English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The presence of extremely compact galaxies at z~2 and their subsequent growthin physical size has been the cause of much puzzlement. We revisit the questionusing deep infrared Wide Field Camera 3 data to probe the rest-frame opticalstructure of 935 host galaxies selected with 0.4<z<2.5 and stellar masses M* >10^10.7 Msol using optical and near-infrared photometry in the UKIRT Ultra DeepSurvey and GOODS-South fields of the CANDELS survey. At each redshift, the mostcompact sources are those with little or no star formation, and we find thatthe mean size of these systems grows by a factor of 3.5 +- 0.3 over thisredshift interval. The new data are sufficiently deep to enable us to identifycompanions to these hosts whose stellar masses are ten times smaller, whilestill yielding suitably accurate photometric redshifts to define a likelyphysical association. By searching for faint companions around 404 quiescenthosts within a projected physical annulus 10 < R < 30 kpc/h, we estimate theminor merger rate over the redshift range 0.4 < z < 2. After correcting forcontamination from projected pairs, we find that 13-18% of quiescent hosts havelikely physical companions with stellar mass ratios of 0.1 or greater. Mergersof these companions will typically increase the host mass by 6+-2% per mergertimescale. We estimate the minimum growth rate necessary to explain thedeclining abundance of compact galaxies. Using a simple model of mergingmotivated by recent numerical simulations, we then assess whether mergers ofthe faint companions with their hosts are sufficient to explain this minimalrate. We find that mergers with mass ratios > 0.1 may explain most of the sizeevolution observed at z >~ 1 if a relatively short merger timescale is assumed,but the rapid growth seen at higher redshift likely requires additionalphysical processes.

Can Minor Merging Account for the Size Growth of Quiescent Galaxies? New Results from the CANDELS Survey