A multiwavelength study of the massive star-forming region IRAS 06055+2039 (RAFGL 5179)

Abstract

Aims. We present a multiwavelength study of the massive star-forming region associated with IRAS 06055+2039. Methods. Narrow-band near-infrared (NIR) observations were carried out with UKIRT-UFTI in molecular hydrogen and Brγ lines to trace the shocked and ionized gases, respectively. We have used 2MASS JHK s data to study the nature of the embedded cluster associated with IRAS 06055+2039. The radio emission from the ionized gas was mapped at 610 and 1280 MHz using the Giant Metrewave Radio Telescope (GMRT), India. Emission from warm dust and the unidentified infrared bands (UIBs) was estimated using the mid-infrared (8-21 µm) data from the MSX survey. Submillimetre emission from the cold dust at 450 and 850 µm was studied using JCMT-SCUBA. Results. For the infrared cluster associated with IRAS 06055+2039, we obtain a power-law slope of 0.43 ± 0.09 for the K s -band luminosity function (KLF), which is in good agreement with other young embedded clusters. We estimate an age of 2-3 Myr for this cluster. Apart from the diffuse emission, the high-resolution 1280 MHz map also shows the presence of several discrete sources that possibly represent high-density clumps. The morphology of shocked molecular hydrogen forms an arc towards the N-E of the central IRAS point source and envelopes the radio emission. Submillimetre emission shows the presence of a dense cloud core that is probably at an earlier evolutionary stage compared to the ionized region with shocked molecular gas lying between the two. The total mass of the cloud is estimated to be ∼7000-9000 M from the submillimetre emission at 450 and 850 µm. Conclusions. The multiwavelength study of this star-forming complex reveals an interesting scenario where regions are at different stages in the evolution of star formation.Key words. infrared: ISM -radio continuum: ISM -ISM: H II regions -ISM: individual objects: IRAS 06055+2039 IntroductionMassive stars are preferentially formed in dense cores of molecular clouds. They remain deeply embedded in the prenatal molecular gas and obscuring dust and their pre-main-sequence (PMS) time scales are much shorter compared to the low mass stars. The luminous high-mass stars also affect the parent cloud. In addition, massive stars do not form in isolation but often in clusters and associations. All these factors contribute towards making the study of the formation mechanisms of these systems very difficult. Multiwavelength studies, therefore, hold the potential to probe these complexes at different depths and unravel the least understood aspects of massive star formation.IRAS 06055+2039 (G189.78+0.34, RAFGL 5179) is a massive star-forming region chosen from the catalog of massive young stellar objects by Chan et al. (1996). G189.78+0.34 is listed as an ultracompact (UC) HII region (Shepherd & Churchwell 1996;Bronfman et al. 1996). It belongs to the Gem OB1 molecular cloud complex and is a part of the extended HII region Sh 252. It is associated with S252 A, which is one of the six compact radio sources in Sh 252 revealed...

Sh2-138: physical environment around a small cluster of massive stars

“…Comparable values of α are also found for several star-forming regions like, NGC 1893 cluster (∼ 0.34±0.07, distance ∼3.25 kpc; age ∼1-2 Myr; Sharma et al 2007), and IRAS 06055+2039 cluster (∼0.43±0.09, distance ∼2.6 kpc; age ∼2-3 Myr; Tej et al 2006). The age spread obtained for YSOs in the Sh2-138 region from the V /V − I CM-D is similar to other massive star-forming region and the estimated KLF slope is in agreement with the slopes of several other young clusters.…”

Radio and infrared study of the star-forming region IRAS 20286+4105

“…These colors suggest large NIR excess that possibly indicates a highly extincted protostellar candidate (compare with Figure 7 of Tej et al (2006)). The MIR IRAC colors place it in the location of Class I objects (YSO # 1) in the CC diagrams, consistent with the JHK colors.…”

“…We estimate the extinction by de-reddening the stars using the JHK colour-colour plot (Kumar, Ojha & Davis 2003;Ojha et al 2004). This is done by shifting them along the reddening vector to a line drawn tangential to the turn-off point of the main sequence locus (Tej et al 2006). The estimated values range from Av = 0 to 20 mag and this range is used for the model fitting.…”

“…The values retrieved from the best fitting model is given in parenthesis. 20286+4105 by assuming the radio emission to be free-free from an isothermal, spherically symmetric and homogeneous medium (Tej et al 2006;Vig et al 2014). For this, we convolve the 4.89 GHz and 1280 MHz maps to the resolution of 610 MHz map which has the lowest resolution (7 .26 × 5 .04).…”

Infrared dust bubble CS51 and its interaction with the surrounding interstellar medium

“…The identification and classification of YSOs are carried out using the following procedures. (d) JHKs CCPs have been efficiently used by various authors (Sugitani et al 2002;Ojha et al 2004a,b;Tej et al 2006;Ji et al 2012;Mallick et al 2015) to identify YSOs. The CCP for the NIR sources associated with bubble CS51 is shown in Figure 6(d).…”