VENUS: When red meets blue
Abstract
We report the discovery of a doubly imaged little red dot (LRD) candidate behind the galaxy cluster Abell 383, which we dub A383-LRD1. Initially classified as a dropout galaxy in HST imaging with several ground-based emission line detections placing it at z spec = 6.027, new JWST/NIRCam observations taken as part of the cycle 4 VENUS survey now reveal that the source consists of two underlying components. These consist of a red point-source with a V-shaped SED consistent with LRD selection criteria and a nearby (∼380 pc) compact blue companion, which was the main contributor to the previous rest-frame UV detections. Based on lensing symmetry and its SED, the LRD appears to lie at a similar redshift as well. The magnification of the two images of A383-LRD1 is μ A = 16.2 ± 1.2 and μ B = 9.0 ± 0.6, respectively, and the predicted time delay between them is Δ t grav = 5.20 ± 0.14 yr (∼0.7 yr in the rest-frame). After correcting for the lensing magnification, we derived an absolute magnitude of M UV, LRD = −16.8 ± 0.3 for the LRD and M UV, BC = −18.2 ± 0.2 for the blue companion. We performed SED fits to both components, revealing the LRD to show the best fit with a black hole star (BH*) model and a substantial host galaxy, along with the blue companion with an extremely young, emission-line dominated star-forming nebula. If it is verified spectroscopically in the future, A383-LRD1 would represent the second known multiply imaged LRD detected to date, following A2744-QSO1. To our knowledge, it would also stand as the first LRD system with a confirmed detection of [C II ] λ 158 μm emission from ALMA observations. Thanks to the lensing magnification, this system opens a unique door to studying the relation between a LRD, its host galaxy, and its environment. It represents a prime candidate for deep JWST spectroscopy and high-resolution ALMA follow-up observations.
Fields of Study & Subjects
Galaxies: Formation
Evolution
Phenomena
Astronomy and Astrophysical Research
Astrophysical Phenomena and Observations
Publication details
- Journal / source
- Astronomy and Astrophysics
- Publisher
- EDP Sciences
- Volume
- 710
- Pages
- A226–A226
- Publication date
- 29 April 2026
- Language
- EN