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Main Authors: Comparat, Johan, Merloni, Andrea, Ponti, Gabriele, Shreeram, Soumya, Zhang, Yi, Reiprich, Thomas H., Liu, Ang, Seppi, Riccardo, Zhang, Xiaoyuan, Clerc, Nicolas, Nicola, Andrina, Nandra, Kirpal, Salvato, Mara, Malavasi, Nicola
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2503.19796
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author Comparat, Johan
Merloni, Andrea
Ponti, Gabriele
Shreeram, Soumya
Zhang, Yi
Reiprich, Thomas H.
Liu, Ang
Seppi, Riccardo
Zhang, Xiaoyuan
Clerc, Nicolas
Nicola, Andrina
Nandra, Kirpal
Salvato, Mara
Malavasi, Nicola
author_facet Comparat, Johan
Merloni, Andrea
Ponti, Gabriele
Shreeram, Soumya
Zhang, Yi
Reiprich, Thomas H.
Liu, Ang
Seppi, Riccardo
Zhang, Xiaoyuan
Clerc, Nicolas
Nicola, Andrina
Nandra, Kirpal
Salvato, Mara
Malavasi, Nicola
contents This article presents the construction and validation of complete stellar mass-selected, volume-limited galaxy samples using the Legacy Survey (data release 10) galaxy catalogs, covering $\sim16,800$ deg$^2$ of extra-galactic sky, and extending to redshift $z<0.35$. We measure the correlation function of these galaxies with tiny statistical uncertainties at the percent level and systematic uncertainties up to 5\%. A 4-parameter halo occupation distribution (HOD) model is fitted to retrieve the population of host halos, yielding results on the stellar to halo mass relation consistent with the current models of galaxy formation and evolution. Using these complete galaxy samples, we measure and analyze the cross-correlation (X-corr) between galaxies and all soft X-ray photons observed by SRG/eROSITA in the 0.5-2 keV band over $\sim13,000$ deg$^2$. The cross correlation measurements have unprecedented sub-percent statistical uncertainty and ~5-10\% systematic uncertainty. An extension to the halo model is introduced to interpret the X-corr, decomposing contributions from X-ray point sources, hot gas (CGM), satellites, and the 2-halo term. For low stellar mass thresholds ($\log M^*/M_{\odot}>$ 10, 10.25, 10.5), we find that the point source emission dominates the X-corr at small separation ($r<80$kpc). Then, in the range ($80<r<2$Mpc), the emission from large halos hosting satellite galaxies dominates. Finally, on scales beyond that considered here ($r>2$Mpc), the 2-halo term becomes dominant. Interestingly, there is no scale at which the CGM dominates. In the range ($20<r<200$kpc), the CGM contributes to more than 10\% of the signal. Progressively, with the minimum stellar mass increasing, the CGM emission increases. We constrain the $M_{500c}-L_X$ scaling relation slope, $1.629^{+0.091}_{-0.089}$, at the 5\% level using the samples with the lowest mass threshold.
format Preprint
id arxiv_https___arxiv_org_abs_2503_19796
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Cross-correlation between soft X-rays and galaxies A new benchmark for galaxy evolution models
Comparat, Johan
Merloni, Andrea
Ponti, Gabriele
Shreeram, Soumya
Zhang, Yi
Reiprich, Thomas H.
Liu, Ang
Seppi, Riccardo
Zhang, Xiaoyuan
Clerc, Nicolas
Nicola, Andrina
Nandra, Kirpal
Salvato, Mara
Malavasi, Nicola
Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
High Energy Astrophysical Phenomena
This article presents the construction and validation of complete stellar mass-selected, volume-limited galaxy samples using the Legacy Survey (data release 10) galaxy catalogs, covering $\sim16,800$ deg$^2$ of extra-galactic sky, and extending to redshift $z<0.35$. We measure the correlation function of these galaxies with tiny statistical uncertainties at the percent level and systematic uncertainties up to 5\%. A 4-parameter halo occupation distribution (HOD) model is fitted to retrieve the population of host halos, yielding results on the stellar to halo mass relation consistent with the current models of galaxy formation and evolution. Using these complete galaxy samples, we measure and analyze the cross-correlation (X-corr) between galaxies and all soft X-ray photons observed by SRG/eROSITA in the 0.5-2 keV band over $\sim13,000$ deg$^2$. The cross correlation measurements have unprecedented sub-percent statistical uncertainty and ~5-10\% systematic uncertainty. An extension to the halo model is introduced to interpret the X-corr, decomposing contributions from X-ray point sources, hot gas (CGM), satellites, and the 2-halo term. For low stellar mass thresholds ($\log M^*/M_{\odot}>$ 10, 10.25, 10.5), we find that the point source emission dominates the X-corr at small separation ($r<80$kpc). Then, in the range ($80<r<2$Mpc), the emission from large halos hosting satellite galaxies dominates. Finally, on scales beyond that considered here ($r>2$Mpc), the 2-halo term becomes dominant. Interestingly, there is no scale at which the CGM dominates. In the range ($20<r<200$kpc), the CGM contributes to more than 10\% of the signal. Progressively, with the minimum stellar mass increasing, the CGM emission increases. We constrain the $M_{500c}-L_X$ scaling relation slope, $1.629^{+0.091}_{-0.089}$, at the 5\% level using the samples with the lowest mass threshold.
title Cross-correlation between soft X-rays and galaxies A new benchmark for galaxy evolution models
topic Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2503.19796