Interstellar Gas Clouds And Gen. Ed. Astronomy Students: Who Are They? How Do They Behave?
The first chapter begins with the observations of 1,882 sources from the Bolo- cam Galactic Plane Survey (BGPS) at 1.1 mm in HCO+ J = 3 − 2 and N2H+ J = 3 − 2. We determine kinematic distances for 529 sources and derive the size, mass, and average density for this subset of clumps. The median size of BGPS clumps is 0.75 pc with a median mass of 330 M⊙ (assuming TDust = 20 K). The median HCO+ linewidth is 2.9 km s−1 indicating the clumps are not thermally supported and provide no evidence for a size-linewidth relationship. This collec- tion of objects is a less-biased sample of star-forming regions in the Milky Way that likely span a wide range of evolutionary states.
We study in detail the G111 Infrared Dark Cloud northwest of NGC 7538 with the K-band Focal Plane Array. We map NH3 (1,1) and (2,2), H2O maser, and CCS emission simultaneously with the GBT. We find the NH3 gas traces the 1.1 mm BGPS structure very well with gas kinetic temperatures consistently close to 15 K. Typical column densities are 2.5 × 1014 cm−2 with a median abun- dance of NH3 to H2 of 5.94 × 10−8. The median linewidth of the NH3 emission is 0.64 km s−1indicating the filament is not thermally supported. The NH3 is subthermally populated along the entire filament. Individual NH3 peaks have a median size of 0.61 pc, mass of 188 M⊙, and density of 3.4×103 cm−3. An activity analysis shows the most active star forming regions are found at the junctions of the subfilaments that make up the larger G111 IRDC.
The last chapter describes our systematic examination of individual student responses to the Light and Spectroscopy Concept Inventory national dataset.We use classical test theory to form a framework of results that is used to evaluate item difficulties, item discriminations, and the overall reliability of the LSCI. We perform an analysis of individual student’s normalized gains, providing further insight into the prior results from this data set. This investigation allows us to better understand the efficacy of using the LSCI to measure student achievement.