[CLO2013] G070.3329+01.5864-1 , the SIMBAD biblio

Near-infrared H- and K-band spectra are presented for 247 objects, selected from the Red MSX Source (RMS) survey as potential young stellar objects (YSOs). 195 ( ∼ 80percent) of the targets are YSOs, of which 131 are massive YSOs (LBOL > 5x10³ L☉, M > 8 M☉). This is the largest spectroscopic study of massive YSOs to date, providing a valuable resource for the study of massive star formation. In this paper, we present our exploratory analysis of the data. The YSOs observed have a wide range of embeddedness (2.7 < AV < 114), demonstrating that this study covers minimally obscured objects right through to very red, dusty sources. Almost all YSOs show some evidence for emission lines, though there is a wide variety of observed properties. The most commonly detected lines are Brγ, H2, fluorescent Fe ii, CO bandhead, [Fe ii] and He i 2-1 1S-1P, in order of frequency of occurrence. In total, ∼ 40percent of the YSOs display either fluorescent Fe ii 1.6878µm or CO bandhead emission (or both), indicative of a circumstellar disc; however, no correlation of the strength of these lines with bolometric luminosity was found. We also find that ∼ 60percent of the sources exhibit [Fe ii] or H2 emission, indicating the presence of an outflow. Three quarters of all sources have Brγ in emission. A good correlation with bolometric luminosity was observed for both the Brγ and H2 emission line strengths, covering 1 < LBOL < 3.5x10⁵ L☉. This suggests that the emission mechanism for these lines is the same for low-, intermediate- and high-mass YSOs, i.e. high-mass YSOs appear to resemble scaled-up versions of low-mass YSOs.