Sharpening quasar absorption lines with ESPRESSO: Temperature of warm gas at $z\sim 2$, constraints on the Mg isotopic ratio, and structure of cold gas at $z\sim 0.5$

P. Noterdaeme, S. Balashev, C. Ledoux +7

We present a high-resolution (R=140,000) spectrum of the bright quasar HE0001-2340 (z=2.26), obtained with ESPRESSO at the Very Large Telescope. We analyse three systems at z=0.45,…