Interstellar medium around supernova remnants associated with gamma-ray sources

DUVIDOVICH, L.; PETRIELLA, A.; GIACANI, E.; DUBNER, G.

Cartagena de Indias

Congreso; XV Latin American Regional IAU Meeting Cartagena 2016; 2016

IAU

Supernova remnants (SNRs) are potential sources of gamma-rays, eitherthrough inverse Compton scattering of electrons off ambient photons orthrough the decay of neutral pions created by the collision of energeticprotons with dense ambient gas. The SNRs G298.6-0.0 and G298.5-0.3 areproposed to be associated to the gamma-ray sources 3FGL J1214.0-6236 and3FGL J1212.2-6251, respectively. They are located in a complex portionof the Galactic plane, also containing sources of powerful stellar windssuch as the star Wolf Rayet HD104994 and the HII regionsG298.559-00.114, G298.868-00.432 and G298.228-00.331 with ongoing starformation. We present a study of the neutral hydrogen distributiontowards the mentioned SNRs. We found a structure with ellipsoidalmorphology that encloses a region containing G298.5-0.3, G298.6-0.0,HD104994, G298.559-00.114 and G298.228-00.331. This HI feature isdetected in the velocity range 89-100 km s-1. We propose thatthe neutral gas would be the accelerated portion (which would explainits high radial velocity) of a gas shell swept up by a series ofexpansive and explosive events. The rest of this shell (at radialvelocities compatible with the systemic velocity of the objects) is notvisible because of confusion with galactic emission. We also inspectedthe distribution of the 12CO gas and found a dense molecularcloud at the systemic velocity of ? 22 km s-1corresponding to the kinematical distance of ? 10.4 kpc,compatible with the distance to the SNR G298.6-0.0. This molecular cloudis in spatial coincidence, projected in the sky plane, with the veryhigh energy source associated with the remnant. This fact, suggesting apossible hadronic origin for the gamma-rays emission. Regarding to theSNR G298.5-0.3, smaller and fainter than the previous one, the angularresolution of the molecular data is insufficient to draw meaningfulconclusions.