NGC 491A
Observation
| Spectrum ID | 9991156_sp1 |
|---|---|
| Alt name | g0120050-335401 |
| z | 0.0119 |
| RA, Dec | 20.0211, -33.9002 |
| MJD | 60224.54 |
| SNR/Å B/R | 11.4/20.4 |
| Obs Airmass | 1.05 |
| SMSS ID | 9991156 |
| Closest SMSS | 1.97'', 1013853154 |
| SMSS Mean r6"ap | 17.1 ± 0.1 |
| 2MASS Kext | 12.3 ± 0.1 |
AGN Properties
| Spectrum Type | SF |
|---|---|
| Quality Flag | good |
| AGN reference | 6dFGS |
| MW E(B−V) | 0.027 |
| Power law αν | -1.32 ± 0.04 |
| log L5100,AGN | 41.43 ± 0.02 |
| log HβBr/[O III] | — |
| log ML5100/M☉ | — |
| log MHα/M☉ | — |
| log MHβ/M☉ | — |
| log M[O III]/M☉ | — |
Spatial extraction & sky subtraction region
Spaxel scale: 1 arcsec² — Flux units: erg s⁻¹ cm⁻² Å⁻¹
Apertures: object (solid), background (dashed)
Spectrum decomposition
Emission line measurements
| Line | log L (erg s⁻¹) | FWHM (km s⁻¹) | σ (km s⁻¹) | EW (Å) |
|---|---|---|---|---|
| Hγ Narrow | 38.29 ± 0.08 | 149 ± 62 | 83 ± 32 | 3.28 ± 0.92 |
| Hγ Broad | — | — | — | — |
| [O III] 4364 | — | — | — | — |
| He II Narrow | — | — | — | — |
| He II Broad | 38.51 ± 0.17 | 2140 ± 62 | 909 ± 25 | 5.71 ± 1.18 |
| Hβ Narrow | 38.84 ± 0.02 | 149 ± 62 | 83 ± 32 | 12.50 ± 0.73 |
| Hβ Broad | — | — | — | — |
| [O III] 5007 | 38.46 ± 0.04 | 149 ± 62 | 83 ± 32 | 5.29 ± 0.69 |
| He I Narrow | 37.51 ± 0.34 | 145 ± 62 | 59 ± 25 | 0.68 ± 0.29 |
| He I Broad | 38.34 ± 0.17 | 1494 ± 62 | 634 ± 25 | 4.52 ± 1.70 |
| [O I] 6300 | 37.66 ± 0.16 | 145 ± 62 | 59 ± 25 | 1.01 ± 0.22 |
| Hα Narrow | 39.33 ± 0.01 | 145 ± 62 | 59 ± 25 | 48.31 ± 0.26 |
| Hα Broad | — | — | — | — |
| [N II] 6585 | 38.80 ± 0.01 | 145 ± 62 | 59 ± 25 | 14.12 ± 0.23 |
| [S II] 6718 | 38.76 ± 0.01 | 145 ± 62 | 59 ± 25 | 13.08 ± 0.24 |
| [S II] 6732 | 38.59 ± 0.02 | 145 ± 62 | 59 ± 25 | 8.91 ± 0.22 |
All narrow line widths are tied to narrow [O III] 5007Å. [O III] 5007Å and narrow Hβ include a second narrow component not tied to other narrow lines.
Emission summary
| Hα Broad SNR | 0.00 |
|---|---|
| Hβ Broad SNR | 0.00 |
| Hγ Broad SNR | 0.00 |
| AGN frac | 0.43 |
| Host frac | 0.57 |
| log L5100,Host | 41.56 |
| Fe II/Hβ | — |
| Fe II/[O III] | 3.55 |
Quality flags
spurious_hab/hbb | 0.0/0 |
|---|---|
l5100 | 2 |
balmer | 2 |
balmer_snr | 2 |
hb_width | 2 |
balmer_width | 2 |
Hα mass estimates from Cho+2023. Remaining mass estimates from R–L relations in Wang & Woo 2024 and zero-points from Amrutha+2026.