Radio study of TeV sources from new GMRT observations

SUPAN L.; CASTELLETTI G.; JOSHI B.C., SURNIS M.; SUPANITSKY D.

Pune

Congreso; 32nd Meeting of the Astronomical Society of India; 2015

Indian Institute of Science Education and Research Mohali

A number of TeV sources have been discovered by High Energy Stereoscopic System (HESS) in the last decade. Out of these, TeV sources associated with Supernova Remnants (SNRs) are particularly important due to the possibility of presence of a putative pulsar and associated Pulsar Wind nebula, which can power the TeV source by leptonic mechanisms. Alternatively, these sources can also be powered by a hadronic scenario due to interaction of SNR with its surrounding. Here, we report on results from a project, being carried out with the GMRT, to understand the nature of these sources. We have completed a study of two such sources and work is in progress for three more sources. In particular, recent results of simultaneous imaging and pulsar observations of HESS J1818-154/G15.4+0.1 with the GMRT will be presented. No spectral index trace, indicating a radio counterpart to the pulsar wind nebula proposed from X-ray observations, was found in this source. In addition, the search for radio pulsations yielded negative results. Presence of interacting molecular cloud, evidenced in CO observations and an impressive agreement between emission at far infrared wavelengths and the molecular cloud, suggest a hadronic origin of TeV emission. However, our modeling of SED for the source implies that the TeV emission could be due to either a purely hadronic or leptonic model and furthersensitive observations at MeV energies are needed to better constrain its SED.