The Absolute Magnitude of the Sun in Several Filters

Abstract

This paper presents a table with estimates of the absolute magnitude of the Sun and the conversions from $vegamag$ to the AB and ST systems for several wide-band filters used in ground and space-based observatories. These estimates use the dustless spectral energy distribution (SED) of Vega, calibrated absolutely using the SED of Sirius, to set the $vegamag$ zero-points and a composite spectrum of the Sun that coadds space-based observations from the ultra-violet to the near infrared with models of the Solar atmosphere. The uncertainty of the absolute magnitudes is estimated comparing the synthetic colors with photometric measurements of solar analogs and is found to be $\sim$ 0.02 magnitudes. Combined with the uncertainty of $\sim$ 2% in the calibration of the Vega SED, the errors of these absolute magnitudes are $\sim$ 3--4%. Using these SEDs, for the three of the most utilized filters in extragalactic work the estimated absolute magnitudes of the Sun are $M_B$ = 5.44, $M_V$ = 4.81 and $M_K$ = 3.27 mag in the $vegamag$ system and $M_B$ = 5.31, $M_V$ = 4.80 and $M_K$ = 5.08 mag in AB.