ZTF SN Ia DR2: Cosmology-independent constraints on Type Ia supernova standardisation from supernova siblings

Open Access

Table 2.

Mean α and β along with the dispersion in both parameters for the complete, spectroscopic only, and photo-spec sample.

Sample	α	β	σ(α)	σ(β)	σ_int (mag)	N_pairs^(a)
All	0.218 ± 0.055	3.08 ± 0.31	< 0.195	< 0.92	< 0.103	25
Spec	0.217 ± 0.061	3.08 ± 0.74	< 0.215	< 2.70	< 0.137	12
Phot-Spec	0.186 ± 0.091	3.03 ± 0.50	< 0.364	< 1.77	< 0.165	13
Single α, β
All	0.228 ± 0.030	3.16 ± 0.19	…	…	< 0.088	25
Spec	0.226 ± 0.038	3.35 ± 0.35	…	…	< 0.119	12
Phot-Spec	0.235 ± 0.069	3.08 ± 0.28	…	…	< 0.177	13
Low-mass	0.118 ± 0.078	3.16 ± 0.15	…	…		8
High-mass	0.238 ± 0.028	2.97 ± 0.40	…	…		17
Split x₁
All	0.274 ± 0.045/0.134 ± 0.072	3.16 ± 0.19	…	…	< 0.097	25

Notes. We report the values for the cases with a free σ(α) and σ(β) as well as the cases with a fixed σ(α) = σ(β) = 0. We also report the case with a split for α constraints based on the x₁ value. The two α values are for the low and high x₁ SNe Ia, respectively (see text for more details).

^(a)

We clarify here that the limit on the σ_int from the combined sample is smaller due to the larger number of objects compared to either of the individual spec and phot-spec subsamples.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.