Star formation activity in the vicinity of the HII region G034.8-0.7 and the SNR W44: an IR and molecular study.

S. PARON, M. E. ORTEGA, M. RUBIO, G. DUBNER

Rio de Janeiro

Congreso; XXVII IAU General Assembly; 2009

IAU

We present an infrared and molecular study towards youngstellar object (YSO) candidates identified at the border of the HII regionG034.8-0.7 that is evolving within a molecular cloud shocked by the SNR W44.This study is based on near and mid infrared data as extracted from the2MASS and Spitzer databases and observations of the 12CO J=3--2,13CO J=3--2, HCO+ J=4--3 and CS J=7--6 lines obtained from theAtacama Submillimeter Telescope Experiment (ASTE).Based on the infrared study we propose that the source 2MASS 18564827+0118471(hereafter IR1) is a massive YSO candidate. We discovered a bipolar 12COoutflow in the direction of the line of sight and a HCO+ clump towards IR1,confirming that it is a YSO. From the detection of the CS J=7--6 line we inferthe presence of high density (>10^7 cm-3) and warm (>60 K) gas towardsIR1, probably belonging to the protostellar envelope where the YSO is forming.Finally, we investigated the possible genetic connection of IR1 with the SNR andthe HII region. By comparing the dynamical time of the outflows and the age of theSNR W44, we conclude that the possibility of the SNR has triggered the formation ofIR1 is unlikely. On the other hand, we suggest that the expansion of the HII regionG034.8-0.7 is responsible for the formation of IR1 through the "collect and collapse"process.