High-accuracy redshift measurements for galaxy clusters at z &lt; 0.45 based on SDSS-III photometry

Meshcheryakov, A. V.; Glazkova, V. V.; Gerasimov, S. V.; Burenin, R.; Хорунжев, Г. А.

doi:10.1134/s1063773715070038

Cited by 9 publications

(1 citation statement)

References 43 publications

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“…Machine learning methods allow to measure photometric redshifts (photo-z ) of galaxy clusters from the accurate photometric redshift estimates for individual cluster galaxies. For example, the accuracy of σ ∼ 1% was obtained for clusters at redshifts z < 0.45 using SDSS data (Meshcheryakov et al, 2015). We have trained a galaxies photo-z model based on a quantile random forest described in Meshcheryakov et al (2018).…”

Section: Photometric Redshift Estimate Using Machine Learningmentioning

confidence: 99%

Observation of a very massive galaxy cluster at z=0.76 in SRG/eROSITA all-sky survey

Burenin,

Bikmaev,

Gilfanov

et al. 2021

Preprint

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The results of multiwavelength observations of the very massive galaxy cluster SRGe CL2305.2−2248 detected in X-rays during the first SRG/eROSITA all-sky survey are discussed. This galaxy cluster was also detected earlier in microwave band through the observations of Sunyaev-Zeldovich effect in South Pole Telescope (SPT-CL J2305−2248), and in Atacama Cosmological Telescope (ACT-CL J2305.1−2248) surveys. Spectroscopic redshift measurement, z = 0.7573, was measured at the Russian 6-m BTA telescope of the SAO RAS, in good agreement with its photometric estimates, including a very accurate one obtained using machine learning methods. In addition, deep photometric measurements were made at the Russian-Turkish 1.5-m telescope (RTT150), which allows to study cluster galaxies red sequence and projected galaxies distribution. Joint analysis of the data from X-ray and microwave observations show that this cluster can be identified as a very massive and distant one using the measurements of its X-ray flux and integral comptonization parameter only. The mass of the cluster estimated according to the eROSITA data is M500 = (9.0 ± 2.6) • 10 14 M . We show that this cluster is found among of only several dozen of the most massive clusters in the observable Universe and among of only a few the most massive clusters of galaxies at z > 0.6.

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Section: Photometric Redshift Estimate Using Machine Learningmentioning

confidence: 99%

Observation of a very massive galaxy cluster at z=0.76 in SRG/eROSITA all-sky survey

Burenin,

Bikmaev,

Gilfanov

et al. 2021

Preprint

Self Cite

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Observational capabilities of the new medium- and low-resolution spectrograph at the 1.6-m telescope of the Sayan Observatory

et al. 2016

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Catalog of candidates for quasars at 3 < z < 5.5 selected among X-Ray sources from the 3XMM-DR4 survey of the XMM-Newton observatory

et al. 2016

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We have compiled a catalog of 903 candidates for type 1 quasars at redshifts 3 < z < 5.5 selected among the X-ray sources of the serendipitous XMM -Newton survey presented in the 3XMM-DR4 catalog (the median X-ray flux is ≈5×10 −15 erg s −1 cm −2 in the 0.5-2 keV energy band) and located at high Galactic latitudes |b| > 20 • in Sloan Digital Sky Survey (SDSS ) fields with a total area of about 300 deg 2 . Photometric SDSS data as well infrared 2MASS and WISE data were used to select the objects. We selected the point sources from the photometric SDSS catalog with a magnitude error δm z < 0.2 and a color i − z < 0.6 (to first eliminate the M-type stars). For the selected sources, we have calculated the dependences χ 2 (z) for various spectral templates from the library that we compiled for these purposes using the EAZY software. Based on these data, we have rejected the objects whose spectral energy distributions are better described by the templates of stars at z = 0 and obtained a sample of quasars with photometric redshift estimates 2.75 < z phot < 5.5. The selection completeness of known quasars at z spec > 3 in the investigated fields is shown to be about 80%. The normalized median absolute deviation (∆z = |z spec − z phot |) is σ ∆z/(1+z spec ) = 0.07, while the outlier fraction is η = 9%, when ∆z/(1 + z spec ) > 0.2. The number of objects per unit area in our sample exceeds the number of quasars in the spectroscopic SDSS sample at the same redshifts approximately by a factor of 1.5. The subsequent spectroscopic testing of the redshifts of our selected candidates for quasars at 3 < z < 5.5 will allow the purity of this sample to be estimated more accurately.

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High-accuracy redshift measurements for galaxy clusters at z < 0.45 based on SDSS-III photometry

Cited by 9 publications

References 43 publications

Observation of a very massive galaxy cluster at z=0.76 in SRG/eROSITA all-sky survey

Observation of a very massive galaxy cluster at z=0.76 in SRG/eROSITA all-sky survey

Observational capabilities of the new medium- and low-resolution spectrograph at the 1.6-m telescope of the Sayan Observatory

Catalog of candidates for quasars at 3 < z < 5.5 selected among X-Ray sources from the 3XMM-DR4 survey of the XMM-Newton observatory

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