  Context - Circumstellar discs are ubiquitous around young stars, but rapidly
dissipate their gas and dust on timescales of a few Myr. The Herschel space
observatory allows for the study of the warm disc atmosphere, using
far-infrared spectroscopy to measure gas content and excitation conditions, and
far-IR photometry to constrain the dust distribution. Aims - We aim to detect
and characterize the gas content of circumstellar discs in four targets as part
of the Herschel science demonstration phase. Methods - We carried out sensitive
medium resolution spectroscopy and high sensitivity photometry at lambda
~60-190 micron using the Photodetector Array Camera and Spectrometer instrument
on the Herschel space observatory. Results - We detect [OI] 63 micron emission
from the young stars HD 169142, TW Hydrae, and RECX 15, but not HD 181327. No
other lines, including [CII] 158 and [OI] 145, are significantly detected. All
four stars are detected in photometry at 70 and 160 micron. Extensive models
are presented in associated papers.
