Awakening of two $\gamma$-ray high redshift flat-spectrum radio quasars in the southern hemisphere
| Autor: | Li, Shang, Sun, Lu-Ming, Liao, Neng-Hui, Fan, Yi-Zhong |
|---|---|
| Rok vydání: | 2020 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.3847/1538-4357/abab03 |
| Popis: | High-redshift blazars are valuable tools to study the early Universe. So far only a handful of $\gamma$-ray blazars have been found at redshifts above 3. $\gamma$-ray signals are detected in the direction of PMN J2219-2719 ($z=3.63$) and PMN J2321-0827 ($z=3.16$) by analyzing the 10-year $Fermi$-LAT Pass 8 data. PMN J2219-2719 is not distinguished from the background in the global analysis. During the 5-month epoch, the TS value is 47.8 and the flux is more than 10 times of the 10-year averaged flux. In addition, the angular distance between the $\gamma$-ray position and the radio position of PMN J2219-2719 is only ${0.04}^{\circ}$. Moreover, the $\gamma$-ray and infrared light curves of long time scale are very similar, which support the association between the $\gamma$-ray source and PMN J2219-2719. The global analysis of PMN J2321-0827 suggest a new $\gamma$-ray source, during the flare phase, the TS value is 61.4 and the $\gamma$-ray flux increased significantly. The association probability suggests that PMN J2321-0827 may be the counterpart of the new $\gamma$-ray source. In the future, the number of high-redshift $\gamma$-ray sources will increase by combining $Fermi$-LAT and the upcoming Large Synoptic Survey Telescope. Comment: 12 pages, 6 figures. Accepted for publication in ApJ |
| Databáze: | arXiv |
| Externí odkaz: |
|