The SAMI Galaxy Survey: Spatially Resolving the Main Sequence of Star Formation
Abstract
We present the ~800 star formation rate maps for the SAMI Galaxy Survey based on H{\alpha} emission maps, corrected for dust attenuation via the Balmer decrement, that are included in the SAMI Public Data Release 1. We mask out spaxels contaminated by non-stellar emission using the [O III]/H{\beta}, [N II]/H{\alpha}, [S II]/H{\alpha}, and [O I]/H{\alpha} line ratios. Using these maps, we examine the global and resolved star-forming main sequences of SAMI galaxies as a function of morphology, environmental density, and stellar mass. Galaxies further below the star-forming main sequence are more likely to have flatter star formation profiles. Early-type galaxies split into two populations with similar stellar masses and central stellar mass surface densities. The main sequence population has centrally-concentrated star formation similar to late-type galaxies, while galaxies >3{\sigma} below the main sequence show significantly reduced star formation most strikingly in the nuclear regions. The split populations support a two-step quenching mechanism, wherein halo mass first cuts off the gas supply and remaining gas continues to form stars until the local stellar mass surface density can stabilize the reduced remaining fuel against further star formation. Across all morphologies, galaxies in denser environments show a decreased specific star formation rate from the outside in, supporting an environmental cause for quenching, such as ram-pressure stripping or galaxy interactions.
Keywords
Cite
@article{arxiv.1801.04283,
title = {The SAMI Galaxy Survey: Spatially Resolving the Main Sequence of Star Formation},
author = {Anne M. Medling and Luca Cortese and Scott M. Croom and Andrew W. Green and Brent Groves and Elise Hampton and I-Ting Ho and Luke J. M. Davies and Lisa J. Kewley and Amanda J. Moffett and Adam L. Schaefer and Edward Taylor and Tayyaba Zafar and Kenji Bekki and Joss Bland-Hawthorn and Jessica V. Bloom and Sarah Brough and Julia J. Bryant and Barbara Catinella and Gerald Cecil and Matthew Colless and Warrick J. Couch and Michael J. Drinkwater and Simon P. Driver and Christoph Federrath and Caroline Foster and Gregory Goldstein and Michael Goodwin and Andrew Hopkins and J. S. Lawrence and Sarah K. Leslie and Geraint F. Lewis and Nuria P. F. Lorente and Matt S. Owers and Richard McDermid and Samuel N. Richards and Robert Sharp and Nicholas Scott and Sarah M. Sweet and Dan S. Taranu and Edoardo Tescari and Chiara Tonini and Jesse van de Sande and C. Jakob Walcher and Angus Wright},
journal= {arXiv preprint arXiv:1801.04283},
year = {2018}
}
Comments
accepted to MNRAS