Giant HI shells, with diameters of hundreds of parsecs and expansion velocities of 10-20 s−1 are characteristic observed features of local gas rich galaxies. Although a predictable consequence of the impact of OB associations on the ISM doubts have been raised, as OB stars are not present in the centres of the majority of these shells. Here we combine our observations of expanding ionized shells in luminous H II regions with basic dynamical models to give support to the scenario in which OB associations do produce the HI shells.

Disks of galaxies in clusters are deeply affected by interactions. We investigate the pattern speed of galaxies in cluster in order to detect a possible dependence with cluster environmental parameters, such as galaxies density. If the perturbation of cluster galaxies is mainly produced by the interaction with the cluster ambient, the pattern speed might well depend on the history of the galaxy orbit within the cluster. Tremaine & Weinberg (1984) method is applied to 2-D Hα velocity fields, reconstructed from the isovelocity contours published by Amram et al. (1992), and 2-MASS K–band images (Skrutskie 2001) to obtain spirals pattern angular speed. The use of K–band images and Hα velocity maps is justified by the fact that the perturbations imprinted in Hα velocity maps are produced by the old stellar population which emits most of its energy in the near-IR. We analyzed Pegasus I cluster galaxies NGC 7593, NGC 7631 and NGC 7643 (this one shown in Figure 1). Preliminary results indicates that NGC 7593 presents a pattern speed Ωp sin(i) = 18 ± 5km s−1 kpc−1, (inclination i = 51°) while NGC 7631 and NGC 7643 pattern speeds are Ωp sin(i) = 21 ± 4 km s−1 kpc−1 and Ωp sin(i) = 35 ± 3 km s−1 kpc−1 (inclinations i = 64° and 59° respectively). In the three successful cases the correlation coefficients in the 〈X〉 vs 〈V〉 plots are 0.94, 0.95 and 0.98 respectively. We are presently analyzing other galaxies in the cluster.

The far-ultra violet (6 – 13.6 eV) photons from the OB stars in Ultra-compact HII regions (UCHs) produce photo-dissociation regions (PDRs) at the interface between the ionized and the natal molecular material. In this paper, we show that carbon recombination lines (CRLs) at frequencies greater than a few GHz are detectable from these PDRs and such observations can be used to: (1) estimate the physical properties of the PDR material; (2) study the kinematics of the PDR material relative to the HII region gas; (3) constrain the magnetic fields in the vicinity of UCHs and (4) address the lifetime problem of UCHs.

The Virgo Cluster spiral NGC 4569 is known for its compact starburst in the core and unusual outflow of Hα emitting gas perpendicular to the galaxy disk. Recent radio polarimetric observations with the Effelsberg telescope reveal huge magnetized outflows. Preliminary results of our XMM-Newton observations uncover not only hot gas in the disk but also an extensive X-ray envelope around it. We investigate the possibility of starburst-induced galactic outflows in various gas phases and cluster influence on the galaxy evolution.

We have found massive clumps without any sign of active star formation in the AFGL 333 cloud. We present a study of the physical and chemical properties of the AFGL 333 cloud.

We report the preliminary results of the study on the infrared properties of ultracompact (UC) H II regions in our Galaxy and in the Large Magellanic Cloud (LMC) based on the GLIMPSE (the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire) and SAGE (Surveying the Agents of a Galaxy's Evolution) data, respectively. We found that ~60% of the Galactic UC H II regions do not have IR counterparts. Large extinction and very strong stellar winds evacuating H II regions from dust may explain this result. The same effect is observed in the LMC. One of the goals of this research is to develop a means of identifying UC H IIs based on their mid-IR properties, e.g. positions on color-color and color-magnitude plots and/or shape of spectral energy distributions. GLIMPSE showed that bow shocks, protostellar jets/outflows, and bubbles are common phenomena in massive star formation regions (MSFRs).

Studying the chemical compositions and color-magnitude diagrams of globular clusters in the nearby low-mass galaxies is critical to compare properties of these long-living objects situated in galaxies of different type and mass, and to establish the role of dwarf galaxies as building blocks of massive early-type and spiral galaxies. We present measurements of ages, metallicities and [α/Fe] ratios for 16 globular clusters (GC) in NGC147, NGC185, and NGC205 and for the central regions of the diffuse galaxy light in NGC185, and NGC205, based on measurements of absorption line indices as defined by the Lick standard system in spectra obtained with the SCORPIO multi-slit spectrograph at the 6-m telescope of the Russian Academy of Sciences. We include in our analysis high-quality HST/WFPC2 photometry of individual stars in the GGs to investigate the influence of their horizontal branch (HB) morphology on the spectroscopic analysis. The HB morphologies for our sample GCs follow the same behavior with metallicity as younger halo Galactic globular clusters. We show that it is unlikely that they bias our spectroscopic age estimates based on Balmer absorption-line indices. Almost all our sample GCs appear to be old (T > 8 Gyr) and metal-poor ([Z/H]<−1.1). We find that most of the GCs in the studied galaxies are weakly or not α-enhanced, in contrast to the population of GCs in nearby early-type galaxies, and to the halo population of GCs in M31 and Milky Way.

