Improving the Determination of Supernova Cosmological Redshifts by Using Galaxy Groups

Fuente: arXiv
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Auteurs principaux: Peterson, Erik R., Carreres, Bastien, Carr, Anthony, Scolnic, Daniel, Bailey, Ava, Davis, Tamara M., Brout, Dillon, Howlett, Cullan, Jones, David O., Riess, Adam G., Said, Khaled, Taylor, Georgie
Format: Preprint
Publié: 2024
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author Peterson, Erik R.
Carreres, Bastien
Carr, Anthony
Scolnic, Daniel
Bailey, Ava
Davis, Tamara M.
Brout, Dillon
Howlett, Cullan
Jones, David O.
Riess, Adam G.
Said, Khaled
Taylor, Georgie
author_facet Peterson, Erik R.
Carreres, Bastien
Carr, Anthony
Scolnic, Daniel
Bailey, Ava
Davis, Tamara M.
Brout, Dillon
Howlett, Cullan
Jones, David O.
Riess, Adam G.
Said, Khaled
Taylor, Georgie
contents At the low-redshift end ($z<0.05$) of the Hubble diagram with Type Ia Supernovae (SNe Ia), the contribution to Hubble residual scatter from peculiar velocities is of similar size to that due to the limitations of the standardization of the SN Ia light curves. A way to improve the redshift measurement of the SN host galaxy is to utilize the average redshift of the galaxy group, effectively averaging over small-scale/intracluster peculiar velocities. One limiting factor is the fraction of SN host galaxies in galaxy groups, previously found to be 30% using (relatively incomplete) magnitude-limited galaxy catalogs. Here, we do the first analysis of N-body simulations to predict this fraction, finding $\sim$73% should have associated groups and group averaging should improve redshift precision by $\sim$135 km s$^{-1}$ ($\sim$0.04 mag at $z=0.025$). Furthermore, using spectroscopic data from the Anglo-Australian Telescope, we present results from the first pilot program to evaluate whether or not 23 previously unassociated SN Ia hosts belong in groups. We find that 91% of these candidates can be associated with groups, consistent with predictions from simulations given the sample size. Combining with previously assigned SN host galaxies in Pantheon+, we demonstrate improvement in Hubble residual scatter equivalent to 145 km s$^{-1}$, also consistent with simulations. For new and upcoming low-$z$ samples from, for example, ZTF and LSST, a separate follow-up program identifying galaxy groups of SN hosts is a highly cost-effective way to enhance their constraining power.
format Preprint
id arxiv_https___arxiv_org_abs_2408_14560
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Improving the Determination of Supernova Cosmological Redshifts by Using Galaxy Groups
Peterson, Erik R.
Carreres, Bastien
Carr, Anthony
Scolnic, Daniel
Bailey, Ava
Davis, Tamara M.
Brout, Dillon
Howlett, Cullan
Jones, David O.
Riess, Adam G.
Said, Khaled
Taylor, Georgie
Cosmology and Nongalactic Astrophysics
At the low-redshift end ($z<0.05$) of the Hubble diagram with Type Ia Supernovae (SNe Ia), the contribution to Hubble residual scatter from peculiar velocities is of similar size to that due to the limitations of the standardization of the SN Ia light curves. A way to improve the redshift measurement of the SN host galaxy is to utilize the average redshift of the galaxy group, effectively averaging over small-scale/intracluster peculiar velocities. One limiting factor is the fraction of SN host galaxies in galaxy groups, previously found to be 30% using (relatively incomplete) magnitude-limited galaxy catalogs. Here, we do the first analysis of N-body simulations to predict this fraction, finding $\sim$73% should have associated groups and group averaging should improve redshift precision by $\sim$135 km s$^{-1}$ ($\sim$0.04 mag at $z=0.025$). Furthermore, using spectroscopic data from the Anglo-Australian Telescope, we present results from the first pilot program to evaluate whether or not 23 previously unassociated SN Ia hosts belong in groups. We find that 91% of these candidates can be associated with groups, consistent with predictions from simulations given the sample size. Combining with previously assigned SN host galaxies in Pantheon+, we demonstrate improvement in Hubble residual scatter equivalent to 145 km s$^{-1}$, also consistent with simulations. For new and upcoming low-$z$ samples from, for example, ZTF and LSST, a separate follow-up program identifying galaxy groups of SN hosts is a highly cost-effective way to enhance their constraining power.
title Improving the Determination of Supernova Cosmological Redshifts by Using Galaxy Groups
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2408.14560