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 line | Hα | Hβ | O III | O III | S II |
|---|
| Observed WL, λm | 6595.0 Å | 4883.7 Å | 4983.0 Å | 5031.9 Å | 6755.6 Å |
| WL in literature, λ0 | 6562.9 Å | 4861.3 Å | 4959 Å | 5007 Å | 6730 Å |
| Red shift, z | 4.891×10-3 | 4.608×10-3 | 4.840×10-3 | 4.973×10-3 | 3.804×10-3 |
| Recession velocity, v (km/s) | 1.464×103 | 1.379×103 | 1.448×103 | 1.488×103 | 1.139×103 |
| Estimated distance, D (Mly) | 68.17 | 64.23 | 67.45 | 69.31 | 53.04 |
| (average) | 64.44 Mly |
|---|
z= (λm-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)
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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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