Publikationsdatum:
2016-06-24
Beschreibung:
We have assembled a data set of 165 low redshift, z 〈 0.06, publicly available Type Ia supernovae (SNe Ia). We produce maximum light magnitude ( M B and M V ) distributions of SNe Ia to explore the diversity of parameter space that they can fill. Before correction for host galaxy extinction we find that the mean M B and M V of SNe Ia are –18.58 ± 0.07 and –18.72 ± 0.05 mag, respectively. Host galaxy extinction is corrected using a new method based on the SN spectrum. After correction, the mean values of M B and M V of SNe Ia are –19.10 ± 0.06 and –19.10 ± 0.05 mag, respectively. After correction for host galaxy extinction, ‘normal’ SNe Ia ( m 15 ( B ) 〈 1.6 mag) fill a larger parameter space in the width–luminosity relation than previously suggested, and there is evidence for luminous SNe Ia with large m 15 ( B ). We find a bimodal distribution in m 15 ( B ), with a pronounced lack of transitional events at m 15 ( B ) = 1.6 mag. We confirm that faster, low-luminosity SNe tend to come from passive galaxies. Dividing the sample by host galaxy type, SNe Ia from star-forming (S-F) galaxies have a mean M B = –19.20 ± 0.05 mag, while SNe Ia from passive galaxies have a mean M B = –18.57 ± 0.24 mag. Even excluding fast declining SNe, ‘normal’ ( M B 〈 –18 mag) SNe Ia from S-F and passive galaxies are distinct. In the V band, there is a difference of 0.4 ± 0.13 mag between the median ( M V ) values of the ‘normal’ SN Ia population from passive and S-F galaxies. This is consistent with (~15 ± 10) per cent of ‘normal’ SNe Ia from S-F galaxies coming from an old stellar population.
Print ISSN:
0035-8711
Digitale ISSN:
1365-2966
Thema:
Physik