We investigate the formation of clouds and substructure in spiral galaxies using high resolution global MHD simulations, including gas self gravity. Previously, local modeling by Kim & Ostriker (2002) has shown that self gravity and magnetic fields cause the growth of high density clumps in the spiral arms rather rapidly; subsequently, these clumps result in the formation of sheared, feather like structures in the interarms, known as spurs. Recently, we performed global simulations and found that gas self-gravity can cause the growth of sheared features regardless of the strength of the external spiral potential. However, a sufficiently strong spiral potential is required to produce arm clouds as well as spurs, which are the filamentary structures distinctly associated with the spiral arms, having near-perpendicular intersections with the main dust lane. We are currently performing higher resolution simulations to study the detailed properties of the clouds and spurs; we are also including a feedback mechanism, representing turbulent forcing via supernovae, to destroy the clouds. We will thus assess the role of turbulence on the clump formation rate and properties. Further, we will also follow how subsequent arm and spur morphology develops under quasi-steady conditions.

Since most stars are born as members of clusters (Lada & Lada 2003), it is important to clarified the detailed mechanism of cluster formation for comprehensive understanding of star formation. However, our current understanding of cluster formation is limited due to the followings;

1. (a) Cluster forming regions are located at the far distance.

2. (b) There are complex mixtures of outflows and dense gas in cluster forming regions.

From results of the 12CO(J=1-0) outflow, H13CO+ dense gas, and the SiO shock, the outflow from FIR 3 interacts with dense gas in the FIR 4 region. Moreover the Position-Velocity diagram along the major axis of the 12CO(J=3-2) outflow shows that the 12CO(J=1-0) and SiO emission exhibits a L shape (the line widths increase in the interacting region in morphology). This is an evidence of interaction between the outflows and dense gas (Takakuwa et al. 2003). From result of the 3 mm dust continuum, the interacted region by the molecular outflow of FIR 3 is an assemble of seven dense cores. The mass of each core is 0.1-0.8 M. This clumpy structure is evident only at FIR 4 in the entire OMC-2/3 region. There are possible that two cores are in the proto-stellar phase, because 3 mm dust continuum source correspond to NIR source or 3.6 cm f-f jet source. From these results, cores in the FIR 4 region may be potential source of the next-generation stars. In the other words, there is a possibility that the molecular outflow ejected from FIR 3 is triggering the cluster formation in the FIR 4 region.

We explore the physical characteristics of young stellar clusters in the Antennae by combining recent ground- and space-based mid-infrared observations with a newly developed set of diagnostic diagrams. Spitzer data give an overview of the star-forming regions extending over hundreds of parsecs, showing a dominant diffuse ISM component with a density of 102 cm−3 plus a small fraction of very compact material (106 cm−3). With its higher spatial resolution VISIR gives a close-up view of the latter component. Its emission line ratios suggest that these regions are fundamentally different from local star-forming regions. Instead of having small isolated UCHII regions, as in local star-forming regions, the average density of the medium of the whole region falls in the (ultra)compact regime, exceeding 104 cm−3 over tens of parsecs.

We present fine structure line of neutral carbon at 492 GHz (3P1–3P0, hereafter [C I] 1–0) and 12CO 4–3 KOSMA observations. This data has been combined with FCRAO 12CO 1–0 and 13CO 1–0 data. We have used these observations to understand the emission from the photon dominated regions (PRDs) in IC 348. We confirm the anti-correlation between N(C)/N(CO) and N(H2) as seen in most Galactic PDRs (Mookerjea et al. 2006).

External shock triggering and internal turbulence play major role for the condensation of the ISM and star formation. Some evidences of shock triggering by non-isotropic compression are seen in the cloud morphologies and associated active cluster formation such as the ρ Oph and Cha I clouds. Surveys for C18O dense cores have shown that internal turbulence dominates the core dynamics and regulates star formation activity (Tachihara et al. 2002).

We have newly performed millimeter- and submillimeter-wave observations in the nearest GMC: the Orion Molecular Cloud -2/3 region (OMC-2/3). Here, we report results of our large-scale (22' × 14') outflow survey with the Atacama Submillimeter Telescope Experiment (ASTE) in the CO(3-2) emission. The OMC-2/3 region is one of the famous intermediate-mass star-forming regions and harbors several sources diagnosed as Class0 protostars (Chini et al. 1997). With the intensive ASTE observations, we totally identified the 8 clear, 5 probable and 6 marginal outflows in OMC-2/3. 8 clear outflows from them, MMS 2, MMS 5, MMS7, MMS9, FIR-2, FIR 3, VLA 13, and FIR 6b are associated with mm and SPITZER 24 μm sources. The others are more or less complicated, and two of which, VLA 13 and FIR 6, are newly identified. We found the interaction between the molecular outflows and the dust condensations at least in four regions. In addition, we confirmed the increment of the velocity width of the dense gas toward some of these condensations (i.e. at the termination of the outflow lobes). These results suggest that (i) the interaction between the outflows and the dense condensation occurs commonly in the OMC-2/3 region, (ii) the dense condensations in this region are compressed ubiquitously by these outflows and are receiving a part of the momentum from them. Particularly, one of the strongest millimeter sources, and hence protostar candidates, FIR4, is strongly compressed by a molecular outflow driven by FIR3 located at the north-east of FIR 4. These results suggest that the molecular outflows play an important role in the formation and evolution of stars and that the outflows are a driving mechanism of turbulence in the OMC-2/3 region.

We studied the stability properties of isolated star forming dwarf galaxies with the aim to identify star burst modes. The impact of the stellar birth function (parametrization, IMF), the stellar feedback and the ISM model on the galactic star formation history was investigated. We focussed especially on dynamically driven star bursts induced by stellar feedback. We applied a one-zone model for a star-gas system coupled by both mass and energy transfer. Additionally, we extended the classical closed box network for active dynamical evolution (Theis 2004). This allows for a simple, but consistent description of the coupling between the dynamical state of a galaxy and its internal properties like star formation activity or the thermal state of the interstellar medium.

As young stars form, they interact with their environment in many ways. We study the radiative interaction of a young star with its surrounding cluster environment. The change in gas temperature caused by a forming star can trigger the formation or inhibit the growth of nearby star forming cores. We calculate the gas temperature around a single star by balancing the dust-gas collisional heating, molecular cooling, and cosmic ray heating rates for a grid of models with various luminosities and density distributions. In the future, this work can be used in large-scale simulations of clustered star formation to study the effect of using a gas temperature which depends not only on density, but also on radiative environment.

The Red MSX Source (RMS) survey (Hoare et al. 2005) is a multi-wavelength programme of follow-up observations designed to distinguish between genuine massive young stellar objects (MYSOs) and other embedded or dusty objects, such as ultra compact (UC) HII regions, evolved stars and planetary nebulae (PNe). We have identified nearly 2000 MYSOs candidates by comparing the colours of MSX and 2MASS point sources to those of known MYSOs. There are several other types of embedded or dust enshrouded objects that have similar colours as MYSOs and contaminate our sample. Two sources of contamination are from UCHII regions and PNe, both of which can be identified from the radio emission emitted by their ionised nebulae. In order to identify UCHII regions and PNe that contaminate our sample we have conducted high resolution radio continuum observations at 3.6 and 6 cm of all southern MYSOs candidates (235° < l < 350°) using the Australia Telescope Compact Array (ATCA).

We present the results of a multi-wavelength line and continuum study of the bright-rimmed cloud SFO 75 in an attempt to determine whether the ionisation front and its associated shocks, driven by the nearby O star, have triggered the formation of a new generation of stars within this bright-rimmed cloud.

We present preliminary results of a Fourier transform power spectra analysis carried out on a sample of dwarf irregular galaxies and Local Group members. This project is intended to study turbulence and the ISM structure in irregulars as a class.

We study the star formation history of the galactic young open cluster NGC 6231 using new, deep, wide-field BVRI imaging. Contrary to previous suggestions, we do not find a lack of low-mass cluster members; our derived mass function is compatible with a Salpeter IMF. The star formation history of NGC 6231 appears to be bi-modal, with a first wave of star formation activity 3–5 Myr ago, followed by a new generation of stars forming ~ 1 Myr ago.

By using 2D simulations, we examine the generation of dense cores and substructures by magnetosonic waves. We find that the excitation of slow-mode waves by fast-mode waves produces these high-density structures.