A multiwavelength study of the star forming region IRAS 18544+0112

Aims. This work aims at investigating the molecular and infrared components in the massive young stellar object (MYSO) candidate IRAS 18544+0112. The purpose is to determine the nature and the origin of this infrared source. Methods. To analyze the molecular gas towards IRAS 18544+0112, we have carried out observations in a 9000 × 9000 region around l = 34. 69, b = –0. 65, using the Atacama Submillimeter Telescope Experiment (ASTE) in the 12CO J=3–2, 13CO J=3– 2, HCO+J=4–3 and CS J=7–6 lines with an angular resolution of 2200. The infrared emission in the area has been analyzed using 2MASS and Spitzer public data. Results. From the molecular analysis, we find self-absorbed 12CO J=3–2 profiles, which are typical in star forming regions, but we do not find any evidence of outflow activ- ity. Moreover, we do not detect either HCO+J=4–3 or CS J=7–6 in the region, which are species normally enhanced in molecular outflows and high density envelopes. The 12CO J=3–2 emission profile suggests the presence of expanding gas in the region. The Spitzer images reveal that the infrared source has a conspicuous extended emission bright at 8 μm with an evident shell-like morphology of 1.05 in size ( 1.4 pc at the proposed distance of 3 kpc) that encircles the 24 μm emission. The non-detection of ionized gas related to IRAS 18544+0112 together with the fact that it is still embedded in a molecular clump suggest that IRAS 18544+0112 has not reached the UCHII re- gion stage yet. Based on near infrared photometry we search for YSO candidates in the region and propos that 2MASS 18565878+0116233 is the infrared point source associ- ated with IRAS 18544+0112. Finally, we suggest that the expansion of a larger nearby HII region, G034.8−0.7, might be related to the formation of IRAS 18544+0112.S.P. is grateful to the staff of ASTE for the support received during the observations, especially to Juan Cort´es. S.P. acknowledges the support of Viviana Guzm´an during the observations. M.O. is a doctoral fellow of CONICET, Argentina. S.P., S.C., G.C., and G.D. are members of the Carrera del Investigador Cient´ıfico of CONICET, Argentina. This work was partially supported by Argentina grants awarded by CONICET, UBA and ANPCYT. M.R. is supported by the Chilean Center for Astrophysics FONDAP No. 15010003. M.R. and S.P. acknowledge support from FONDECYT N 1080335. This work has made use of GLIMPSE and MIPSGAL data obtained with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407. We also used data products from the Two Micron All Sky Survey, the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NAS