The cosmic assembly of stellar haloes in massive early-type Galaxies

Buitrago, Fernando; Trujillo, I.; Curtis-Lake, Emma; Montes, Mireia; Cooper, Andrew P.; Bruce, Victoria A.; Pérez-González, Pablo G.; Cirasuolo, Michele
Bibliographical reference

Monthly Notices of the Royal Astronomical Society, Volume 466, Issue 4, p.4888-4903

Advertised on:
4
2017
Number of authors
8
IAC number of authors
1
Citations
42
Refereed citations
39
Description
Using the exquisite depth of the Hubble Ultra Deep Field (HUDF12 programme) data set, we explore the ongoing assembly of the outermost regions of the most massive galaxies (Mstellar ≥ 5× 1010 M⊙) at z ≤ 1. The outskirts of massive objects, particularly early-type Galaxies (ETGs), are expected to suffer a dramatic transformation across cosmic time due to continuous accretion of small galaxies. HUDF imaging allows us to study this process at intermediate redshifts in six massive galaxies, exploring the individual surface brightness profiles out to ∼25 effective radii. We find that 5-20 per cent of the total stellar mass for the galaxies in our sample is contained within 10 < R < 50 kpc. These values are in close agreement with numerical simulations, and higher than those reported for local late-type galaxies (≲5 per cent). The fraction of stellar mass stored in the outer envelopes/haloes of massive ETGs increases with decreasing redshift, being 28.7 per cent at = 0.1, 15.1 per cent at = 0.65 and 3.5 per cent at = 2. The fraction of mass in diffuse features linked with ongoing minor merger events is >1-2 per cent, very similar to predictions based on observed close pair counts. Therefore, the results for our small albeit meaningful sample suggest that the size and mass growth of the most massive galaxies have been solely driven by minor and major merging from z = 1 to today.
Related projects
Group members
Traces of Galaxy Formation: Stellar populations, Dynamics and Morphology
We are a large, diverse, and very active research group aiming to provide a comprehensive picture for the formation of galaxies in the Universe. Rooted in detailed stellar population analysis, we are constantly exploring and developing new tools and ideas to understand how galaxies came to be what we now observe.
Ignacio
Martín Navarro