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Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova samples
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2014 (Engelska)Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 568, s. A22-Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Aims. We present cosmological constraints from a joint analysis of type la supernova (SN Ia) observations obtained by the SDSS-II and SNLS collaborations. The dataset includes several low-redshift samples (z < 0.1), all three seasons from the SDSS-11 (0.05 < z < 0.4), and three years from SNLS (0.2 < z < 1), and it totals 740 spectroscopically confirmed type la supernovae with high quality light curves. Methods. We followed the methods and assumptions of the SNLS three-year data analysis except for the following important improvements: I) the addition of the full SDSS-II spectroscopically-confirmed SN la sample in both the training of the SALT2 light-curve model and in the Hubble diagram analysis (374 SNe); 2) intercalibration of the SNLS and SDSS surveys and reduced systematic uncertainties in the photometric calibration, performed blindly with respect to the cosmology analysis; and 3) a thorough investigation of systematic errors associated with the SALT2 modeling of SN la light curves. Results. We produce recalibrated SN la light curves and associated distances for the SDSS-II and SNLS samples. The large SOSS-II sample provides an effective, independent, low -z anchor for the Hubble diagram and reduces the systematic error from calibration systematics in the low -z SN sample. For a flat ACDM cosmology, we find Omega(m), = 0.295 0.034 (stat+sys), a value consistent with the most recent cosmic microwave background (CMB) measurement from the Planck and WMAP experiments. Our result is 1.8 sigma (stat+sys) different than the previously published result of SNLS three-year data. The change is due primarily to improvements in the SNLS photometric calibration. When combined with CMB constraints, we measure a constant dark energy equation of state parameter omega = -1.018 +/- 0,057 (sral+sys) for a fiat universe. Adding baryon acoustic oscillation distance measurements gives similar constraints: omega = 59 -1.027 0.055. Our supernova measurements provide the most stringent constraints to date on the nature of dark energy.

Ort, förlag, år, upplaga, sidor
2014. Vol. 568, s. A22-
Nyckelord [en]
cosmology: observations, distance scale dark energy
Nationell ämneskategori
Astronomi, astrofysik och kosmologi
Identifikatorer
URN: urn:nbn:se:su:diva-108382DOI: 10.1051/0004-6361/201423413ISI: 000341185900037Scopus ID: 2-s2.0-84905723106OAI: oai:DiVA.org:su-108382DiVA, id: diva2:757820
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AuthorCount:63;

Tillgänglig från: 2014-10-23 Skapad: 2014-10-22 Senast uppdaterad: 2022-10-12Bibliografiskt granskad

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Goobar, ArielSollerman, Jesper

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Goobar, ArielSollerman, Jesper
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FysikumOskar Klein-centrum för kosmopartikelfysik (OKC)Institutionen för astronomi
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Astronomy and Astrophysics
Astronomi, astrofysik och kosmologi

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