Observed Spectral profile of M77

Date & Time: Nov 27 2011, 21:22 JST(+0900), 5min. exposed
Optical: Meade 25cm(10") Schmidt Cassegrain (f=2500mm, F10.0)
with SBIG DSS7 Spectrometer
Auto-guided with Meade LX200 Equatorial & Pictor 201 XT
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 lineHO IIIO IIIS II
Observed WL, λm6595.0 Å4883.7 Å4983.0 Å5031.9 Å6755.6 Å
 WL in literature, λ06562.9 Å4861.3 Å4959 Å5007 Å6730 Å
Red shift, z4.891×10-34.608×10-34.840×10-34.973×10-33.804×10-3
Recession velocity, v (km/s)1.464×1031.379×1031.448×1031.488×1031.139×103
Estimated distance, D (mill ly-yr)68.1764.2367.4569.3153.04
(average)64.44 mill. lt-yr

z= (λm0)/λ0
v= c*((1+z)2-1)/((1+z)2+1)
D= 3.26*v/H0
(million lt-yr)
  (c: velocity of light, H0=70 km/s/Mpc)
This page shows you the observed spectral profile of M77. Generally the seyfert galaxies including M77 have wealth of inter-stellar gaseous matters. We can detect clear emission lines like diffused and/or planetary nebulae, can easily estimate distances to the galaxies from red shifts of those lines.
A table in right has listed and indicated estimated distance to M77 from observed wavelengths of five lines. The value can be calculated as about 64 million light years under an assumption that the Hubble constant of H0 has 70 km/s/Mpc.

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