Using the 44 years (1958‐2001) ECMWF (European Centre for Medium‐rangeWeather Forecast) data sets and ozone mixing rate at tropopause, the global cross‐tropopause ozone mass flux (CTF) has been calculated by Wei formula. The results are as follows: (1) The global CTF presents zonal and meridional wave patterns which have not reached to the tropic tropopause controlling area by crossing tropopause break, prominently from the Mediterranean area, through the Iran Plateau, Tibetan Plateau, south of Japan, to the North Pacific and in Southern Hemisphere. The spatial variation of STE (Stratosphere‐Troposphere Exchange) is uniform over oceans and complicated over continents. The upward and downward flux peak values are −4μg·m−2·s−1 and 2.5μg·m−2·s−1 in the Northern Hemisphere, and –2.5 μg·m−2·s−1 and 1.5μg·m−2·s−1 in the Southern Hemisphere. (2) The zonal means of ozone flux vary with the latitudes, and the flux is unsymmetrical in the Northern and Southern Hemispheres for the general effects transfer from stratosphere to troposphere. The ozone flux which has notable seasonal variation presents the geographical distribution changing with seasons, and it is dominated by seasonal variation of atmospheric environment beside by seasonal change of the tropopause. (3) The seasonal and annual variations of pure ozone flux in Southern Hemisphere have two peak values which show the structure of unsymmetrical seasonal wave, which is completely contrary to Northern Hemisphere. Global average CTF exhibits remarkable characteristic of QBO (Quasi‐Biennial Oscillation). Interannual change of STT can be divided into four phases, with a balanced phase in the 1960s, an enhanced phase in the 1970s, another balanced phase in the 1980s and a remarkable variation phase in the 1990s. The downward ozone flux maximums appear in 1977, 1990 and 1998, the minimums in 1993 and 1996, respectively.

We analyze the quasiperiodic oscillation (QPO) of the historical light curve of flat-spectrum radio quasars PKS 0405-385 detected by the Fermi Large Area Telescope from 2008 August to 2021 November. To identify and determine the QPO signal of PKS 0405-385 in the γ-ray light curve, we use four time series analysis techniques based on frequency and time domains, i.e., the Lomb–Scargle periodogram (LSP), the weighted wavelet z-transform (WWZ), the REDFIT, and the epoch folding. The results show that PKS 0405-385 has a quasiperiodic behavior of ∼2.8 yr with the significance of ∼4.3σ in Fermi long-term monitoring. Remarkably, we also performed QPO analysis in the G-band light curve observed from 2014 October to 2021 October using LSP and WWZ technology, and the results (∼4σ of significance) are consistent with the periodic detection in γ-ray. This may imply that the optical emission is radiated by an electron population in the same way as the γ-ray emission. In discussing the possible mechanism of quasiperiodic behavior, either the helical motion within a jet or the supermassive black hole binary system provides a viable explanation for the QPO of 2.8 yr, and the relevant parameters have been estimated.

In this paper, $\sim12-$year long$-$term Pass 8 data from \emph{Fermi} Large Area Telescope for the 157 globular clusters are carefully re-analyzed. Besides the 31 globular clusters reported in the fourth \emph{Fermi} Large Area Telescope catalogue Data Release 2, NGC 1851 is identified as a gamma-ray emitter and the significant gamma$-$ray emissions from NGC 6715 and NGC 6723 are detected. Especially NGC 6715 locates at a distance of 26.8 kpc, so far it is the farthest globular cluster detected in gamma-rays. A detailed analysis for these three globular clusters has been performed, but their gamma-ray pulsation emissions or flux variabilities are not found. The numbers of millisecond pulsars in these globular clusters are estimated under the assumption that each millisecond pulsar inside globular clusters emits a similar amount of gamma$-$rays. Some possible origins, such as MSPs, pulsar binary systems and/or dark matter, of gamma−ray emission from globular clusters are discussed.

The events from 157 globular clusters (GCs) are analyzed by using 12{-}year long{-}term Pass 8 data from Fermi Large Area Telescope. Besides the 34 GCs reported in previous literatures, four additional GCs (ESO 452-SC11, NGC 6380, Palomar 6 and UKS 1) in the Milky Way are detected as gamma-ray GC candidates. Especially for UKS 1, it is known as the faintest GCs in long-wavelength bands. The further data analysis has been performed for the four GCs. While no pulsars are determined in radio and/or X-ray wavelengths so far, their gamma-ray pulsation emissions are not found, and no significant gamma-ray flux variability is detected. The numbers of MSPs within the four GCs are estimated based on the assumption that the MSPs within GC emit similar amount of gamma-rays. The gamma-ray results reported here could help us better understand the nature of gamma-ray emission origins for GCs.

PMN J0218–2307 (4FGL J0218.9–2305) is classified as a blazar candidate with unknown type (BCU) in the fourth source catalog from the Fermi Large Area Telescope (Fermi-LAT). With the updated Fermi-LAT Pass 8 data, the γ-ray flaring activity toward PMN J0218–2307 is detected. The test statistic (TS) value of PMN J0218–2307 in energy band of 100 MeV–500 GeV is 133.893 with a significance level of 10.96σ. The maximum-likelihood photon flux is (8.131 ± 1.359) × 10−9 ph cm−2 s−1. A significant γ-ray flare in the period from 2008 August 4 to 2019 August 25 is found from the source. The spectral characteristics of GeV energy band of PMN J0218–2307 is similar to that of flat-spectrum radio quasars (FSRQs) in the local Universe.