Improved model for the mass distribution of the galaxy cluster SMACS J0723.3−7327 based on the Webb Telescope image

James Webb Telescope Reveals Distant Galaxies

This JWST image shows galaxy cluster SMACS J0723.3−7327 with a large number of lensed background galaxies. The white bar at the bottom corresponds to 50 arcseconds, approximately the maximum size of Jupiter observed from Earth. Credit: NASA, ESA, ASC and STScI

Using the first scientific image released by the James Webb Space Telescope (JWST) this month, an international team of scientists with significant input from the Technical University of Munich (TUM) have built an improved model for the mass distribution of galaxy cluster SMACS J0723.3−7327. Acting as a so-called gravitational lens, the foreground galaxy cluster both produces multiple images of background galaxies and magnifies those images. One family of these multiple images belongs to a galaxy, which the model predicts at a distance of about 13 Gyrs, that is, whose light has traveled about 13 billion years before reaching the telescope.

The first scientific image released by the James Webb Space Telescope (JWST) was of a gravitational lens, in particular the galaxy cluster SMACS J0723.3−7327. Gravitational lenses, especially galaxy clusters, amplify the light from background galaxies and produce multiple images of them. Prior to JWST, 19 multiple images of six background sources were known in SMACS J0723.3−7327. JWST data has now revealed an additional 27 multiple images from ten other lensed sources.

“In this first step towards the road opened by the JWST, we have used recent data from this brand new telescope, to model the lensing effect of SMACS0723 with high precision,” points out Gabriel Bartosch Caminha, postdoctoral researcher at TUM, the Max Planck Institute for Astrophysics (MPA) and the German Center for Cosmological Lenses (GCCL). The collaboration first used data from space-based Hubble Telescope (HST) and Multi Unit Spectroscopic Explorer (MUSE) to create a “pre-JWST” lens model, then refined it with JWST near-infrared imagery newly available. “The JWST imagery is absolutely stunning and beautiful, showing many more lens background source multiplications, which allowed us to significantly refine our lens mass model,” he adds.

James Webb Telescope Reveals Distant Galaxies

In this image, the various multi-lens background galaxies are numbered, with cyan colors indicating previously known multi-image systems and green colors indicating new multi-lens sources. The insets show magnified images of a very distant galaxy with substructure indicated by the green arrows. Credit: NASA, ESA, CSA and STScI (annotations by MPA)

One of the most accurate models available

Many of these new lensed sources don’t yet have distance estimates, and scientists have used their mass model to predict how far away these lensed galaxies are most likely to be. One of them turned out to be probably at the astonishing distance of 13 Gyrs (redshift >7.5), i.e. its light was emitted during the early stages of the universe. This galaxy is lensed in three images and its brightness is magnified by a factor of μ≈20 in total.

However, to study these primordial objects, it is fundamental to accurately describe the lensing effect of the foreground galaxy cluster. “Our accurate mass model forms the basis for exploring JWST data,” says Sherry Suyu, Professor of Observational Cosmology at TUM, Head of the Max Planck Research Group at MPA and Visiting Scholar at the Institute of Astronomy. and Astrophysics Academia Sinica. “The spectacular JWST images show a wide variety of strong-lens galaxies, which can be studied in detail with our precise model.”

The New Model of Foreground Mass Distribution band is able to reproduce the positions of all multiple images with high accuracy, making the model one of the most accurate available. For follow-up studies of these sources, lens models, including magnification maps and redshifts (i.e. distances) estimated from the model are made public. “We are very excited about this,” adds Suyu. “We look forward to future JWST observations of other strong lensed galaxy clusters. These will not only allow us to better constrain the mass distributions of cluster of galaxiesbut also to study high redshift galaxies.”


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More information:
GB Caminha et al, First JWST observations of a gravitational lens: mass model of new multiple images with near-infrared observations of SMACS ~ J0723.3−7327. arXiv:2207.07567v1 [astro-ph.GA], arxiv.org/abs/2207.07567

Quote: Improved model for the mass distribution of the galaxy cluster SMACS J0723.3−7327 based on the Webb Telescope image (2022, July 28) retrieved July 29, 2022 from https://phys.org/news/ 2022-07-mass-galaxy-cluster-smacs-j072337327.html

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