The cross-correlation of galaxies in absorption with the Lyman $\alpha$ forest

Abstract

We present the first clustering measurement of Strong Blended Lyman $\alpha$ (SBLA) absorption systems by measuring their cross-correlation with the Lyman $\alpha$ forest. SBLAs are a new population of absorbers detected within the Lyman $\alpha$ forest. We find a bias of $2.329\pm 0.057$, consistent with that of Damped Lyman $\alpha$ absorbers (DLAs). For DLAs, we recover a bias of $2.331\pm 0.057$ larger than previously reported (Pérez-Ràfols et al. 2018b). We also find a redshift space distortion parameter $\beta =0.417\pm 0.010$, also consistent with the recovered value for DLAs ($\beta =0.416\pm 0.010$). This is consistent with SBLA and DLA systems tracing different portions of the circumgalactic medium of a broadly common population of galaxies. Given these common clustering properties, we combined them to perform a cross-correlation of galaxies in absorption with the Ly$\alpha$ forest. We find that the BAO scale uncertainty of this new measurement is $1.75\times$ that of Ly$\alpha$ auto-correlation and $1.6\times$ that of the quasar cross-correlation with the Ly$\alpha$ forest. We note that the current preferred metal contamination model for fitting the correlation functions with respect to the Ly$\alpha$ forest is not realistic enough for SBLA systems, likely due to their status as high redshift precision sites of high metal enrichment. Mock spectra including SBLA systems and their associated metal absorption are required to understand this sample fully. We conclude that SBLAs have the potential to complement the standard Ly$\alpha$ cosmological analyses in future surveys.

accepted in MNRAS; 15 pages, 6 figures, 3 tables

References in corpus (9)

• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Cosmological Implications from two Decades of Spectroscopic Surveys at the Apache Point observatory
• Baryon Acoustic Oscillations in the Lyα forest of BOSS DR11 quasars
• Baryon Acoustic Oscillations in the Ly-α forest of BOSS quasars
• Baryon acoustic oscillations from the complete SDSS-III Ly$\alpha$-quasar cross-correlation function at $z=2.4$
• The SDSS-DR12 large-scale cross-correlation of Damped Lyman Alpha Systems with the Lyman Alpha Forest
• Cosmology beyond BAO from the 3D distribution of the Lyman-$\alpha$ forest
• The extended Baryon Oscillation Spectroscopic Survey: measuring the cross-correlation between the MgII flux transmission field and quasars and galaxies at $z=0.59$
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: The Damped Lyman-$\alpha$ systems Catalog
• The C IV forest as a probe of baryon acoustic oscillations

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• The miniJPAS survey quasar selection V: combined algorithm
• MUSE Analysis of Gas around Galaxies (MAGG) -- VII. Emission line galaxies near strong blended Ly$\alpha$ absorption systems at $z\gtrsim 3$