Abstract Details
| Name: Somnath Dutta Affiliation: SNBNCBS, Kolkata Conference ID: ASI2019_446 Title : MULTI-WAVELENGTH STUDIES ON GALACTIC H II REGIONS Authors and Co-Authors : Somnath Dutta Abstract Type : Oral Abstract Category : Thesis Abstract : The formation of a star cluster is a topic of considerable interest since most stars in our Galaxy form in clusters. Several environmental conditions can breed young clusters such as: fragmentation of the swept up matter in the shells of the expanding H II regions, external compression of pre-existing clumps by nearby massive stars, matter sandwiched between bubbles, at the collision point of molecular clouds and at the junction of converging filaments or hub of filamentary systems. With an objective to understand better the star formation, I have investigated star formation activities of three distant star-forming regions e.g., PGCC G108.37-01.06 (hereafter, PG108.3), NGC 2282 & Cygnus OB7 (CygOB7) using multiwavelength data. The IPHAS images reveal H-alpha emission at various locations around our target, and optical spectroscopy at 2m HCT of the bright sources in those zones of H-alpha emission disclose massive ionizing sources. Based on the stellar surface density map constructed from the deep near-infrared (NIR) CHFT or UKIDSS observations, we find prominent star clusters in those molecular clouds. Using IR colour-colour criteria and H-alpha emission properties, we have identified the candidate YSOs in the region, which include the Class II, Class I YSOs. Our I-band time-series photometry at 2m HCT and 1.3m DFOT of two young clusters NGC 2282 and CygOB7 reveals that 50-65% of the variable stars are Pre-Main Sequence and candidate members of the cluster. A careful inspection of JCMT CO molecular data exhibits that the massive cluster is associated with a number of filamentary structures. Based on the distribution of ionized, molecular gas and young stellar objects (YSOs), we suggest the cluster formation (particularly in PG108.3) is primarily due to filamentary inflows to a hub potential system. However, our observational evidence does not favour any feedback from massive stars to the next generation star formation. |