How to calculate luminosity in g-band from absolute AB magnitude and luminosity distance?
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Hello Mate!!
Consider the g-band which typically has a λeff=467 nmλeff=467 nm and a Δλ=100 nmΔλ=100 nm. Given this galaxy has an apparent AB magnitude ofmg=22.5mg=22.5 and luminosity distance of 1991 Mpc1991 Mpc(i.e. z=0.355z=0.355 if you are curious), what is its luminosity? I know I shold use the following equation, but I don't know what value to pick for M⊙M⊙.
L/L⊙=100.4(M⊙−M)L/L⊙=100.4(M⊙−M)
I tried 5.12 from a website which is the value of M⊙M⊙ in g-band but it gives me a different answer compared to when I calculate luminosity using flux:
L=4πd2LfνΔνL=4πdL2fνΔν
where fνfν is flux density and ΔνΔν is the frequency width of the band (this is an approximation to the integration over frequency, assuming bands are step functions).
Consider the g-band which typically has a λeff=467 nmλeff=467 nm and a Δλ=100 nmΔλ=100 nm. Given this galaxy has an apparent AB magnitude ofmg=22.5mg=22.5 and luminosity distance of 1991 Mpc1991 Mpc(i.e. z=0.355z=0.355 if you are curious), what is its luminosity? I know I shold use the following equation, but I don't know what value to pick for M⊙M⊙.
L/L⊙=100.4(M⊙−M)L/L⊙=100.4(M⊙−M)
I tried 5.12 from a website which is the value of M⊙M⊙ in g-band but it gives me a different answer compared to when I calculate luminosity using flux:
L=4πd2LfνΔνL=4πdL2fνΔν
where fνfν is flux density and ΔνΔν is the frequency width of the band (this is an approximation to the integration over frequency, assuming bands are step functions).
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Hey !
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Flux and Magnitudes A2290-13 4 A2290-13 Flux and Magnitudes 7 Energy Flux and Luminosity The Energy Flux, F, is the power per unit area radiated from an object.
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Thanks !
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