Investigating the Early Stages of Massive Star Formation in Protocluster Environments: Multiwavelength Studies of Extended Green Objects
Massive Young Stellar Objects (MYSOs) are not found in isolation, but rather have a predilection for forming in clustered environments with other protostars. Therefore, the study of MYSOs necessarily requires the study of proto-clusters as a whole. Extended Green Objects (EGOs) are massive young protoclusters believed to be in an evolutionary state just prior to the emergence of UC HII regions - a phase which is critical for distinguishing between competing theories of massive star formation.
We have investigated the physical and kinematical properties of massive star forming regions at various evolutionary stages via near-infrared to centimeter observations. We first explore the initial conditions of the massive star formation by examining the properties of infrared dark clouds (IRDCs) and their natal Giant Molecular Clouds (GMCs). This study shows the observational evidences of grain growth for the first time in such extreme environments with the mid- to far-infrared data. We also show the potential importance of turbulence and magnetic field to form IRDCs.
Dust and gas play key roles in obscuration and supplying the supermassive black holes (SMBH) in active galactic nuclei (AGN). Nuclear observations of AGN have historically attributed mid-IR emission primarily to an obscuring parsec-scale dust torus coplanar to the equatorial accretion disk. However, recent studies have found that a majority (>50%) of nuclear MIR emission is due to an extended radiation-driven dusty wind in the polar region of some nuclei, possibly extending out to hundred-parsec scales. An additional source of MIR emission on this scale is due to star formation. With
Kelly Latimer, Virgin Orbit’s chief pilot, along with her Flight Test Director, Zack Rubin, will give a talk about the exciting development and challenges to launching a rocket from a plane. Virgin Orbit is part of the larger Virgin Group and a sister company to Virgin Galactic. Virgin Orbit is getting ready to conduct its debut launch in the coming months.
The study of extended, cold dust envelopes surrounding R Coronae Borealis (RCB) stars began with their discovery by IRAS. RCB stars are carbon-rich supergiants characterized by their extreme hydrogen deficiency and for their irregular and spectacular declines in brightness. I have examined new and archival Spitzer Space Telescope and Herschel Space Observatory images in the far infrared and submillimeter of these envelopes to examine the morphology of these dusty shells.
The ISM in the inner few hundred pc of the Galactic center differs from elsewhere in the Galaxy. This region is centered on a 4 million supermassive black hole and is occupied by a large concentration of molecular gas with high column density, high velocity dispersion and high gas temperature. Recent IR and X-ray observations indicate that the cosmic ray ionization rate is higher than elsewhere in the Galaxy by one to two orders of magnitudes.
The unidentified infrared bands (UIR) bands have been observed ubiquitously in various astrophysical environments. Polycyclic aromatic hydrocarbon (PAH) hypothesis is commonly used to interpret the behavior of the observed UIR bands, however, our knowledge on the true carriers of the UIR bands is still limited. We have synthesized Nitrogen-included Carbonaceous Compounds (NCC) by exposing hydrocarbons (e.g., Quenched Carbonaceous Composite; QCC and/or PAHs) to nitrogen plasma via 2.45 GHz microwave discharge.
Astronomy at far-infrared and submillimeter wavelengths offers a unique window to study the physical properties of a wide variety of interstellar environments, ranging from the stellar nurseries in our Galaxy to the relativistic jets of faraway blazars. Polarimetric observations in particular can probe the magnetic and turbulent properties of these environments, providing insights into notoriously challenging topics such as the role of magnetic fields in the formation of stars and their planets.
SAMI and friends: advancements in multi-object integral-field spectroscopy and other novel astrophotonic developments
Traditionally there are two ways to obtain galaxy spectra with optical fibres: (a) 1000 fibres on 1000 galaxies (b) 1000 fibres on 1 galaxy. The former lacks spatial information, and the latter lacks sample sizes. This decade has seen the development of new instruments that go for the middle ground: 10 fibre bundles of 100 fibres each on 10 galaxies, providing spatial spectroscopy on large samples of near-by galaxies.