Journal
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume 433, Issue 4, Pages 2727-2738Publisher
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stt855
Keywords
galaxies: clusters: general; galaxies: formation; galaxies: statistics
Categories
Funding
- ERC StG grant [DEGAS-259586]
- US Department of Energy by Lawrence Livermore National Laboratory [DE-AC52-07NA27344]
- STFC (UK)
- Astrophysical Research Consortium (ARC
- Australia)
- AAO
- Alfred P. Sloan Foundation
- National Science Foundation
- U.S. Department of Energy
- National Aeronautics and Space Administration
- Japanese Monbukagakusho
- Max Planck Society
- Higher Education Funding Council for England
- American Museum of Natural History
- Astrophysical Institute Potsdam
- University of Basel
- University of Cambridge
- Case Western Reserve University
- University of Chicago
- Drexel University
- Fermilab
- Institute for Advanced Study
- Johns Hopkins University
- Joint Institute for Nuclear Astrophysics
- Kavli Institute for Particle Astrophysics and Cosmology
- Chinese Academy of Sciences (LAMOST)
- Los Alamos National Laboratory
- Max-Planck-Institute for Astronomy (MPIA)
- Max-Planck-Institute for Astrophysics (MPA)
- New Mexico State University
- Ohio State University
- University of Pittsburgh
- University of Portsmouth
- Princeton University
- United States Naval Observatory
- University of Washington
- STFC [ST/I000976/1, ST/H004548/1, ST/I00162X/1, ST/I001166/1, ST/G001987/1, ST/J002291/1, ST/K003577/1] Funding Source: UKRI
- Science and Technology Facilities Council [ST/H004548/1, ST/I001166/1, ST/G001987/1, ST/I000976/1, ST/I003088/1, ST/I00162X/1, ST/H00131X/1, ST/K003577/1, ST/H008578/1, ST/J002291/1] Funding Source: researchfish
Ask authors/readers for more resources
We constrain the distributions of projected radial alignment angles of satellite galaxy shapes within the Galaxy And Mass Assembly survey group catalogue. We identify the galaxy groups using spectroscopic redshifts and measure galaxy projected ellipticities from Sloan Digital Sky Survey imaging. With a sample of 3850 groups with 13 655 satellite galaxies with high quality shape measurements, we find a less than 2 Sigma signal of radial alignments in the mean projected ellipticity components and the projected position angle when using galaxy shape estimates optimized for weak lensing measurements. Our radial alignment measurement increases to greater than 3 Sigma significance relative to the expectation for no alignments if we use 2D Sersic model fits to define galaxy orientations. Our weak measurement of radial alignments is in conflict with predictions from dark-matter N-body simulations, which we interpret as evidence for large misalignments of baryons and dark matter in group and cluster satellites. Within our uncertainties, that are dominated by our small sample size, we find only weak and marginally significant trends of the radial alignment angle distributions on projected distance from the group centre, host halo mass, and redshift that could be consistent with a tidal torquing mechanism for radial alignments. Using our lensing optimized shape estimators, we estimate that intrinsic alignments of galaxy group members may contribute a systematic error to the mean differential projected surface mass density of groups inferred from weak lensing observations by -1 +/- 20 per cent at scales around 300 h(-1) kpc from the group centre assuming a photometric redshift rms error of 10 per cent, and given our group sample with median redshift of 0.17 and median virial masses similar to 10(13) h(-1) M-circle dot.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available