| TON S180 | |
|---|---|
 TON S180, as seen onDESI Legacy Surveys | |
| Observation data (J2000epoch) | |
| Constellation | Cetus |
| Right ascension | 00h 57m 19.94s |
| Declination | −22° 22′ 59.10″ |
| Redshift | 0.061980 |
| Heliocentric radial velocity | 18,581km/s |
| Distance | 827Mly (253.55Mpc) |
| Apparent magnitude (V) | 14.34 |
| Apparent magnitude (B) | 14.6 |
| Characteristics | |
| Type | SABa, Sy1.2 |
| Apparent size (V) | 0.35' x 0.29' |
| Other designations | |
| IRAS F00548-2238, PHL 912, EUVE J0057-22.3,LEDA 87796,RX J0057.3-2222, LEDA 815045 | |
TON S180 (abbreviation ofTonantzintla S180) is aSeyfert galaxy located in the southern constellation ofCetus. It is located 827 millionlight years fromEarth.[1] The galaxy is classified as aquasi-stellar object (QSO) because of its highluminosity and is located 3.6degrees northeast fromNGC 253, and 2.8 degrees southeast fromNGC 247.[2]
TON S180 was first discovered in the year 1958 by Mexicanastronomers who catalogued the object as entry number 180 under theTonantzintla Blue Stellar Object Survey. In 1962 the object was then catalogued as PHL 912 by the Palomar-Haro-Luyten Survey. Subsequently, in 1980 and 1995, TON S180 was detected as anultraviolet emitter by the Kiso Schmidt Camera Survey and theExtreme Ultraviolet Explorer.[2]
TON S180 is categorized a narrow-line Seyfert galaxy.[3][4][5] It has a prototype 'bare'active galactic nucleus with a totalinfrared luminosity of Lbol ~ 5 x1045erg s−1, but no traces of absorption.[4] The galaxy has a vertical soft X-ray spectrum measuring aphoton index of Γ = 2.68[6] and a Hβ width measuring 900 km s−1.[7] In addition, TON S180 has a short galacticcolumn density along theline of sight, approximately NH = 1.52 x 1020 cm−2. It has anabsolute magnitude of MB = -23.1[8] and an estimated centralblack hole mass of M ~ 2 x 107 MΘ.[9] According to aspectral energy distribution presented for TON S180, it is shown moreenergy is emitted in the 10-100 eV band.[9]
The host galaxy of TON S180 is aspiral galaxy of type SABa classification. The galaxy appears as astar-like object found obscured by its own circular halo.[2] It contains a sharp and narrow iron line, as well as having a smooth soft excess unable to be produced by relativistic reflection based on observations of its X-rayspectrum.[10]
TON S180 is known to be extremelyvariable compared to other Seyfert galaxies. Every few thousand seconds, itsX-ray flux would show a factor of 2 variability, which, comparing to both the 0.5-2 and 2-10keV bands, the former has a significantly high σ 2root mean square.[8] According to theFar Ultraviolet Spectroscopic Explorer, which acquired a high-resolution spectra for the galaxy, TON S180 shows ultraviolet absorption by five-timesionized oxygen but nohydrogen absorption, indicating its absorbing gas is currently in a high ionization state.[11]
