A NEW MEASUREMENT OF THE BULK FLOW OF X-RAY LUMINOUS CLUSTERS OF GALAXIES

By A. Kashlinsky, F. Atrio-Barandela, H. Ebeling, A. Edge, D. Kocevski. 2009

167 citations recorded by the source corpus.

We present new measurements of the large-scale bulk flows of galaxy clusters based on five-year WMAP data and a significantly expanded X-ray cluster catalog. Our method probes the flow via measurements of the kinematic Sunyaev–Zel'dovich (SZ) effect produced by the hot gas in moving clusters. It computes the dipole in the cosmic microwave background data at cluster pixels, which preserves the SZ component while integrating down other contributions. Our improved catalog of over 1000 clusters enables us to further investigate possible systematic effects and, thanks to a higher median cluster redshift, allows us to measure the bulk flow to larger scales. We present a corrected error treatment and demonstrate that the more X-ray luminous clusters, while fewer in number, have much larger optical depth, resulting in a higher dipole and thus a more accurate flow measurement. This results in the observed correlation of the dipole derived at the aperture of zero monopole with the monopole measured over the cluster central regions. This correlation is expected if the dipole is produced by the SZ effect and cannot be caused by unidentified systematics (or primary cosmic microwave background anisotropies). We measure that the flow is consistent with approximately constant velocity out to at least ≃800 Mpc. The significance of the measured signal peaks around 500 h−170 Mpc, most likely because the contribution from more distant clusters becomes progressively more diluted by the WMAP beam. However, at present, we cannot rule out that these more distant clusters simply contribute less to the overall motion.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/b127229b2adaa453945e918ef8dff0376037ce55

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Citations in the corpus

Probing the anisotropic local Universe and beyond with SNe Ia data (2010, methodology): “…the discrepancy between the luminosity distance of Union 2 SNe Ia and the value predicted by the standard CDM model, for z < 0.06 (top panel) 2 Kashlinsky et al. (2008, 2010) have reported an even faster coherent flow out to at least ∼800 Mpc, using measurements of the kinematic Sunyaev–…”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, methodology): “On larger scales, [493] claimed the detection of a dipole anisotropy attributed to the kinetic SZ decrement in the WMAP temperature map at the position of X-ray galaxy clusters.”
Cosmic flows on 100 h−1 Mpc scales: standardized minimum variance bulk flow, shear and octupole moments (2009, background): “Recently, Kashlinsky et al. (2008, 2010) and Atrio-Barandela et al. (2010) claimed to have detected a dipole in filtered WMAP CMB temperature maps measured at the locations of rich clusters.”
The current status of galaxy formation (2012, methodology): “Bulk flows are found over 100 Mpc scales that are about two standard deviations larger than expected in ΛCDM (Feldman et al., 2010).”
Cosmic flows in the nearby universe from Type Ia supernovae (2011, background): “However, amplitude of the Kashlinsky et al. (2010) bulk flow is systematically uncertain.”
A structure in the early Universe at z ∼ 1.3 that exceeds the homogeneity scale of the R-W concordance cosmology (2012, background): “Similarly, the existence of cosmic flows on approximately Gpc-scales (e.g. Kashlinsky et al. 2010), regardless of their cause, is itself implying that the universe is not homogeneous.”
The 2M++ galaxy redshift catalogue (2011, background): “Recently, several intriguing measurements (Kashlinsky et al. 2008; Watkins et al. 2009; Lavaux et al. 2010; Kashlinsky et al. 2010; Feldman et al. 2010) of the mean or “bulk” flow on scales larger than 100h−1 Mpc suggest a high velocity of our local ∼ 100 h−1 Mpc volume with respect to the Cosmic…”
Cosmological Parameters from Observations of Galaxy Clusters (2011, result): “Although some initial results based on such measurements have been reported (e.g. Kashlinsky et al. 2008, 2010; Keisler 2009; Osborne et al. 2010), the technique has not yet reached the maturity of those discussed above and is not discussed further in this review.”
Evidence for anisotropy of cosmic acceleration (2018, background): “There have been persistent claims of a “dark flow” extending out to several hundreds of megaparsec (Kashlinsky et al. 2009, 2010, 2011), although this is still under debate.”
Probing cosmic isotropy with a new X-ray galaxy cluster sample through the LX–T scaling relation (2020, background): “…Tiwari & Nusser 2016; Bengaly et al. 2018, 2019; Colin et al. 2019), gamma-ray bursts (Řípa & Shafieloo 2017; Andrade et al. 2019), peculiar velocities of galaxy clusters (Kashlinsky et al. 2008, 2010, 2011; Watkins et al. 2009; Atrio-Barandela et al. 2015) and of SNIa (Appleby et al. 2015) etc.”