Upper Limits on the Gamma-Ray Emission from the Microquasar V4641 Sgr

Abstract

Following a recent detection of TeV radiation by the Large High Altitude Air Shower Observatory and the High-Altitude Water Cherenkov Observatory, coincident with the direction of the microquasar V4641 Sgr, we search for possible GeV emission from this source. We explored the morphology and temporal features of the source as well as two nearby unassociated point sources, which could be a part of the extended structure of V4641 Sgr, and compared results with corresponding X-ray and TeV emissions. No significant gamma-ray signal linked to V4641 Sgr was detected in the energy range of 1–300 GeV. The 95% confidence level upper limits for the flux from the source, assuming both point and extended source models, were 5.38 × 10 ^−13 erg cm ^−2 s ^−1 and 1.12 × 10 ^−12 erg cm ^−2 s ^−1 , respectively. Additionally, no correlation between the gamma-ray light curve and X-ray outbursts was observed.

Keywords

• Gamma-ray astronomy