Star formation rates in galaxies are frequently estimated using the Balmer line fluxes of their H II regions. However, these can be systematically underestimated because dust competes for the absorption of Lyman continuum photons in the ionized gas. This factor cannot be neglected, and in this paper we present theoretical correction factors in a simple analytic form in order to allow observers ...

We report on the properties of electric fields generated as a result of electron irradiation of dielectrics in a low vacuum scanning electron microscope. Individual field components produced by ~i! ionized gas molecules located outside the sample surface and ~ii! subsurface trapped charge were detected by measurements of changes in ~i! primary electron landing energy and ~ii! secondary electron...

There are many advantages to miniaturizing systems for chemical and biological analysis. Recent interest in this area has led to the cre ation of several research programs, including a Micro Gas Analyzer (MGA) project at MIT. The goal of this project is to develop an inexpensive, portable, real-time, and low-power approach for detect ing chemical and biological agents. Elements entering the MGA...

Understanding the interaction between a weakly ionized gas and a shock wave is important for detailed knowledge of the conditions of planetary atmospheric entry. This interaction can manifest itself in the form of a localized increase of electron temperature, plasma induced shock dispersion and acceleration, optical emission enhancement, or double electric layers. In our work, a microwave disch...

The Directional Recoil Identification From Tracks (DRIFT) detector has recently been proposed [?] to search for dark matter. This detector is unique in that it drifts negative ions, instead of electrons, in a time projection chamber (TPC). A detailed description of the operation, motivation, and other uses of a negative ion TPC (NITPC) can be found in [?]. Briefly, an electronegative component ...

We present initial results from a new 440-ks Chandra HETG GTO observation of the canonical Seyfert 2 galaxy NGC 1068. The proximity of NGC 1068, together with Chandra’s superb spatial and spectral resolution, allow an unprecedented view of its nucleus and circumnuclear NLR. We perform the first spatially resolved high-resolution X-ray spectroscopy of the ‘ionization cone’ in any AGN, and use th...

The contribution of free-free and recombination radiation to the IR emission from regions of massive star formation is investigated. A method for calculating Gaunt factors for free-free emission from a hydrogenic non-relativistic gas is employed and the results are compared with approximation formula from the literature. While the cooling of ionized star forming regions due to free-free and fre...

We investigate the dissipation of magnetic flux in primordial star-forming clouds throughout their collapse including the run-away collapse phase as well as the accretion phase. We solve the energy equation and the non-equilibrium chemical reactions in the collapsing gas, in order to obtain the radial distribution of the ionized fraction during the collapse. As a result, we find the ionized fra...

The properties of starbursts in ultraluminous infrared galaxies are discussed, with particular emphasis on the fueling, the amount of extinction and the intrinsic properties of the nuclear starbursts. It is shown by the example of NGC6240 that the H2 vibrational lines can be used to measure the rate of gas inflow into the potential well, which is sufficient to fuel a nuclear starburst of the in...

We present an analysis of wind-blown, parsec-sized, mid-infrared bubbles and associated star formation using the GLIMPSE IRAC, MIPSGAL MIPS, and MAGPIS VLA surveys. Three bubbles from the Churchwell et al. catalog were selected. The relative distribution of the ionized gas (based on 20 cm emission), PAH emission (based on 8 m, 5.8 m, and lack of 4.5 m emission), and hot dust (24 m emission) is ...