Stellar Populations of Nine Passive Spiral Galaxies from the CALIFA Survey: Are They Progenitors of S0s?
We investigate the stellar population properties of passive spiral galaxies in the Calar Alto Legacy Integral Field Area survey. Nine spiral galaxies that have (NUV-r > 5 (NUV is near-UV filter) and no/weak nebular emission lines in their spectra are selected as passive spirals. Our passive spirals lie in the redshift range of 0.001 < z < 0.021 and have a stellar mass range of 10.2 < log(M ⋆/M ☉) < 10.8. They clearly lie in the domain of early-type galaxies in the Wide-field Infrared Survey Explorer infrared color-color diagram. We analyze the stellar populations out to two effective radii, using the best-fitting model to the measured absorption line-strength indices in the Lick Observatory Image Dissector Scanner system. We find that stellar populations of the passive spirals span a wide range, even in their centers, and hardly show any common trend among themselves either. We compare the passive spirals with Lenticular (S0-type) galaxies (S0s) selected in the same mass range. S0s cover a wide range in age, metallicity, and [α/Fe], and stellar populations of the passive spirals are encompassed in the spread of the S0 properties. However, the distribution of passive spirals are skewed toward higher values of metallicity, lower [α/Fe], and younger ages at all radii. These results show that passive spirals are possibly related to S0s in their stellar populations. We infer that the diversity in the stellar populations of S0s may result from different evolutionary pathways of S0 formation, and passive spirals may be one of the possible channels.
The Astrophysical Journal
- Pub Date:
- August 2019
- galaxies: clusters: general;
- galaxies: evolution;
- galaxies: spiral;
- galaxies: stellar content;
- Astrophysics - Astrophysics of Galaxies
- 15 pages, 8 figures, accepted