Savin Group

This is the wiki for Daniel Wolf Savin's group at the Columbia Astrophysics Laboratory. His homepage is ​here.

Projects

The Molecular Processes which led to the Formation of the First Stars

Using self merged beams of H and H- we are mimicking the process that formed H₂ in the early universe. Photon emission from H₂ allowed primordial clouds to cool and for protogalaxies and stars to form out of these clouds sort of like water droplets in a cloud on a foggy day.

Chemical reaction rates and cross sections for associative detachment

• Hydrogen Data

Art Inspired by the Science

Our research not only advances science but also serves as a muse for art. Check out the site ​Star Womb site to see how.

The Cosmic Origins of Organic Chemistry

Using a novel apparatus to merge beams of atomic carbon and molecular ions we will be investigating the reactions in molecular clouds which lead to the formation organic molecules from the most basic to increasing degrees of complexity.

Atomic Processes in Winds from Supermassive Black Holes

Recent X-ray satellite spectroscopic observations by Chandra and XMM-Newton of active galactic nuclei (AGNs) have detected a previously unobserved set of spectral features. These features are attributed to the winds emanating from the super-massive black hole lurking in the center of each AGN. However, our ability to reliably interpret these features and infer the properties of this wind and the embedded black hole is limited by uncertainties in our understanding of the atomic physics which produces the observed spectrum. Especially important is determining correctly the ionization structure of the gas. This in turn depends on understanding the electron-ion recombination process known as dielectronic recombination (DR) at low electron temperatures.

Characterizing the origins of the solar wind

Investigating the dynamics of the solar corona is crucial if one is to understand fundamental solar and heliospheric physics. The corona also greatly influences the Sun-Earth interaction as it is from here that the solar wind originates. The solar wind can have a profound effect on the Earth's magnetosphere and ionosphere, disrupting power grids and communication. Hence characterizing the origins of the solar wind is of obvious importance. This is done, in part, through a combination of solar spectroscopic observation, spectral analysis codes, and theoretical models for the transport of energy and particles from the photosphere through the corona and into the solar wind. Recently we have developed a new approach for analyzing solar spectra which yields more reliable determinations for the relative elemental abundances in the corona. We are also carrying out a series of high temperature DR and electron impact ionization (EII) measurements so that we can generate more accurate ionization balance calculations of the corona and thereby better spectral models.

Atomic data and ionization balance calculations

• Dielectronic recombination data
• Electron impact ionization data
• Collisional ionization equilibrium model

The collisional ionization equilibrium (CIE) project provides ionic fractional abundances in a zero-density collisional plasma for all elements from H through Zn.

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