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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The ability to resolve all processes which drive galaxy formation is one ofthe most fundamental goals in extragalactic astronomy. While star formationrates and the merger history are now measured with increasingly high certainty,the role of gas accretion from the intergalactic medium in supplying gas forstar formation still remains largely unknown. We present in this paper indirectevidence for the accretion of gas into massive galaxies with initial stellarmasses M_*>10^{11} M_sol and following the same merger adjusted co-movingnumber density at lower redshifts during the epoch 1.5 < z < 3, using resultsfrom the GOODS NICMOS Survey (GNS). We show that the measured gas massfractions of these massive galaxies are inconsistent with the observed starformation history for the same galaxy population. We further demonstrate thatthis additional gas mass cannot be accounted for by cold gas delivered throughminor and major mergers. We also consider the effects of gas outflows and gasrecycling due to stellar evolution in these calculations. We argue that tosustain star formation at the observed rates there must be additional methodsfor increasing the cold gas mass, and that the likeliest method forestablishing this supply of gas is by accretion from the intergalactic medium.We calculate that the average gas mass accretion rate into these massivegalaxies between 1.5 < z < 3.0, is \dot{M} = 96+/-19 M_sol/yr after accountingfor outflowing gas. We show that during this epoch, and for these very massivegalaxies, 49+/-20% of baryonic mass assembly is a result of gas accretion andunresolved mergers. However, 66+/-20% of all star formation in this epoch isthe result of gas accretion. This reveals that for the most massive galaxies at1.5< z< 3 gas accretion is the dominant method for instigating new stellar massassembly.

Gas Accretion as a Dominant Formation Mode in Massive Galaxies from the GOODS NICMOS Survey