J/A+A/668/A34 Solar dipole from supernovae Ia (Horstmann+, 2022)
Inference of the cosmic rest-frame from supernovae Ia.
Horstmann N., Pietschke Y., Schwarz D.J.
<Astron. Astrophys. 668, A34 (2022)>
=2022A&A...668A..34H 2022A&A...668A..34H (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Redshifts ; Optical
Keywords: cosmological parameters - cosmology: observations -
large-scale structure of Universe
Abstract:
We determine the proper motion of the Solar system from the Pantheon
sample of supernovae (SNe) of type Ia. The posterior distribution of
the Solar system proper velocity, its direction and relevant
cosmological parameters are obtained based on the observed distance
moduli, heliocentric redshifts, and positions of SNe by means of a
Markov Chain Monte Carlo method. We account for the unknown peculiar
motion of SNe by including their expected covariance from linear
theory. We find that the Solar system moves with vo=249±51km/s
towards RA=166±16deg, Dec=10±19deg (J2000) (all at 68% C.L.). The
direction of motion agrees with the direction of the dipole observed
in the cosmic microwave background (CMB) (RA=166deg, Dec=-7deg). The
inferred velocity is 2.4σ smaller than the value inferred from a
purely kinematic interpretation of the CMB dipole (370km/s). Assuming
a flat Λ cold dark matter model, we find no degeneracy of Solar
proper motion with other cosmological parameters. The dimensionless
matter density, ΩM=0.305±0.022, is in excellent agreement
with CMB measurements. We also find no degeneracy of the Solar proper
motion with the SN calibration nuisance parameter. Bulk flows might be
able to explain why the solar motion appears to be slower w.r.t.
nearby SNe. We conclude that a larger sample of SNe, distributed over
wide areas of sky and a broad range in redshift, will allow an
independent and robust test of the kinematic nature of the CMB dipole.
Description:
SN data from the Pantheon catalogue (Scolnic et al.,
2018ApJ...859..101S 2018ApJ...859..101S, Cat. J/ApJ/859/101) and covariances as used in
Horstmann et al. (2021arXiv211103055H 2021arXiv211103055H).
The SN catalogue is from Steinhardt et al. (2020ApJ...902...14S 2020ApJ...902...14S, Cat.
J/ApJ/902/14) with some corrected positions, as described in Horstmann
et al. (2021arXiv211103055H 2021arXiv211103055H). The peculiar velocities are calculated
using the online tool published in conjunction with Carrick et al.
(2015MNRAS.450..317C 2015MNRAS.450..317C).
The covariance matrix accounts for correlations in the observed
magnitudes due to correlated peculiar velocities
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
sn_data.dat 111 1048 SN position, distance modulus and redshift
(mostly from Steinhardt et al.,
2020ApJ...902...14S 2020ApJ...902...14S, Cat. J/ApJ/902/14)
list.dat 93 1 *Information on covariance matrix
fits/* . 1 Velocity covariance, 'V' in Horstmann et al.,
2021arXiv211103055H 2021arXiv211103055H
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Note on list.dat: 1048x1048 covariance matrix in F17.14 format.
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See also:
J/ApJ/859/101 : The supernovae Ia Pantheon sample (Scolnic+, 2018)
J/ApJ/902/14 : Revised redshifts of Pantheon supernovae Ia (Steinhardt+, 2020)
Byte-by-byte Description of file: sn_data.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name SN object identifier
12- 18 A7 --- Survey Survey
20- 30 F11.8 --- mu Distance modulus
32- 44 F13.11 --- e_mu Distance modulus uncertainty
46- 58 F13.11 --- zhel Heliocentric redshift
60- 73 F14.10 deg RAdeg Right ascension (J2000)
75- 90 F16.12 deg DEdeg Declination (J2000)
92-105 F14.11 c vE ?=0 Peculiar velocity for local SNe (from
Carrick et al., 2015MNRAS.450..317C 2015MNRAS.450..317C)
in units of speed of light
107-111 A5 --- hostZ [True False] True if redshift measured in host
galaxy according to Steinhardt et al.
(2020ApJ...902...14S 2020ApJ...902...14S, Cat. J/ApJ/902/14),
False otherwise
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Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Nx Number of pixels along X-axis
6- 9 I4 --- Ny Number of pixels along Y-axis
11- 14 I4 Kibyte size Size of FITS file
16- 27 A12 --- FileName Name of FITS file, in subdirectory fits
29- 93 A65 --- Title Title of the FITS file
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Acknowledgements:
Nick Horstmann, nhorstmann(at)physik.uni-bielefeld.de
References:
Scolnic et al. 2018ApJ...859..101S 2018ApJ...859..101S
The Complete Light-curve Sample of Spectroscopically Confirmed SNe Ia from
Pan-STARRS1 and Cosmological Constraints from the Combined Pantheon Sample
Horstmann, Pietschke, Schwarz, 2021arXiv211103055H 2021arXiv211103055H
Inference of the cosmic rest-frame from supernovae Ia
Steinhardt, Sneppen, Bidisha, 2020ApJ...902...14S 2020ApJ...902...14S
Effects of Supernova Redshift Uncertainties on the Determination of
Cosmological Parameters
Carrick et al., 2015MNRAS.450..317C 2015MNRAS.450..317C
Cosmological parameters from the comparison of peculiar velocities with
predictions from the 2M++ density field
(End) N. Horstmann [Bielefeld Univ., Germany], P. Vannier [CDS] 09-Nov-2022