Observed Spectrum of NGC4051

Observed Spectral profile of NGC4051

Date & Time:	Feb 25 2023, from 21:51 to 22:12 JST(+0900)
	Composed 3 shots with 10 minutes exposed
Optical:	Meade 25cm(10") Schmidt Cassegrain (f=2500mm, F10.0)
	with SBIG DSS7 Spectrometer
	Auto-guided with Meade LX200 Equatorial & Lacerta M-GEN
Cooled CCD Camera:	SBIG ST-402ME (Temp.: -25°C)
Location:	Ooizumi, Hokuto city, Yamanashi pref.

Upper strip: taken spectrogram, Lower strip: stretched 3-pixel-width & pseudo-colored image

Emission line	Hα	Hβ	Hγ	O III	O III
Observed WL, λ_m	6574 Å	4868 Å	4355 Å	4966 Å	5014.7 Å
WL in literature, λ₀	6562.9 Å	4861.3 Å	4340.5 Å	4959 Å	5007 Å
Red shift, z	1.699×10^-3	1.372×10^-3	3.348×10^-3	1.412×10^-3	1.538×10^-3
Recession velocity, v	509.2 km/s	411.3 km/s	1003 km/s	423.2 km/s	461.0 km/s
Estimated distance, D	23.71 Mly	19.16 Mly	46.69 Mly	19.71 Mly	21.47 Mly
(average)	26.15 Mly

z= (λ_m-λ₀)/λ₀
v= c*((1+z)²-1)/((1+z)²+1)
D= 3.26*v/H₀ (Mly)
(c: velocity of light, H₀=70 km/s/Mpc)

This page shows you the observed spectral profile of the central part of NGC4051.
The profile shows emission line of the ionized oxygen atoms (O-III lines) besides the Balmer series from Hα to Hγ. A table in right has listed and indicated estimated distance to the galaxy from observed wavelengths. The value can be calculated as about 26 million light years under an assumption that the Hubble constant of H₀ has 70 km/s/Mpc.

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