PKS 0346−27
Blazar in the constellation of Fornax
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PKS 0346−27 is a blazar located in the constellation of Fornax. Its redshift is (z) 0.991 and as such lies at a distance of 7.8 billion light-years from Earth.[1] This object is also classified as a flat-spectrum radio quasar with its radio spectrum seeming to appear flat with its radio source being first identified in 1966 by astronomers.[2][3]
| PKS 0346−27 | |
|---|---|
The blazar PKS 0346−27 | |
| Observation data (J2000.0 epoch) | |
| Constellation | Fornax |
| Right ascension | 03h 48m 38.14s[1] |
| Declination | −27° 49′ 13.56″[1] |
| Redshift | 0.991000[1] |
| Heliocentric radial velocity | 297,094 km/s[1] |
| Distance | 7.891 Gly |
| Apparent magnitude (V) | 18.63 |
| Apparent magnitude (B) | 20.08 |
| Characteristics | |
| Type | FSRQ[1] |
| Other designations | |
| 6dF J0348381−274914, PKS 0346−279, LEDA 2823683, OE −278, NVSS J034838−274914, WMAP 129, 4FGL J0348.6−2749[1] | |
Description
PKS 0346−27 is highly active on the electromagnetic spectrum in terms of emission of gamma-rays, although it can be categorized as a Low-Synchrotron-Peaked Blazar during its quiescent period because of the low spectral energy distribution peak.[2] On February 2, 2018, it was shown to be in a high-flux state with its gamma-ray flux reaching levels of 1.0 ± 0.2 × 10−6 photons cm−2 s-1 upon detection by Fermi Gamma-ray Space Telescope.[4] The next time the object displayed immense activity, was on April 24, 2019, where it reached a new historic high gamma-ray flux level of 3.2 ± 0.3 × 10−6 photons cm−2 s−1.[5] Subsequently, it displayed more renewed activity recorded in February 2020 and on November 24, 2021.[6][7] An optical flare was also observed, in addition to gamma-rays where the object brightened in brightness.[8][9]
Because of its powerful activity, PKS 0346−27 has been studied in detail. Data from a multiwavelength temporal and spectral study showed the object had multiple flaring episodes based on its gamma-ray light curve analysis from data collected over more than 2 years, with its minimum variability time estimated as 1.34 ± 0.3 days, indicating the source of PKS 0346−27 is compact. Astronomers also suggested the variability of the flares were caused by emission region interactions through stationary shock waves.[10]
It is suggested PKS 0346−27 is a very-high energy emitter. Based on results, it underwent significant flaring activity on November 2, 2021, with a daily flux level of 1.8 ± 0.2 × 10−6 photons cm−2 s−1, an increase of 200 folds since its average flux measured by fourth Fermi-LAT catalogue. The spectral index of the object measured by High Energy Stereoscopic System (HESS) was shown to have a soft index with a unit greater than four.[11]
A quasi-periodic oscillation was detected in PKS 0346−27 during the observations conducted between December 2018 and January 2022. Results showed the periodicity is 100 days long and was likely caused by enhanced radio emission travelling in a helical direction inside a curved radio jet. The supermassive black hole mass was found to be 9.48 × 109 M☉.[12]