PMS stellar objects are identified in a cluster located in the vicinity of IRAS 05137+3919 using the UKIDSS data base and Spitzer telescope (IRAC) images. The age of the cluster is 1.5-2.0 million years.Young stars are distributed nonuniformly in the cluster and form two subgroups. One is localized around the YSO CPM, which is a binary star, and the second contains a substantial number of objects with early spectral classes surrounded by gas-dust nebulae. The K luminosity functions of the PMS stars indicate that the cluster is at a distance of ~4.5 kpc. One of the components of CPM 15 appears to have Sp B3-B5 and is an Ae/Be Herbig star.

IRAS 18507+0121, IRAS 20188+3928, IRAS 20198+3716) the compact groups

Aims. We report the investigation results of the structure and content of a molecular cloud surrounding the source IRAS 05168+3634 (also known as Mol 9). Methods. We present a photometric analysis using the data of J, H, K UKIDSS, [3.6], [4.5] µm S pitzer-IRAC and 3.4, 4.6, 12, 22 µm WISE databases. A multi-color criteria was used to identify the candidates of young stellar objects (YSOs) in the molecular cloud; in addition to IRAS 05168+3634, there are four IRAS sources embedded in the same molecular cloud. Color-magnitude diagrams and the K luminosity function (KLF) were used to determine the basic parameters of stellar objects (spectral classes, masses, ages). To study the YSOs with longer wavelength photometry the radiative transfer models were used. Results. Based on color-color and color-magnitude diagrams, we identified a rich population of embedded YSO candidates with infrared excess (Class 0/I and Class II) and their characteristics in a quite large molecular cloud located in a region of 24 arcmin radius. The molecular cloud includes 240 candidates of YSOs within the radii of subregions around five IRAS sources. The local distribution of identified YSOs in the molecular cloud frequently shows elongation and subclustering. The observed young subregions and parental molecular cloud morphologies are similar, especially when only the youngest Class I/0 sources are considered. The colormagnitude diagrams of the subregions suggest a very young stellar population. We construct the KLF of the subregions except for the IRAS 05162+3639 region) and it shows unusually low values for α slope: 0.12-0.21. According to the values of the slopes of the KLFs, the age of the subregions can be estimated at 0.1-3 Myr. The spectral energy distributions (SEDs) are constructed for 45 Class I and 75 Class II evolutionary stage YSOs and the received parameters of these YSOs are well correlated with the results obtained by other methods.

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( $\mathrm{H}_2$ )) and dust temperature ( $T_d$ ) in the molecular cloud using Modified blackbody fitting on Herschel images obtained in four bands: 160, 250, 350, and $500\,\unicode{x03BC}\mathrm{m}$ . 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( $\mathrm{H}_2$ ) varies from ${\sim}3.0 \times 10^{23}$ to $5.5 \times 10^{23}\,\mathrm{cm}^{-2}$ within the G45.07+0.13 and G45.12+0.13 regions, respectively. The maximum $T_d$ value is 35 K in G45.12+0.13 and 42 K in G45.07+0.13. $T_d$ then drops significantly from the centre to the periphery, reaching about 18–20 K at distances of ${\sim}2.6$ and ${\sim}3.7\,\mathrm{pc}$ 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 ${\sim}3.4 \times 10^5\,\mathrm{M}_\odot$ and ${\sim}1.7 \times 10^5\,\mathrm{M}_\odot$ in G45.07+0.13. The UC HII regions are connected through a cold ( $T_d = 19\,\mathrm{K}$ ) 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 $10^6$ yr. 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, $\beta \sim 2$ ) at 1 Myr. The non-cluster objects are uniformly distributed in the molecular cloud, 80% of which are located to the right of the 0.1 Myr isochrone. The slope $\alpha$ of the KLF of non-cluster objects is $0.55\,\pm\,0.09$ , corresponding better to a Salpeter-type IMF for low-mass objects (G–M stars, $\beta \sim 1$ ). 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.

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