Do supernovae indicate an accelerating universe?

Understand

In the late 1990's, observations of 93 Type Ia supernovae were analysed in the framework of the FLRW cosmology assuming these to be `standard(isable) candles'.

• It was thus inferred that the Hubble expansion rate is accelerating as if driven by a positive Cosmological Constant $\Lambda$.
• This is still the only direct evidence for the `dark energy' that is the dominant component of the standard $\Lambda$CDM cosmological model.
• Other data such as BAO, CMB anisotropies, stellar ages, the rate of structure growth, etc are all `concordant' with this model but do not provide independent evidence for accelerated expansion.