A preprint analysis reports evidence for a possible history in which some spiral galaxies assembled outer disks around older, quenched central systems. In the main analysis, the researchers identified 247 spiral galaxies with quenched central cores, or QCCs. The full selected sample contained 5,124 massive galaxies; when the minimum core-radius requirement was relaxed from more than 4 arcseconds to more than 2, the QCC count rose to 475.
The pattern was not simply a gradual change from center to edge. About 62% of the QCC-hosting spirals showed bimodality—a two-peaked distribution—in both D4000 and stellar velocity dispersion, the spread in the motions of their stars. Among nearly all of the bimodal galaxies, the D4000, stellar-age and velocity-dispersion gradients first steepened and then flattened near Rq, the measured QCC boundary.
The comparison behind the pattern
Researchers used spatially resolved integral-field observations from the MaNGA survey, drawing on SDSS Data Release 17 and Pipe3D-derived measurements. Pipe3D covered 10,220 galaxies from 10,245 datacubes. After central-galaxy and mass selection, the final analysis sample was 5,124 galaxies. Quenching was classified with a D4000 threshold of 1.55 and a D4000 signal-to-noise ratio above 5, and QCCs were sought only in partially quenched spirals.
The comparison groups made the question concrete: 247 QCC-hosting spirals, including 154 with bimodality and 93 without; 1,097 quenched ellipticals; 264 quenched S0s; and 1,561 star-forming spirals.
The central regions resemble quenched galaxy types
Inside the QCC-hosting spirals, the central regions were older and more metal-enriched than their outer disk regions. Outer-disk metallicity was about 0.2 dex lower—a logarithmic difference in the abundance measure—and in about 74% of the systems the outer disks had stellar velocity dispersions below half the central value. In other words, the center-to-edge contrast involved both stellar populations and the motions of stars.
The resemblance to quenched early-type galaxies appeared in structural scaling as well. On the size–mass relation, which tracks how galaxy size varies with stellar mass, QCCs closely matched quenched early-type galaxies and showed similar scatter. A second fit linked stellar velocity dispersion to stellar mass: the slope was 0.314 ± 0.019 for QCCs, 0.310 ± 0.016 for S0s and 0.233 ± 0.007 for ellipticals. The QCC value was therefore close to the S0 value and different from the elliptical value.
The kinematic comparison pointed in the same direction. Median λR profiles, a proxy for how much ordered angular momentum a system carries, were very similar for QCCs and quenched S0s. The share classified as slow rotators fell from 69.2% to 53.2% for QCCs across the reported mass bins, while the S0 share fell from 59.5% to 38.1%.
The estimated pathway depends on mass
Those comparisons were used to estimate a lenticular-to-spiral transformation rate, rather than to count directly observed changes. Using the relaxed Rq threshold of at least 2 arcseconds, the estimated rate reached about 70% near log stellar mass of 10.2, fell to about 40% near 10.7 and was below 20% above 11.2. The estimate was highest at lower stellar mass and declined as mass increased.
A separate estimate moved the other way with mass. The fraction of spirals classified as rejuvenated was about 20% near log stellar mass 10.7 and about 55% above 11.2. These figures describe the study’s inferred fractions within its selected sample; they do not show that every spiral or every quenched early-type galaxy follows the proposed route.
A persuasive pattern, but not a time-lapse
The authors interpret the combined pattern as support for rejuvenation: a quenched lenticular or other early-type central system could acquire a new spiral disk around it. The older, more metal-enriched QCCs, their break from the outer disks and their similarities to quenched early types all fit that scenario. The interpretation also suggests that quenching need not be terminal in every case, but the supplied evidence does not establish that broader conclusion.
The important boundary is that this is a comparison of observed structures, not a direct record of one galaxy changing from lenticular to spiral. The proposed sequence is inferred from present-day similarities, while the physical process behind any disk regrowth remains unmeasured. QCCs are operational regions defined through the study’s D4000 and spatial thresholds, and the count changes when the radius threshold changes. The supplied manuscript is a preprint draft dated August 27, 2026.
Paper data and sources
Original title: Evidence for the transformation from lenticular to spiral galaxies
Authors: Mengkui Zhou, Huiyuan Wang, Ran Li et al.
Journal/Repository: arXiv
Status: Preprint, not yet peer-reviewed
First online: 2026-08-26
DOI: Not available
Original paper · Full text