Modeling the local velocity field with SNIa Virtual Observatory Resource

Authors
  1. Weyant A.
  2. Wood-Vasey M.
  3. Wasserman L.
  4. Freeman P.
  5. Published by
    CDS
Abstract

We apply statistically rigorous methods of nonparametric risk estimation to the problem of inferring the local peculiar velocity field from nearby Type Ia supernovae (SNIa). We use two nonparametric methods -weighted least squares (WLS) and coefficient unbiased (CU)- both of which employ spherical harmonics to model the field and use the estimated risk to determine at which multipole to truncate the series. We show that if the data are not drawn from a uniform distribution or if there is power beyond the maximum multipole in the regression, a bias is introduced on the coefficients using WLS. CU estimates the coefficients without this bias by including the sampling density making the coefficients more accurate but not necessarily modeling the velocity field more accurately. After applying nonparametric risk estimation to SNIa data, we find that there are not enough data at this time to measure power beyond the dipole. The WLS Local Group bulk flow is moving at 538+/-86km/s toward (l,b)=(258+/-10{deg},36+/-11{deg}) and the CU bulk flow is moving at 446+/-101km/s toward (l,b)=(273+/-11{deg},46+/-8{deg}). We find that the magnitude and direction of these measurements are in agreement with each other and previous results in the literature.

Keywords
  1. supernovae
  2. redshifted
  3. astronomical-models
Bibliographic source Bibcode
2011ApJ...732...65W
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/732/65
IVOA Identifier IVOID
ivo://CDS.VizieR/J/ApJ/732/65
Document Object Identifer DOI
doi:10.26093/cds/vizier.17320065

Access

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http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/732/65
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/732/65
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/732/65
IVOA Table Access TAP
http://tapvizier.cds.unistra.fr/TAPVizieR/tap
Run SQL-like queries with TAP-enabled clients (e.g., TOPCAT).
IVOA Cone Search SCS
For use with a cone search client (e.g., TOPCAT).
https://vizier.cds.unistra.fr/viz-bin/conesearch/0?
https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/732/65/table1?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/732/65/table1?

History

2012-12-04T15:05:00Z
Resource record created
2012-12-04T15:05:00Z
Created
2018-01-04T08:22:19Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr