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Table 1.

Upper limits in the [0.1−10] TeV range on known hard X-ray from SGR 1935+2154 observed by different satellites.

# Time of Arrival Instrument Exposure Rbkg N5σ NON sUL Flux UL Fluence UL
ISOT UTC 108 cm2 s s−1 10−8 cm−2 s−1 10−9 erg cm−2
1 2021-07-07 00:33:31.670 Fermi-GBM 1.448 0.81 ± 0.02 4 0 2.16 1.49 1.09
2 2021-09-10 23:40:34.460 Fermi-GBM 1.485 1.05 ± 0.03 4 0 2.19 1.47 1.08
3 2021-09-11 22:51:41.600 GECAM 1.430 0.95 ± 0.03 4 0 2.17 1.52 1.11
4 2021-09-11 23:55:45.872 NICER 1.485 1.01 ± 0.03 4 0 2.18 1.47 1.07
5 2021-09-12 00:34:37.450 GECAM 1.491 0.61 ± 0.03 4 0 2.13 1.43 1.04
6 2021-09-12 00:45:49.400 GECAM 1.491 0.66 ± 0.03 4 0 2.14 1.43 1.05
7 2021-09-12 22:16:36.200 GECAM 1.296 0.68 ± 0.02 4 1 3.86 2.97 2.17
8 2021-09-12 23:19:32.080 Fermi-GBM 1.430 1.04 ± 0.03 4 0 2.18 1.53 1.12
9 2021-09-13 00:27:25.200 GECAM 1.485 1.04 ± 0.03 4 0 2.18 1.47 1.07

Stacked δt = 0.9 s 13.041 0.87±0.04 8 1 3.57 0.27 0.20

Notes. The exposure is given for a δt = 0.1 s observation time assuming a power-law spectrum with index 2. The background rate, Rbkg, was estimated in a OFF region and was used to estimate N5σ, the counts needed for a 5σ detection. The NON counts were evaluated in a 0.1 s time window centred around the burst ToA and were used to compute sUL according to Eq. (12). The photon flux ULs were given by dividing sUL over the exposure. The fluence ULs were obtained converting the photon flux into energy flux and integrating over δt. The stacked entry assumes an average Rbkg and effective area. Burst #1 was detected by Hamburg et al. (2021a,b), Xiao et al. (2021), Nakahira et al. (2021), Ridnaia et al. (2021b). #2 by Roberts et al. (2021), Roberts & Wood (2021). #3, #5 and #6 by Xue et al. (2021). #4 by Guver et al. (2021). #8 by Roberts & Fermi GBM Team (2021). #7 and #9 by Cai et al. (2021).

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