Webb's First Deep Field (NIRCam Image)

 Webb's First Deep Field (NIRCam Image)

Thousands of galaxies flood this near-infrared image of galaxy cluster SMACS 0723. High-resolution imaging from NASA’s James Webb Space Telescope combined with a natural effect known as gravitational lensing made this finely detailed image possible.

First, focus on the galaxies responsible for the lensing: the bright white elliptical galaxy at the center of the image and smaller white galaxies throughout the image. Bound together by gravity in a galaxy cluster, they are bending the light from galaxies that appear in the vast distances behind them. The combined mass of the galaxies and dark matter act as a cosmic telescope, creating magnified, contorted, and sometimes mirrored images of individual galaxies.

Clear examples of mirroring are found in the prominent orange arcs to the left and right of the brightest cluster galaxy. These are lensed galaxies – each individual galaxy is shown twice in one arc. Webb’s image has fully revealed their bright cores, which are filled with stars, along with orange star clusters along their edges.

Not all galaxies in this field are mirrored – some are stretched. Others appear scattered by interactions with other galaxies, leaving trails of stars behind them.

Webb has refined the level of detail we can observe throughout this field. Very diffuse galaxies appear like collections of loosely bound dandelion seeds aloft in a breeze. Individual “pods” of star formation practically bloom within some of the most distant galaxies – the clearest, most detailed views of star clusters in the early universe so far.

One galaxy speckled with star clusters appears near the bottom end of the bright central star’s vertical diffraction spike – just to the right of a long orange arc. The long, thin ladybug-like galaxy is flecked with pockets of star formation. Draw a line between its “wings” to roughly match up its star clusters, mirrored top to bottom. Because this galaxy is so magnified and its individual star clusters are so crisp, researchers will be able to study it in exquisite detail, which wasn’t previously possible for galaxies this distant.

The galaxies in this scene that are farthest away – the tiniest galaxies that are located well behind the cluster – look nothing like the spiral and elliptical galaxies observed in the local universe. They are much clumpier and more irregular. Webb’s highly detailed image may help researchers measure the ages and masses of star clusters within these distant galaxies. This might lead to more accurate models of galaxies that existed at cosmic “spring,” when galaxies were sprouting tiny “buds” of new growth, actively interacting and merging, and had yet to develop into larger spirals. Ultimately, Webb’s upcoming observations will help astronomers better understand how galaxies form and grow in the early universe.

NIRCam was built by a team at the University of Arizona and Lockheed Martin’s Advanced Technology Center.

For a full array of Webb’s first images and spectra, including downloadable files, please visit: https://webbtelescope.org/news/first-images




About The Object
Object Name SMACS 0723-73 (1RXS J072319.7-732735, SMACS J0723.3-7327)
Object Description Lensing Galaxy Cluster
R.A. Position 07:23:19.5
Dec. Position -73:27:15.6
Constellation Volans
Distance Redshift of cluster is z=0.39 (about 4.24 billion light-years)
Dimensions Image is about 2.4 arcmin across
About The Data
Data Description This image was created with Webb data from proposal . It is part of Webb Early Release Observations. The Early Release Observations and associated materials were developed, executed, and compiled by the ERO production team: Jaclyn Barrientes, Claire Blome, Hannah Braun, Matthew Brown, Margaret Carruthers, Dan Coe, Joseph DePasquale, Nestor Espinoza, Macarena Garcia Marin, Karl Gordon, Alaina Henry, Leah Hustak, Andi James, Ann Jenkins, Anton Koekemoer, Stephanie LaMassa, David Law, Alexandra Lockwood, Amaya Moro-Martin, Susan Mullally, Alyssa Pagan, Dani Player, Klaus Pontoppidan, Charles Proffitt, Christine Pulliam, Leah Ramsay, Swara Ravindranath, Neill Reid, Massimo Robberto, Elena Sabbi, Leonardo Ubeda.  The EROs were also made possible by the foundational efforts and support from the JWST instruments, STScI planning and scheduling, Data Management teams, and Office of Public Outreach.
Instrument NIRCam
Exposure Dates 7 June 2022
Filters  F090W, F150W, F200W, F277W, F356W, F444W
About The Image
Color Info These images are a composite of separate exposures acquired by the James Webb Space Telescope using the NIRCam instrument. Several filters were used to sample broad wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are:   Red: F444W Orange: F356W  Green: F200W + F277W Blue: F090W + F150W
Compass Image Thousands of small galaxies appear across this view. Their colors vary. Some are shades of orange, while others are white. Most appear as fuzzy ovals, but a few have distinct spiral arms. In front of the galaxies are several foreground stars. Most appear blue, and the bright stars have diffraction spikes, forming an eight-pointed star shape. There are also many thin, long, orange arcs that curve around the center of the image. Please reference the extended text description for more details.
About The Object
Object Name A name or catalog number that astronomers use to identify an astronomical object.
Object Description The type of astronomical object.
R.A. Position Right ascension – analogous to longitude – is one component of an object's position.
Dec. Position Declination – analogous to latitude – is one component of an object's position.
Constellation One of 88 recognized regions of the celestial sphere in which the object appears.
Distance The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.
Dimensions The physical size of the object or the apparent angle it subtends on the sky.
About The Data
Data Description
  • Proposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
  • Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.
Instrument The science instrument used to produce the data.
Exposure Dates The date(s) that the telescope made its observations and the total exposure time.
Filters The camera filters that were used in the science observations.
About The Image
Image Credit The primary individuals and institutions responsible for the content.
Publication Date The date and time the release content became public.
Color Info A brief description of the methods used to convert telescope data into the color image being presented.
Orientation The rotation of the image on the sky with respect to the north pole of the celestial sphere.