SDSS-IV MaNGA: when is morphology imprinted on galaxies?

Abstract

It remains an open question as to how long ago the morphology that we see in a present-day galaxy was typically imprinted. Studies of galaxy populations at different redshifts reveal that the balance of morphologies has changed over time, but such snapshots cannot uncover the typical timescales over which individual galaxies undergo morphological transformation, nor which are the progenitors of today’s galaxies of different types. However, these studies also show a strong link between morphology and star-formation rate over a large range in redshift, which offers an alternative probe of morphological transformation. We therefore derive the evolution in star-formation rate and stellar mass of a sample of 4342 galaxies in the SDSS-IV MaNGA survey through a stellar population “fossil record” approach, and show that the average evolution of the population shows good agreement with known behaviour from previous studies. Although the correlation between a galaxy’s contemporaneous morphology and star-formation rate is strong over a large range of lookback times, we find that a galaxy’s present-day morphology only correlates with its relatively recent (∼2 Gyr) star-formation history. We therefore find strong evidence that morphological transitions to galaxies’ current appearance occurred on timescales as short as a few billion years.

The differences between mass- and light-derived structural parameters over time for MaNGA Elliptical galaxies

“…(i) The data from Suess et al (2019b) correspond to galaxies defined as quiescent at the observation's redshift, while in our case, the data correspond to the archaeological progenitors of local CLE (quiescent) galaxies, which at large look-back times are star-forming rather than quiescent (Lacerna et al 2020, see also Sánchez et al 2019 andPeterken et al 2021). How to define when a galaxy quenches its SF is a widely discussed topic in the literature, see Appendix B.…”

Size, shade or shape? The contribution of galaxies of different types to the star-formation history of the Universe from SDSS-IV MaNGA

“…However, since the sampling strategies are well-defined, each galaxy can be assigned an appropriate weighting such that any analysis can be performed on an effectively volume-limited sample (Wake et al 2017). An implementation of these weightings is described in detail by Wake et al (2017), but here -as in Peterken et al (2021) -we use weightings generated using the method implemented by Sánchez et al (2019); see also Rodriguez-Puebla et al (2020) and Calette et al (in preparation) for further details. This choice of which set of weightings to use was due to the Sánchez et al (2019) weightings being more robust at lower stellar masses and more detailed in its treatment of galaxy colour.…”

“…With its consistent radial coverage of a large sample of galaxies with varying physical properties, the integral-field spectroscopic MaNGA survey (Bundy et al 2015) (part of the fourth generation of the Sloan Digital Sky Survey; SDSS-IV; Blanton et al 2017) offers an ideal tool to investigate the link between today's galaxies and the Universe's past. In Peterken et al (2021), we explored how the stellar population fossil record can reveal the cosmic evolution of the star-formation "main sequence" and the mass function of galaxies. Here, we use the same measured star-formation histories of a large sample of galaxies to derive the star-formation history of the Universe, and make use of morphological information from both citizen science and machine learning classifications to explore the connection between present-day stellar mass, colour, and morphology to a galaxy's star-formation rate evolution over the age of the Universe.…”

SDSS IV MaNGA: Visual Morphological and Statistical Characterization of the DR15 sample

“…1 The results from applying the SPS analysis techniques to IFS observations of local galaxies, in combination with a detailed knowledge of their morphologies, open up new alternatives to investigate the processes behind galaxy formation and evolution, offering the possibility of connecting the global physical and morphological properties of galaxies to their spatially-resolved properties at the kpc scales (see, e.g., Pérez et al 2013;González Delgado et al 2015;Ibarra-Medel et al 2016;Sánchez et al 2018;Cano-Díaz et al 2019, for a recent review see Sánchez 2020, and more references therein). A detailed information on the morphological properties of the MaNGA galaxies, combined with the set of parameters derived from the IFS analysis, set the possibility of novel studies about the origin of the Hubble sequence to a new level (e.g., González Delgado et al 2016Goddard et al 2017;Peterken et al 2021).…”