Ultra-compact H II (UC HII) regions are an important phase in the formation and early evolution of massive stars and a key component of the interstellar medium (ISM). The main objectives of this work are to study the young stellar population associated with the G45.07+0.13 and G45.12+0.13 UC HII regions, as well as the ISM in which they are embedded. We determined the distribution of the hydrogen column density (N(H_2_)) and dust temperature (T_d_) in the molecular cloud using Modified blackbody fitting on Herschel images obtained in four bands: 160, 250, 350, and 500um. We used near-, mid-, and far-infrared photometric data to identify and classify the young stellar objects (YSOs). Their main parameters were determined by the radiation transfer models. We also constructed a colour-magnitude diagram and K luminosity functions (KLFs) to compare the parameters of stellar objects with the results of the radiative transfer models. We found that N(H_2_) varies from ~3.0x10^23^ to 5.5x10^23^cm^-2^ within the G45.07+0.13 and G45.12+0.13 regions, respectively. The maximum T_d_ value is 35K in G45.12+0.13 and 42K in G45.07+0.13. T_d_ then drops significantly from the centre to the periphery, reaching about 18-20K at distances of ~2.6 and ~3.7pc from InfraRed Astronomical Satellite (IRAS) 19110+1045 (G45.07+0.13) and IRAS 19111+1048 (G45.12+0.13), respectively. The gas plus dust mass value included in G45.12+0.13 is ~3.4x10^5^M_{sun} and ~1.7x10^5^M{sun} in G45.07+0.13. The UC HII regions are connected through a cold (T_d=19K) bridge. The radial surface density distribution of the identified 518 YSOs exhibits dense clusters in the vicinity of both IRAS sources. The parameters of YSOs in the IRAS clusters (124 objects) and 394 non-cluster objects surrounding them show some differences. About 75% of the YSOs belonging to the IRAS clusters have an evolutionary age greater than 106yr. Their slope {alpha} of the KLF agrees well with a Salpeter-type initial mass function (IMF) ({gamma}=1.35) for a high mass range (O-F stars, {beta}~2) at 1Myr. The non-cluster objects are uniformly distributed in the molecular cloud, 80% of which are located to the right of the 0.1Myr isochrone. The slope {alpha} of the KLF of non-cluster objects is 0.55+/-0.09 , corresponding better to a Salpeter-type IMF for low-mass objects (G-M stars, {beta}~1). Our results show that two dense stellar clusters are embedded in these two physically connected UC HII regions. The clusters include several high- and intermediate-mass zero-age main sequence stellar objects. Based on the small age spread of the stellar objects, we suggest that the clusters originate from a single triggering shock. The extended emission observed in both UC HII regions is likely due to the stellar clusters.

Cone search capability for table J/other/PASA/39.24/nir (NIR photometric data of selected YSOs)

Cone search capability for table J/other/PASA/39.24/fir (FIR photometric data of selected YSOs)