Unscrambling the lensed galaxies in JWST images behind SMACS0723 (2207.07102v4)

Abstract: The first deep field images from the James Webb Space Telescope (JWST) of the galaxy cluster SMACS~J0723.3-7327 reveal a wealth of new lensed images at uncharted infrared wavelengths, with unprecedented depth and resolution. Here we securely identify 14 new sets of multiply imaged galaxies totalling 42 images, adding to the five sets of bright and multiply-imaged galaxies already known from Hubble Space Telescope data. We find examples of arcs crossing critical curves, allowing detailed community follow-up, such as JWST spectroscopy for precise redshift determinations, and measurements of the chemical abundances and of the detailed internal gas dynamics of very distant, young galaxies. One such arc contains a pair of compact knots that are magnified by a factor of hundreds, and features a microlensed transient. We also detect an Einstein cross candidate only visible thanks to JWST's superb resolution. Our parametric lens model is available through the following link: https://www.dropbox.com/sh/gwup2lvks0jsqe5/AAC2RRSKce0aX-lIFCc9vhBXa?dl=0, and will be regularly updated using additional spectroscopic redshifts. The model is constrained by 16 of these sets of multiply imaged galaxies, three of which have spectroscopic redshifts, and reproduces the multiple images to better than an rms of $0.5^{\prime \prime}$, allowing for accurate magnification estimates of high-redshift galaxies. The intracluster light extends beyond the cluster members, exhibiting large-scale features that suggest a significant past dynamical disturbance. This work represents a first taste of the enhanced power JWST will have for lensing-related science.

• The paper identifies 14 new multiply imaged galaxy sets, adding 42 individual images to prior HST findings.
• The paper refines a parametric lensing model using 16 image systems, enhancing redshift and magnification estimates.
• The paper reveals distinct arcs crossing critical curves and an Einstein cross candidate, enabling focused microlensing studies.

An Analysis of Lensed Galaxies in JWST Images Behind SMACS 0723

The paper examines the recent findings from the James Webb Space Telescope (JWST) regarding the galaxy cluster SMACS J0723.3-7327 (SMACS0723), which has provided unprecedented insights into the spatial distribution of lensed galaxies at infrared wavelengths. The authors report the identification of 14 new sets of multiply imaged galaxies, resulting in 42 individual images. These add to the previously established five sets using Hubble Space Telescope (HST) data.

Methodology and Models

The research utilizes a parametric model for strong gravitational lensing (SL), which refines earlier models by incorporating higher-resolution data from JWST. This model identifies multiple image systems through visual inspection alongside photometric and spectroscopic redshifts. The parametric lens model is constrained by 16 sets of multiply imaged galaxies, enhancing the accuracy of high-redshift galaxy magnification estimates.

Key Findings

• Identification of 14 new sets of multiply-imaged galaxies behind SMACS0723, totaling 42 images.
• The discovery of unique lensed features, such as arcs crossing critical curves, which allow for detailed follow-up studies and spectroscopic analysis of high-redshift galaxies.
• A parametric lensing model that is constrained by various image systems, providing magnification and redshift prediction capabilities.

A notable aspect of the findings is the detection of arcs crossing critical curves, facilitating high-magnification paper opportunities. One such arc comprises a pair of compact knots with magnification factors on the order of hundreds, offering a rare opportunity to paper potential microlensing events. The team also identifies an Einstein cross candidate, observed thanks to JWST's resolution capabilities.

Implications

The data from JWST demonstrates its enhanced capability for gravitational lensing studies, providing an avenue for precise redshift determinations and detailed analyses of galaxy composition and dynamics at high redshifts. This advancement has the potential to significantly impact our understanding of the early Universe's galaxies and their evolution.

The parametric model refines our lensing analysis algorithm, allowing for more precise magnification and mass mappings. Moreover, this research underscores the significance of JWST in advancing the field of extragalactic astronomy.

Future Directions

The implications of this paper suggest several future research avenues:

• Continued monitoring and follow-up observations utilizing JWST's capabilities to further investigate identified lensed features and potential microlensing events.
• Refinements to lensing models with the addition of further spectroscopic redshift data, potentially from additional JWST observations or other telescopes, to enhance accuracy and reliability.
• Application of these methodologies to other deep field observations to expand our understanding of the Universe's structure and evolution.

In conclusion, the findings from JWST observations of SMACS0723 represent a significant enhancement in our capacity to paper the structure of the Universe through gravitational lensing. The identification of multiple lensed galaxies and novel lensed features offers new insights into galaxy formation and composition at previously unexplored depths and resolutions. These insights pave the way for future research, leveraging JWST's advanced capabilities to unravel the complexities of the cosmos.