut that helps support Webb’s secondary mirror.[Image Description: This image shows a spiral galaxy that is dominated by a bright central region. The galaxy has blue-purple hues with orange-red regions filled with stars. Also visible is large diffraction spike, which appears as a star pattern over the central region of the galaxy. Lots of stars and galaxies fill the background scene.]Links