- Lizhong Zhang
- Identification of unidentified Fermi γ-ray sources
- Astronomy and Physics
Describe
your research
experience
My research focuses on observations of active galactic nuclei (AGN) and supermassive black holes at cosmological distances. This particular research focuses on the identification of unidentified Fermi γ-ray sources with millimeter-wave (mm) data from the South Pole Telescope (SPT).
The Fermi γ-ray Space Telescope (Fermi) has surveyed the entire sky at the highestenergy band of the electromagnetic spectrum. The majority of Fermi sources have counterpart identifications from multi-wavelength large-area surveys, particularly in the radio and x-ray bands. However, around 35% of Fermi sources remain unidentified, a problem exasperated by the low resolution. Understanding the nature of unidentified Fermi sources is one of the most pressing problems in γ-ray astronomy. At least some of the unidentified Fermi sources are flat-spectrum radio quasars which are extraordinarily bright at millimeter (mm) wavelengths. The mm wavelength is the most efficient means to identify blazars and possibly unidentified Fermi sources. The South Pole Telescope (SPT) with arcminute resolution at millimeter wavelengths has completed a survey covering a large fraction of southern extragalactic sky. Preliminary analysis shows that the SPT point source catalog provides candidates associated with 40% of the unidentified Fermi sources. This study will perform investigate the millimeter/γ-ray connection and unveil the missing counterparts of the unidentified Fermi sources.
As one of the recipient's of OUR's Summer Undergraduate Research Fellowships (2015), the results of Lizhong's research can be found here.
