Friday, February 3, 2012

Fermi LAT weekly report N. 190

Covered period: 2012 January 23-29
LAT Mission week: 190.57 - 191.57

  • A long-lasting M8.7-class solar flare was detected by the LAT on January 23, 2012. Significant gamma-ray emission above 100 MeV was detected in the 1-day time interval and three 6h time intervals suggesting temporally extended gamma-ray emission. Between 06:00 UT and 09:00 UT, with a flux of (24+/-3)x10^-6 photons cm^-2 s^-1, it overwhelmed the flux of the Vela pulsar and represented a factor of about 50 greater than the flux of the solar disk for the quiet Sun (see ATel#3886). This very bright gamma-ray activity was produced by the strong solar flare erupting on the Sun's northeastern hemisphere at 03:59 UT, originated from sunspot 1402, characterized by a very fast coronal mass ejection (CME) partially Earth directed. This produced therefore the strongest flare and radiation storm since 2005 bombarding our Earth.  A further X-class solar flare was detected in gamma-rays by the LAT on January 27.

  • LAT detected a GeV flare (daily-bin flux about 10^-6 photons cm^-2 s^-1) from a possible new extragalactic gamma-ray source (Fermi J0052+1110) on January 29, 2012. The preliminary best-fit location of the source is R.A.=13.09 deg,  Dec:11.16 deg (J2000) with a 68% containment radius of 37 arcmin. Although the error region is large, based on the current knowledge, it contains no members of known gamma-ray-producing object classes (see ATel#3904). Multiwavelength observations of the region will be useful to add information and help in identify new blazars for example.

  • PKS 1510-08 and B2 1520+31 in high state during the week (around or above the daily flux level of 10^-6 photons cm^-2 s^-1). PKS 1510-08 was in flaring activity reaching a daily flux level of about 2.4x10^-6 photons cm^-2 s^-1 on January 28.

  • PKS 1424-41, Mkn 421, GC 0109+224, PKS 0537-441, PKS 0521-36, 4C +28.07, B3 1343+451, B2 2155+31, PKS 1244-255, NGC 1275, PKS 0454-234, PKS 2326-502, PMN J0531-4827, 3C 66A, the other blazars of the week detected at least in one daily bin (all with flux below 10^-6 photons cm^-2 s^-1)

Fluxes are in the unit of photons/cm^2/s above 100 MeV.
All uncertainties are statistical only.

Note. All the flux reported above are by the ASP analysis and should be considered preliminary and should not be used for publication, however they are indicative of the flux range and the current status of a source. Source association is done on the basis of source location, considering spatial coincidence only, and it is not indicative of an identification. - Please acknowledge the LAT team if you use information from this report.

For questions and comments please contact:
- S. Ciprini (stefano.ciprini[at] for generic information related to this week
- Contact persons on this page for individual sources cited above.

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