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Ciotti, Luca; Giampieri, G.

doi:10.1023/a:1008276022759

Cited by 12 publications

(11 citation statements)

References 13 publications

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“…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). Its detection based on SDSS data has been reported by Pereira & Kuhn (2005), Agustsson &Brainerd (2006), andFaltenbacher et al (2007), while non-detections of this alignment are also reported based on data from both the 2dF Galaxy Redshift Survey (2dFGRS; Colless et al 2001;Bernstein & Norberg 2002) and SDSS (Siverd et al 2009).…”

Section: Introductionmentioning

confidence: 80%

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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Section: Introductionmentioning

confidence: 80%

Intrinsic Alignment of Cluster Galaxies: The Redshift Evolution

Hao

Kubo

Feldmann

et al. 2011

ApJ

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“…It is commonly believed that tidal torques are responsible for this radial alignment (e.g. Ciotti & Dutta 1994; Ciotti & Giampieri 1998; Pereira et al 2008), as tidal forces on these relatively small scales (≲1 Mpc ) are sufficiently strong to affect halo shapes on short time‐scales.…”

Section: Introductionmentioning

confidence: 99%

The large-scale orientations of disc galaxies

Hahn

Teyssier

Carollo

2010

Monthly Notices of the Royal Astronomical Society

135

160

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We use a 380‐h−1 pc resolution hydrodynamic adaptive mesh refinement (AMR) simulation of a cosmic filament to investigate the orientations of a sample of ∼100 well‐resolved galactic discs spanning two orders of magnitude in both stellar and halo mass. We find: (i) at z= 0, there is an almost perfect alignment at a median angle of 18°, in the inner dark matter halo regions where the discs reside, between the spin vector of the gaseous and stellar galactic discs and that of their inner host haloes. The alignment between galaxy spin and spin of the entire host halo is however significantly weaker, ranging from a median of ∼ 46° at z= 1 to ∼ 50° at z= 0. (ii) The most massive galaxy discs have spins preferentially aligned so as to point along their host filaments. (iii) The spin of discs in lower mass haloes shows, at redshifts above z∼ 0.5 and in regions of low environmental density, a clear signature of alignment with the intermediate principal axis of the large‐scale tidal field. This behaviour is consistent with predictions of linear tidal torque theory. This alignment decreases with increasing environmental density, and vanishes in the highest density regions. Non‐linear effects in the high‐density environments are plausibly responsible for establishing this density‐alignment correlation. We expect that our numerical results provide important insights for both understanding intrinsic alignment in weak lensing from the astrophysical perspective and formation and evolution processes of galactic discs in a cosmological context.

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“…In particular, we consider the (rigid) oscillations of elliptical galaxies (a similar analysis has been carried out in Ciotti & Giampieri 1997) and the precession of spiral galaxies. We show below that internal dynamics is much faster than rigidbody dynamics, thus confirming the results of Ciotti & Dutta (1994) for elliptical galaxies.…”

Section: Appendix A: Rigid-body Approximationmentioning

confidence: 99%

On the origin of intrinsic alignment in cosmic shear measurements: an analytic argument

Camelio

Lombardi

2015

A&A

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Galaxy intrinsic alignment can be a severe source of error in weak-lensing studies. The problem has been widely studied by numerical simulations and with heuristic models, but without a clear theoretical justification of its origin and amplitude. In particular, it is still unclear whether intrinsic alignment of galaxies is dominated by formation and accretion processes or by the effects of the instantaneous tidal field acting upon them. We investigate this question by developing a simple model of intrinsic alignment for elliptical galaxies, based on the instantaneous tidal field. Making use of the galaxy stellar distribution function, we estimate the intrinsic alignment signal and find that although it has the expected dependence on the tidal field, it is too weak to account for the observed signal. This is an indirect validation of the standard view that intrinsic alignment is caused by formation and/or accretion processes.

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Untitled

Cited by 12 publications

References 13 publications

Intrinsic Alignment of Cluster Galaxies: The Redshift Evolution

Intrinsic Alignment of Cluster Galaxies: The Redshift Evolution

The large-scale orientations of disc galaxies

On the origin of intrinsic alignment in cosmic shear measurements: an analytic argument

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