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arXiv · 2507.06696

Blowing Star Formation Away in AGN Hosts (BAH) -- III. Serendipitous discovery of a $z\sim2.9$ star-forming galaxy lensed by the galactic bulge of CGCG 012-070 using JWST NIRSpec

Rogemar A. Riffel·Carlos R. Melo-Carneiro·Gabriel Luan Souza-Oliveira·Rogério Riffel·Cristina Furlanetto·Nadia L. Zakamska·Santiago Arribas·Marina Bianchin·Ana L. Chies-Santos·José Henrique Costa-Souza·Maitê S. Z. de Mellos·Michele Perna·Thaisa Storchi-Bergmann
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Abstract

We report the detection of a gravitationally lensed galaxy by the nearby spiral galaxy CGCG 012-070 ($z = 0.048$) using Integral Field Unit (IFU) observations with the Near-Infrared Spectrograph (NIRSpec) instrument on board the James Webb Space Telescope (JWST). The lensed galaxy is identified through the flux distributions of emission lines in the rest-frame optical, consistent with a source located at a redshift of $z\sim2.89$. The system is detected in [O III]$\lambda\lambda4959,5007$, H$\beta$, and H$\alpha$ emission lines, exhibiting line ratios typical of a star-forming galaxy. The emission-line flux distributions reveal three distinct components, which are modeled using an elliptical power-law (EPL) mass profile for the lens galaxy. This model provides a good characterization of the source and reveals a disturbed star-forming morphology consistent with those of galaxies at cosmic noon. This serendipitous discovery of a rare low-redshift strong lens highlights the critical role of IFU observations in expanding the lens census and advancing our understanding of galaxy mass profiles and evolution.

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Rogemar A. Riffel, Carlos R. Melo-Carneiro, Gabriel Luan Souza-Oliveira, Rogério Riffel, Cristina Furlanetto, Nadia L. Zakamska, Santiago Arribas, Marina Bianchin, Ana L. Chies-Santos, José Henrique Costa-Souza, Maitê S. Z. de Mellos, Michele Perna, Thaisa Storchi-Bergmann. 2025-07-09. Blowing Star Formation Away in AGN Hosts (BAH) -- III. Serendipitous discovery of a $z\sim2.9$ star-forming galaxy lensed by the galactic bulge of CGCG 012-070 using JWST NIRSpec. https://doi.org/10.1051/0004-6361%2F202556329

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