Constraining the Size of the Circumgalactic Medium Using the Transverse Autocorrelation Function of C IV Absorbers in Paired Quasar Spectra

The circumgalactic medium (CGM) plays a vital role in the formation and evolution of galaxies, acting as a lifeline between galaxies and the surrounding intergalactic medium (IGM). In this study we leverage a unique sample of quasar pairs to investigate the properties of the CGM with absorption line tomography. We present a new sample of medium resolution Keck/ESI, Magellan/MagE, and VLT/XSHOOTER spectra of 29 quasar pairs at redshift \(2 < z < 3\). We supplement the sample with additional spectra of 32 pairs from the literature, creating a catalog of 61 quasar pairs with angular separations between 1.7" and 132.9" and projected physical separations (\(r_\perp\)) between 14 kpc and 887 kpc. We construct a catalog of 906 metal-line absorption doublets of C IV (\(\lambda\lambda 1548, 1550\)) with equivalent widths ranging from 6 mÅ \(\leq W_{r, 1550} \leq 2053\) mÅ. The best fit linear model to the log-space equivalent width frequency distribution (\(\log f(W_r) = m\log(W_{r}) + b\)) of the sample yields coefficients of \(m=-1.44\pm0.16\) and \(b=-0.43\pm0.16\). To constrain the projected extent of C IV, we calculate the transverse autocorrelation function. The flattening of the autocorrelation function at low \(r_\perp\) provides a lower limit for the coherence length of the metal enriched CGM - on the order of 200 \(h^{-1}\) comoving kpc. This physical size constraint allows us to refine our understanding of the metals in the CGM, where the extent of C IV in the CGM depends on gas flows, feedback, timescale of metal injection and mixing, and the mass of the host galaxies.