Peering into the Milky Way by FAST:Ⅰ. Exquisite HI structures in the inner Galactic disk from the piggyback line observations of the FAST GPPS survey

作者：Tao Hong^*; JinLin Han^*; LiGang Hou; XuYang Gao; Chen Wang; Tao Wang

来源：Science China Physics,Mechanics & Astronomy, 2022, 65(12): 7-21.

Neutral hydrogen(Hi) is the fundamental component of the interstellar medium. The Galactic Plane Pulsar Snapshot(GPPS) survey is designed for hunting pulsars by using the Five-hundred-meter Aperture Spherical radio Telescope(FAST) from the visible Galactic plane within |b| ≤ 10°. The survey observations are conducted with the L-band 19-beam receivers in the frequency range of 1.0-1.5 GHz, and each pointing has an integration time of 5 min. The piggyback spectral data simultaneously recorded during the FAST GPPS survey are great resources for studies on the Galactic Hi distribution and ionized gas. We process the piggyback Hi data of the FAST GPPS survey in the region of 33°≤ l ≤ 55°and |b| ≤ 2°. The rms of the data cube is found to be approximately 40 m K at a velocity resolution of 0.1 km s-1, placing it the most sensitive observations of the Galactic Hi by far.The high velocity resolution and high sensitivity of the FAST GPPS Hi data enable us to detect weak exquisite Hi structures in the interstellar medium. Hi absorption line with great details can be obtained against bright continuum sources. The FAST GPPS survey piggyback Hi data cube will be released and updated on the web: http://zmtt.bao.ac.cn/Milky Way FAST/.

• 单位
  中国科学院大学