Photospheric Magnitude Diagrams for Type Ii Supernovae: A Promising Tool to Compute Distances

Abstract

We develop an empirical color-based standardization for Type II supernovae (SNe II), equivalent to the classical surface brightness method given in Wesselink. We calibrate this standardization using SNe II with host galaxy distances measured using Cepheids, and a well-constrained shock breakout epoch and extinction due to the host galaxy. We estimate the reddening with an analysis of the B −V versus V −I color-color curves, similar to that of Natali et al. With four SNe II meeting the above requirements, we build a photospheric magnitude versus color diagram (similar to an H-R diagram) with a dispersion of 0.29 mag. We also show that when using time since shock breakout instead of color as the independent variable, the same standardization gives a dispersion of 0.09 mag. Moreover, we show that the above time-based standardization corresponds to the generalization of the standardized candle method of Hamuy & Pinto for various epochs throughout the photospheric phase. To test the new tool, we construct Hubble diagrams for different subsamples of 50 low-redshift (cz < 10 4 km s −1 ) SNe II. For 13 SNe within the Hubble flow (cz CMB > 3000 km s −1 ) and with a well-constrained shock breakout epoch we obtain values of 68-69 km s −1 Mpc −1 for the Hubble constant and a mean intrinsic scatter of 0.12 mag or 6% in relative distances.

AN EXCESS OF MID-INFRARED EMISSION FROM THE TYPE Iax SN 2014dt

“…We note that SN 2014dt was discovered after peak brightness, but the light curves indicate that it peaked around October 20 (MJD = 56,950). This explosion date is comparable to the time of maximum deduced from spectral cross correlations (Ochner et al 2014;Foley et al 2015 Rodríguez et al 2014). While the former is consistent with the Tully-Fisher estimate (Schoeniger & Sofue 1997) and used to put limits on the progenitor system in Foley et al (2015), the larger distance makes SN 2014dt appear to have similar absolute magnitudes as SNe 2005hk and 2012Z, peaking at M 18 V~-mag.…”

SN 2017ein and the Possible First Identification of a Type Ic Supernova Progenitor

“…Poznanski et al (2009), based on assuming that SNe II-P are standardizable candles, estimated that the distance modulus to SN 2005ay is μ = 31.27 ± 0.13 mag (D = 17.9 Mpc). Rodríguez et al (2014), invoking a similar, color-based standardization of the absolute brightness of SNe II-P, found that μ = 31.75 ± 0.24 mag (22.4 Mpc) for their method in the V band and 31.70±0.23 mag (21.9 Mpc) in I. Several early Tully-Fisher estimates (Bottinelli et al 1984(Bottinelli et al , 1986) resulted in far shorter distances, with μ ≈ 28.7 ± 0.7 mag (D ≈ 5.7 Mpc), although Tully (1988) lists μ = 31.15 ± 0.40 mag (17.0 Mpc).…”

UBVRIz LIGHT CURVES OF 51 TYPE II SUPERNOVAE

“…These data have been used previously for the study of specific objects (Schmidt et al 1994b;Zampieri et al 2003;Hamuy et al 2009;Krisciunas et al 2009;Mazzali et al 2009;Bersten et al 2011;Takáts et al 2015;Kleiser et al 2011). The subsample of SNeIIP has been used for the determination of distances using the "Expanding Photosphere Method" (Schmidt et al 1994a;Jones et al 2009) and the "Standardized Candle Method" (Hamuy & Pinto 2002;Nugent et al 2006;Poznanski et al 2009;Hamuy 2004;Olivares et al 2010;Rodríguez et al 2014), and for the determination of bolometric corrections (Bersten & Hamuy 2009). Other studies that have relied on some of the objects in this sample also include: (1) Hamuy (2003a) examined the observed and physical properties of SNe II using both photometry and spectroscopy of a selection of 24 SNe II; (2) Anderson et al (2014) performed a characterization of the V-band light curves of an expanded sample of SNe II; and (3) Gutiérrez et al (2014) have correlated those properties with the Hα feature of their spectra.…”