Anisotropic Distribution of SDSS Satellite Galaxies: Planar (Not Polar) Alignment

Brainerd, Tereasa G.

doi:10.1086/432713

Cited by 156 publications

(228 citation statements)

References 35 publications

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“…Although the alignments between the host shapes and the satellite locations have been supported by several observational studies (e.g., Brainerd 2005;Yang et al 2006;Azzaro et al 2007;Bailin et al 2008;Agustsson & Brainerd 2010, no direct observational evidence was found for the preferential alignments of the satellite infall directions with the minor principal axes of the velocity shears, nor for the strong crosscorrelations between the velocity shear field smoothed on different scales. Very recently, Lee et al (2014) have found observational evidence for the alignments between the infall directions of the satellite galaxies and the minor principal axes of the local velocity shear tensors.…”

Section: Introductionmentioning

confidence: 88%

Detection of the Velocity Shear Effect on the Spatial Distributions of the Galactic Satellites in Isolated Systems

Lee¹,

Choi²

2015

ApJ

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We report a detection of the effect of the large-scale velocity shear on the spatial distributions of the galactic satellites around the isolated hosts. Identifying the isolated galactic systems, each of which consists of a single host galaxy and its satellites, from the Seventh Data Release of the Sloan Digital Sky Survey and reconstructing linearly the velocity shear field in the local universe, we measure the alignments between the relative positions of the satellites from their isolated hosts and the principal axes of the local velocity shear tensors projected onto the plane of sky. We find a clear signal that the galactic satellites in isolated systems are located preferentially along the directions of the minor principal axes of the large-scale velocity shear field. Those galactic satellites that are spirals, are brighter, are located at distances larger than the projected virial radii of the hosts, and belong to the spiral hosts yield stronger alignment signals, which implies that the alignment strength depends on the formation and accretion epochs of the galactic satellites. It is also shown that the alignment strength is quite insensitive to the cosmic web environment, as well as the size and luminosity of the isolated hosts. Although this result is consistent with the numerical finding of Libeskind et al. based on an N-body experiment, owing to the very low significance of the observed signals, it remains inconclusive whether or not the velocity shear effect on the satellite distribution is truly universal.

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Section: Introductionmentioning

confidence: 88%

Detection of the Velocity Shear Effect on the Spatial Distributions of the Galactic Satellites in Isolated Systems

Lee¹,

Choi²

2015

ApJ

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“…It is argued, based on simulations, that the preferred accretion direction of satellite halos toward the host halo along the filaments is largely responsible for the BCG alignment (Tormen 1997;Vitvitska et al 2002;Knebe et al 2004;Zentner et al 2005;Wang et al 2005). The detection of this alignment from real data has been reported by many teams (Sastry 1968;Austin & Peach 1974;Dressler 1978;Carter & Metcalfe 1980;Binggeli 1982;Brainerd 2005;Yang et al 2006;Azzaro et al 2007;Wang et al 2008;Siverd et al 2009;Niederste-Ostholt et al 2010), though non-detections of this alignment were also reported (Tucker & Peterson 1988;Ulmer et al 1989). For the satellite alignment, tidal torque is thought to play a major role in its formation (Ciotti & Dutta 1994;Ciotti & Giampieri 1998;Kuhlen et al 2007;Pereira et al 2008;Faltenbacher et al 2008;Pereira & Bryan 2010).…”

Section: Introductionmentioning

confidence: 96%

Intrinsic Alignment of Cluster Galaxies: The Redshift Evolution

Hao

Kubo

Feldmann

et al. 2011

ApJ

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We present measurements of two types of cluster galaxy alignments based on a volume limited and highly pure ( 90%) sample of clusters from the GMBCG catalog derived from Data Release 7 of the Sloan Digital Sky Survey (SDSS DR7). We detect a clear brightest cluster galaxy (BCG) alignment (the alignment of major axis of the BCG toward the distribution of cluster satellite galaxies). We find that the BCG alignment signal becomes stronger as the redshift and BCG absolute magnitude decrease and becomes weaker as BCG stellar mass decreases. No dependence of the BCG alignment on cluster richness is found. We can detect a statistically significant ( 3σ ) satellite alignment (the alignment of the major axes of the cluster satellite galaxies toward the BCG) only when we use the isophotal fit position angles (P.A.s), and the satellite alignment depends on the apparent magnitudes rather than the absolute magnitudes of the BCGs. This suggests that the detected satellite alignment based on isophotal P.A.s from the SDSS pipeline is possibly due to the contamination from the diffuse light of nearby BCGs. We caution that this should not be simply interpreted as non-existence of the satellite alignment, but rather that we cannot detect them with our current photometric SDSS data. We perform our measurements on both SDSS r-band and i-band data, but do not observe a passband dependence of the alignments.

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“…In particular, recent studies of galaxies in the Sloan Digital Sky Survey (SDSS; York et al 2000) have revealed that satellite galaxies are preferentially distributed along the major axis of the central galaxies (Brainerd 2005;Yang et al 2006;Azzaro et al 2007;Faltenbacher et al 2007Faltenbacher et al , 2009) and tend to be preferentially oriented toward the central galaxy (Pereira & Kuhn 2005;Agustsson & Brainerd 2006;Faltenbacher et al 2007). These studies were mostly limited to the local universe and intermediate-to-small scales (less than a few tens of Mpc).…”

Section: Introductionmentioning

confidence: 99%

THE DETECTION OF THE LARGE-SCALE ALIGNMENT OF MASSIVE GALAXIES AT z ∼ 0.6

Jing

Faltenbacher

et al. 2013

ApJ

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We report on the detection of the alignment between galaxies and large-scale structure at z ∼ 0.6 based on the CMASS galaxy sample from the Baryon Oscillation Spectroscopy Survey Data Release 9. We use two statistics to quantify the alignment signal: (1) the alignment two-point correlation function that probes the dependence of galaxy clustering at a given separation in redshift space on the projected angle (θ p ) between the orientation of galaxies and the line connecting to other galaxies, and (2) the cos(2θ )-statistic that estimates the average of cos(2θ p ) for all correlated pairs at a given separation s. We find a significant alignment signal out to about 70 h −1 Mpc in both statistics. Applications of the same statistics to dark matter halos of mass above 10 12 h −1 M in a large cosmological simulation show scale-dependent alignment signals similar to the observation, but with higher amplitudes at all scales probed. We show that this discrepancy may be partially explained by a misalignment angle between central galaxies and their host halos, though detailed modeling is needed in order to better understand the link between the orientations of galaxies and host halos. In addition, we find systematic trends of the alignment statistics with the stellar mass of the CMASS galaxies, in the sense that more massive galaxies are more strongly aligned with the large-scale structure.

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Anisotropic Distribution of SDSS Satellite Galaxies: Planar (Not Polar) Alignment

Cited by 156 publications

References 35 publications

Detection of the Velocity Shear Effect on the Spatial Distributions of the Galactic Satellites in Isolated Systems

Detection of the Velocity Shear Effect on the Spatial Distributions of the Galactic Satellites in Isolated Systems

Intrinsic Alignment of Cluster Galaxies: The Redshift Evolution

THE DETECTION OF THE LARGE-SCALE ALIGNMENT OF MASSIVE GALAXIES AT z ∼ 0.6

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