INTEGRAL/SPI and Fermi/GBM Observation of the 2012 March 7th Solar Flares

Abstract

We present preliminary results of INTEGRAL/SPI and Fermi/GBM observations of the X5.4 and X1.3 solar flares on 2012 March 7. The GOES X5 flare commenced at 00:04 UT and was followed by the X1 flare an hour later. The entirety of both flares was detected by INTEGRAL/SPI, whereas the Fermi/GBM observed the falling phase of the X5 and entirety of the X1 flare. The 2.2 MeV neutron capture line is very prominent in both flares as observed by SPI. We performed Monte Carlo simulations to obtain the response of the SPI matrix in such a non-standard configuration, in order to calculate the flux of the 2.2 MeV line measured with SPI. Our preliminary study shows that the 2.2 MeV flux obtained with SPI for the X1 flare is around 30% smaller than that obtained with Fermi/GBM. There are variety of reasons for this difference including uncertainty in the SPI response and background subtraction in the GBM.

INTEGRAL serendipitous observations of solar and terrestrial X-rays and gamma rays

“…The three most intense flares of the 23rd solar cycle have been studied with the SPI camera: SOL2003-10-28T11:10 (GOES class X17.2) (Gros et al, 2004;Kiener et al, 2006;Watanabe et al, 2006), SOL2003-11-04T19:50 (X28.0) (Watanabe et al, 2006;Harris et al, 2007) and SOL2005-09-07T17:40 (X17.0) (Harris et al, 2007;Watanabe et al, 2007). SPI spectra of two weaker flares of the current solar cycle were also extracted and analysed: SOL2012-03-07T00:24 (X5.4) and SOL2012-03-07T01:14 (X1.3) (Zhang et al, 2012).…”