Morphology and Spectral Study of TeV Halo Candidates, Geminga and Monogem, with the HAWC gamma-ray observatory*

The origin of the local positron excess above 10 GeV reported by PAMELA, Fermi-LAT, and AMS-02 remains unclear. Dark matter particle mechanisms such as annihilation and pulsar wind nebulae are likely sources of high energy electron/positron emission. Here the extended gamma-ray regions coinciding with two nearby mid-aged pulsars, Geminga and PSR B0656+14 (Monogem) are of particular interest. The High Altitude Water Cherenkov (HAWC) collaboration previously derived a high efficiency in emission of electrons and positrons but a diffusion coefficient that differed by a factor of 100 from the average galactic value with 500 days data. This result suggested no strong contribution to the above excess from these two sources. However, this led to the concept of inverse Compton gamma-ray halos, TeV halos. With an improved point spread function (PSF) and ~1400 days of data, I present a multi-source morphology and spectral study using a halo template model that allows for the direct analysis of energy dependence in diffusion coefficient for different positron spectral indices.