SIMBAD references

We present a multi-wavelength study of the IR bubble G24.136+00.436. The J = 1-0 observations of ¹²CO, ¹³CO, and C¹⁸O were carried out with the Purple Mountain Observatory 13.7 m telescope. Molecular gas with a velocity of 94.8 km/s is found prominently in the southeast of the bubble, shaped as a shell with a total mass of ∼2x10⁴ M_☉. It was likely assembled during the expansion of the bubble. The expanding shell consists of six dense cores, whose dense (a few of 10³/cm3) and massive (a few of 10³ M_☉) characteristics coupled with the broad linewidths (>2.5 km/s) suggest that they are promising sites for forming high-mass stars or clusters. This could be further consolidated by the detection of compact H II regions in Cores A and E. We tentatively identified and classified 63 candidate young stellar objects (YSOs) based on the Spitzer and UKIDSS data. They are found to be dominantly distributed in regions with strong molecular gas emission, indicative of active star formation, especially in the shell. The H II region inside the bubble is mainly ionized by a ∼O8V star(s), of the dynamical age of ∼1.6 Myr. The enhanced number of candidate YSOs and secondary star formation in the shell as well as the timescales involved, indicate a possible scenario for triggering star formation, signified by the "collect and collapse" process.