Cortes-Muñoz

Identifying possibly pristine cold-flows at Cosmic Noon using quasar pairs.

Gas accretion from the Intergalactic Medium (IGM) fuels star formation at high redshift, according to Lambda-CDM theory; however, no direct observations have confirmed their presence yet. Attempts to detect such inflows in absorption against background QSOs have proven challenging, as QSOs provide just one pencil-beam per halo and the streams are predicted to have low metallicity and small covering fractions. In this talk I will present candidate cold-flows identified from a survey of z = 2-3 HI+CIV absorption line systems detected at high-spectral resolution in 13 physical and lensed QSO pairs. These pairs have projected separations ranging from sub-kiloparsec to hundreds of kiloparsecs. At such separations, signatures of cold-flow gain of angular momentum are expected as offsets in HI absorption strength and velocity between sightlines. I will present candidate cold-flows in the QSO data, assess their metal abundances and provide rough constraints on the cold-flow covering fraction.

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