Identification of a non-thermal X-ray burst with the Galactic magnetar SGR J1935+2154 and a fast radio burst using

As China's first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy satellite with the

[1] Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED)/ Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) observations of vertical profiles of the OH nightglow emission rates, temperature, and ozone are used along with a theoretical model of the OH nightglow to distinguish the dominant mechanism for the nightglow. From the comparison between the model fit and the observations we conclude that the chemical reaction O 3 + H→ OH(v ≤ 9) + O 2 leads to population distributions of vibrationally excited states that are consistent with the measurements. The contribution of the reaction HO 2 + O→ OH(v ≤ 6) + O 2 to the nightglow is not needed to reproduce the measurements above 80 km, at least for the emissions originating from vibrational transitions with v ≥ 4. The analysis also determines the best fits for quenching of OH(v) by O 2 and O. The results show that the quenching rate of OH(v) by O 2 is smaller and that the removal by O is larger than currently used for the analysis of SABER data. The rate constant for OH(v) quenching by O 2 decreases with temperature in the mesopause region. The vertical profiles of atomic oxygen and hydrogen retrieved using both 2.0 and 1.6 mm channels of Meinel band emission of the OH nightglow and the new quenching rates are slightly smaller than the profiles retrieved using only the 2.0 mm channel and the quenching rate coefficients currently used for the analysis of SABER data. The fits of the model to the observations were also used to evaluate two other assumptions. The assumption of sudden death quenching of OH by O 2 and N 2 (i.e., quenching to the ground state rather than to intermediate vibrational levels) leads to poorer agreement with the SABER observations. The question of whether the reaction with or quenching by atomic oxygen depends on the OH vibrational level could not be resolved; assumptions of vibrational level dependence and independence both gave good fits to the observed emissions.Citation: Xu, J., H. Gao, A. K. Smith, and Y. Zhu (2012), Using TIMED/SABER nightglow observations to investigate hydroxyl emission mechanisms in the mesopause region,

Abstract. Sudden stratospheric warmings (SSWs) are circulation anomalies in the polar region during winter. They mostly occur in the Northern Hemisphere and affect also surface weather and climate. Both planetary waves and gravity waves contribute to the onset and evolution of SSWs. While the role of planetary waves for SSW evolution has been recognized, the effect of gravity waves is still not fully understood, and has not been comprehensively analyzed based on global observations. In particular, information on the gravity wave driving of the background winds during SSWs is still missing.