The Hubble Constant from Type Ia Supernovae Calibrated with the Linear and Nonlinear Cepheid Period-Luminosity Relations

Abstract

It is well known that the peak brightness of Type Ia supernovae calibrated with Cepheid distances can be used to determine the Hubble constant. The Cepheid distances to the host galaxies of the calibrating supernovae are usually obtained using the period-luminosity (P-L) relation derived from Large Magellanic Cloud (LMC) Cepheids. However, recent empirical studies provide evidence that the LMC P-L relation is not linear. Here we determine the Hubble constant using both the linear and nonlinear LMC Cepheid P-L relations as calibrating relations to four galaxies that hosted Type Ia supernovae. Our results suggest that the obtained values of the Hubble constant are similar. However, a typical error of ∼0.03 mag has to be added (in quadrature) to the systematic error for the Hubble constant when the linear LMC P-L relation is used, assuming that the LMC P-L relation is indeed nonlinear. This is important to minimize the total error on the Hubble constant in the era of precision cosmology. The Hubble constants calibrated from the linear and nonlinear LMC P-L relations are H 0 p 74.92 ‫ע‬ 2.28 (random) ‫ע‬ 5.06 (systematic) km s Ϫ1 Mpc Ϫ1 and H 0 p 74.37 ‫ע‬ 2.27 (random) ‫ע‬ 4.92 (systematic) km s Ϫ1 Mpc Ϫ1 , respectively. Hubble constants calculated using the Galactic P-L relation are also presented and briefly discussed.

Revisiting the baryon fractions of galaxy clusters: a comparison with WMAP 3-yr results

“…However, the large body of independent evidence in favour of h > 0.6 (e.g. Jones et al 2005; Riess et al 2005; York et al 2005; Ngeow & Kanbur 2006) makes this solution seem unlikely.…”

The detailed forms of the LMC Cepheid PL and PLC relations

“…Estimates of the effect of such small non‐linearities on the Cepheid distance scale and on Hubble's constant are given in Ngeow & Kanbur (2006c) and amount to 1–2 per cent. Such an error seems small but in the era of ‘precision cosmology’ with a drive towards a distance scale accurate to 5 per cent, such an effect is important.…”

“…Ngeow & Kanbur (2006c) estimate the error in estimating H 0 , if a linear Cepheid PL relation is assumed and the underlying relation is ‘non‐linear’ at a period of 10 d, and find this can lead to an error of about 1–2 per cent. Such an error seems small but with significant work being carried out to reduce zero point errors (Macri et al 2006), it is important to construct as accurate a distance scale as possible that is independent of the cosmic microwave background (CMB).…”

HNC, HCN and CN in Seyfert galaxies

“…The distances were calculated assuming a Hubble constant of H 0 = 74.37 ± 2.27 km s −1 Mpc −1 (Ngeow & Kanbur 2006).…”

“…Schilke et al 1992; 4× 6 a The Seyfert classification, positions (in equatorial J2000 coordinates) and heliocentric radial velocities were taken from NED. b The distances were calculated using the Hubble constant (H 0 ≈ 74.37 km s −1 Mpc −1 ) estimated by Ngeow & Kanbur (2006). c The source sizes of the CO 1−0 transition line were estimated from the maps presented in Koda et al (2002) for NGC 3079, Schinnerer et al (2000) for NGC 1068, Bryant et al (1999) for NGC 2623, Sandqvist (1999) for NGC 1365, and Papadopoulos & Allen (2000) for NGC 7469.…”