Mass calibration of the CODEX cluster sample using SPIDERS spectroscopy – II. The X-ray luminosity–mass relation

Monthly Notices of the Royal Astronomical Society

Finoguenov

et al. 2021

Self Cite

SPIDERS is the spectroscopic follow-up effort of the Sloan Digital Sky Survey IV (SDSS-IV) project for the identification of X-ray selected galaxy clusters. We present our catalogue of 2740 visually inspected galaxy clusters as part of the SDSS Data Release 16 (DR16). Here we detail the target selection, our methods for validation of the candidate clusters, performance of the survey, the construction of the final sample, and a full description of what is found in the catalogue. Of the sample, the median number of members per cluster is approximately 10, with 818 having 15 or greater. We find that we are capable of validating over 99 per cent of clusters when five redshifts are obtained below z < 0.3 and when nine redshifts are obtained above z > 0.3. We discuss the improvements in this catalogue’s identification of cluster using 33 340 redshifts, with Δzphot/Δzspec ∼ 100, over other photometric and spectroscopic surveys, as well as presenting an update to previous (σ–LX) and (σ–λ) relations. Finally, we present our cosmological constraints derived using the velocity dispersion function.

Section: S U M M a Rysupporting

confidence: 92%

Section: O S M O L O G Y C O N S T R a I N T Ssupporting

confidence: 68%

Section: T H E C Ata L O G U Ementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

SPIDERS: an overview of the largest catalogue of spectroscopically confirmed x-ray galaxy clusters

Kirkpatrick

Monthly Notices of the Royal Astronomical Society

Finoguenov

et al. 2021

Self Cite

“…Data Run 16 contains 2740 clusters with close to 42 000 galaxies with spectroscopic redshifts. There are a number of parameters measured for each cluster, including the virial mass M 200 estimated from its velocity dispersion, and both M 200 and the X-ray luminosity L X are iteratively calibrated using an M 200 − L X scaling relation (Capasso et al 2020). Also provided within SPIDERS are three potential definitions of the centre of a cluster, each of which has been used for an independent measurement ofˆ .…”

Section: Spiders Cataloguementioning

confidence: 99%

Gravitational redshifting of galaxies in the SPIDERS cluster catalogue

Mpetha

Collins

Monthly Notices of the Royal Astronomical Society

et al. 2021

Self Cite

Data from the SPectroscopic IDentification of ERosita Sources (SPIDERS) are searched for a detection of the gravitational redshifting of light from ∼20 000 galaxies in ∼2500 galaxy clusters using three definitions of the cluster centre: its Brightest Cluster Galaxy (BCG), the redMaPPer identified Central Galaxy (CG), or the peak of X-ray emission. Distributions of velocity offsets between galaxies and their host cluster’s centre, found using observed redshifts, are created. The quantity $\hat{\Delta }$, the average of the radial velocity difference between the cluster members and the cluster systemic velocity, reveals information on the size of a combination of effects on the observed redshift, dominated by gravitational redshifting. The change of $\hat{\Delta }$ with radial distance is predicted for SPIDERS galaxies in General Relativity (GR), and f(R) gravity, and compared to the observations. The values of $\hat{\Delta }=-13.5\pm 4.7$ km s−1, $\hat{\Delta }=-12.5\pm 5.1$ km s−1, and $\hat{\Delta }=-18.6\pm 4.8$ km s−1 for the BCG, X-ray and CG cases respectively broadly agree with the literature. There is no significant preference of one gravity theory over another, but all cases give a clear detection (>2.5σ) of $\hat{\Delta }$. The BCG centroid is deemed to be the most robust method in this analysis, due to no well defined central redshift when using an X-ray centroid, and CGs identified by redMaPPer with no associated spectroscopic redshift. For future gravitational redshift studies, an order of magnitude more galaxies, ∼500 000, will be required-a possible feat with the forthcoming Vera C. Rubin Observatory, Euclid and eROSITA.

CODEX clusters

Finoguenov

Rykoff

et al. 2020

A&A

Self Cite

Context. Large area catalogs of galaxy clusters constructed from ROSAT All-Sky Survey provide the basis for our knowledge of the population of clusters thanks to long-term multiwavelength efforts to follow up observations of these clusters. Aims. The advent of large area photometric surveys superseding previous, in-depth all-sky data allows us to revisit the construction of X-ray cluster catalogs, extending the study to lower cluster masses and higher redshifts and providing modeling of the selection function. Methods. We performed a wavelet detection of X-ray sources and made extensive simulations of the detection of clusters in the RASS data. We assigned an optical richness to each of the 24 788 detected X-ray sources in the 10 382 square degrees of the Baryon Oscillation Spectroscopic Survey area using red sequence cluster finder redMaPPer version 5.2 run on Sloan Digital Sky Survey photometry. We named this survey COnstrain Dark Energy with X-ray (CODEX) clusters. Results. We show that there is no obvious separation of sources on galaxy clusters and active galactic nuclei (AGN) based on the distribution of systems on their richness. This is a combination of an increasing number of galaxy groups and their selection via the identification of X-ray sources either by chance or by groups hosting an AGN. To clean the sample, we use a cut on the optical richness at the level corresponding to the 10% completeness of the survey and include it in the modeling of the cluster selection function. We present the X-ray catalog extending to a redshift of 0.6. Conclusions. The CODEX suvey is the first large area X-ray selected catalog of northern clusters reaching fluxes of 10−13 ergs s−1 cm−2. We provide modeling of the sample selection and discuss the redshift evolution of the high end of the X-ray luminosity function (XLF). Our results on z < 0.3 XLF agree with previous studies, while we provide new constraints on the 0.3 < z < 0.6 XLF. We find a lack of strong redshift evolution of the XLF, provide exact modeling of the effect of low number statistics and AGN contamination, and present the resulting constraints on the flat ΛCDM.