2026/02/11 by Jorge Sanchez Almeida, Jorge Sánchez Almeida, Ignacio Trujillo +3 · 1 voice
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #astro-ph.GA
paper · pdf · doi:10.3847/2515-5172/ae468e
arxiv published 2026/02/11 · arxiv updated 2026/02/11 · openalex created_date 2026/02/14 · openalex publication_date 2026/02/19 · openalex updated_date 2026/06/11
Abstract The linear structure reported by P. van Dokkum et al. has been proposed as either a massive stellar wake produced by a runaway supermassive black hole (SMBH) or a bulgeless edge-on galaxy. New JWST/NIRSpec IFU observations by P. van Dokkum et al. target the tip of the structure, where a SMBH would produce a bow shock, whereas a normal galaxy would host an H ii region. Using standard Baldwin–Phillips–Terlevich diagrams ([O iii ]5007/H β versus [N ii ]6583/H α and [O iii ]5007/H β versus [O ii ]6716,6731/H α ), we find that the line ratios at the tip fall on the locus of low-metallicity low-extinction H ii regions. This region does not overlap with loci typical of shocks in merging galaxies. Thus, these results are consistent with the interpretation that the linear structure is a star-forming galaxy, with the bright knot representing one of its H ii regions.