Produção Nacional
Revisado por pares
Bulgeless galaxies in the COSMOS field: environment and star formation evolution at z < 1
2017; Oxford University Press; Volume: 475; Issue: 1 Linguagem: Inglês
10.1093/mnras/stx3165
ISSN1365-2966
AutoresM. Grossi, C. A. C. Fernandes, David Sobral, J. Afonso, Eduardo Telles, L. Bizzocchi, Ana Paulino-Afonso, I. Matute,
Tópico(s)Astrophysics and Star Formation Studies
ResumoCombining the catalogue of galaxy morphologies in the COSMOS field and the sample of H$α$ emitters at redshifts $z=0.4$ and $z=0.84$ of the HiZELS survey, we selected $\sim$ 220 star-forming bulgeless systems (Sérsic index $n \leq 1.5$) at both epochs. We present their star formation properties and we investigate their contribution to the star formation rate function (SFRF) and global star formation rate density (SFRD) at $z < 1$. For comparison, we also analyse H$α$ emitters with more structurally evolved morphologies that we split into two classes according to their Sérsic index $n$: intermediate ($ 1.5 < n \leq 3 $) and bulge-dominated ($n > 3$). At both redshifts the SFRF is dominated by the contribution of bulgeless galaxies and we show that they account for more than 60% of the cosmic SFRD at $z < 1$. The decrease of the SFRD with redshift is common to the three morphological types but it is stronger for bulge-dominated systems. Star-forming bulgeless systems are mostly located in regions of low to intermediate galaxy densities ($Σ\sim 1 - 4$ Mpc$^{-2}$) typical of field-like and filament-like environments and their specific star formation rates (sSFRs) do not appear to vary strongly with local galaxy density. Only few bulgeless galaxies in our sample have high (sSFR $>$ 10$^{-9}$ yr$^{-1}$) and these are mainly low-mass systems. Above $M_* \sim 10^{10}$ M$_{\odot}$ bulgeless are evolving at a "normal" rate (10$^{-9}$ yr$^{-1}
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