FEAST: Spatially Resolved Star Formation History of the NGC 4485/NGC 4490 System and its Tidal Bridge from JWST/NIRCam Color Magnitude Diagrams

@misc{bortolini2026feast,
  title = {{FEAST: Spatially Resolved Star Formation History of the NGC 4485/NGC 4490 System and its Tidal Bridge from JWST/NIRCam Color Magnitude Diagrams}},
  author = {Giacomo Bortolini and Matteo Correnti and Angela Adamo and Michele Cignoni and Monica Tosi and Göran Östlin and Arjan Bik and Daniela Calzetti and John M. Cannon and Flavia Dell'Agli and Bruce G. Elmegreen and Helena Faustino Vieira and Kathryn Grasha and Kelsey E. Johnson and Thomas S. -Y. Lai and Drew Lapeer and Sean T. Linden and Matteo Messa and Alex Pedrini and Julia Roman-Duval and Elena Sabbi and Linda J. Smith},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.29405},
  eprint = {2610.29405},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.29405},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - FEAST: Spatially Resolved Star Formation History of the NGC 4485/NGC 4490 System and its Tidal Bridge from JWST/NIRCam Color Magnitude Diagrams
AU  - Giacomo Bortolini
AU  - Matteo Correnti
AU  - Angela Adamo
AU  - Michele Cignoni
AU  - Monica Tosi
AU  - Göran Östlin
AU  - Arjan Bik
AU  - Daniela Calzetti
AU  - John M. Cannon
AU  - Flavia Dell'Agli
AU  - Bruce G. Elmegreen
AU  - Helena Faustino Vieira
AU  - Kathryn Grasha
AU  - Kelsey E. Johnson
AU  - Thomas S. -Y. Lai
AU  - Drew Lapeer
AU  - Sean T. Linden
AU  - Matteo Messa
AU  - Alex Pedrini
AU  - Julia Roman-Duval
AU  - Elena Sabbi
AU  - Linda J. Smith
PY  - 2026
DA  - 2026/10/21
PB  - arXiv
DO  - 10.48550/arxiv.2610.29405
UR  - https://arxiv.org/abs/2610.29405
AB  - We present the spatially resolved star formation history (SFH) of the interacting, low-mass, gas-rich galaxy pair NGC 4485/NGC 4490, based on deep JWST/NIRCam imaging obtained as part of the FEAST program. Using resolved stars' near-infrared color-magnitude diagrams (CMDs) and the SFERA 2.0 CMD fitting code, we reconstruct the SFH of the system, including the tidal bridge connecting the two galaxies. We find that recent star formation is widespread across the system, extending beyond the main bodies of the galaxies into the tidal bridge and other off-center areas. In particular, a significant fraction of the recent star formation in NGC 4485 occurs outside its central region. All major regions of the system exhibit two prominent episodes of enhanced star formation, occurring around 0.5-1 Gyr and 10-30 Myr ago, with the tidal bridge showing the largest increase relative to its average star formation rate. These peaks in star formation activity occur a few hundred million years after the epochs of the first and second pericenter passages predicted by independent dynamical models, supporting a scenario in which repeated tidal interactions triggered the observed bursts through gas redistribution and compression. Our results place direct observational constraints on the formation history of NGC 4485/NGC 4490 and provide evidence for the important role of galaxy interactions in driving spatially extended, bursty star formation in low-mass galaxies.
ER  -