Future Projects

If you are interested in any of these projects, please feel free to contact me.

The paragraph descriptions are ideas that could be done as summer projects or expanded into 1+ year projects. I have several thesis-scale projects too, such as "reduce and analyze the ALMA-IMF large program", but I haven't gotten around to writing those up. Many of these have been started, but not all!


Software Development Projects

I always have a wide range of software development projects available. If you're interested in working on astro-related tools and techniques, I will have something for you depending on your skill set and interests.

Several project variants are always available:

Line Radiative Transfer Modeling: What effect does turbulence have on observed lines?

Much of what we know of the interstellar medium and of star formation derives from properties we measure using spectral line intensities and line ratios. The standard tools for interpreting lines and line ratios are local thermodynamic equilibrium (LTE) models and large velocity gradient (LVG) models. In both cases, the radiative excitation and transfer is simplified to a one-zone models that reduce the entire line of sight to a single assumed state. This assumption is wrong (e.g., Leroy+ 2017).

To solve this, we will apply radiative transfer models using both LTE and LVG to individual cells in a simulation, but will then do ray-tracing radiative transfer through different viewing angles to see what the effects of varying optical depth and excitation are. This will be done using RADMC-3D, and the initial simulations used will be the CATS database. We will post-process these simulations to produce synthetic line emission maps, and we will analyze them as if the whole simulation box were a single zone. We will derive a mapping from the simulation physical conditions (linewidth, moments of the density, column density, and velocity fields, etc) to line ratios and determine whether they follow a trend that will allow inversion of line ratio to inferred physical properties. This work will also produce, as a side effect, synthetic image for other types of analysis.

Radio Continuum Imaging & Measurement for the ALMA-IMF project

The ALMA-IMF program is a large project to survey to image high-mass star forming regions and count the number of forming new stars of each mass. This measurement of the proto-initial-mass-function (proto-IMF, sometimes core mass function, CMF) is one of the two key ingredients of star formation theory, and if we find environmental variation, it will have profound impact on application of these models in the context of both simulations and extragalactic observations. This sub-project is to measure the "free-free contamination" in our millimeter continuum observations to help get accurate masses toward the highest-mass stars. It will involve imaging radio continuum data from the JVLA, and maybe poking at those same data sets to look for some interesting lines.

Archival Research: Catalog of "core" catalogs

Several surveys of pre- and proto-stellar cores have been created, including dozens of local clouds using single-dish instruments and rapidly growing numbers of Galactic Disk clouds with ALMA. This project will be to assemble a table of these catalogs and determine whether they can be drawn from the same parent distribution, or not. If they cannot, that may indicate that the star formation process differs in these environments. If they can, the data hint at a universal star formation process. The key difficulty in this project is to determine how the catalogs are made and how much of the inevitable differences come from observational effects rather than physical effects.

Salt mining in Chile's high desert

We found salt (NaCl and KCl) in the disks around Orion's Source I and another disk. Are there more salt detections waiting to be extracted from existing data in the ALMA archive? Each detection is likely to result in a dynamical mass measurement of the central source. Together, these detections might tell us more about the physical conditions that allow gas-phase salts to exist around protostars.

Measure the protostellar population in the W51 star forming region: Part II

High-mass star-cluster-forming regions are the most active areas of star formation in the Galaxy and may have been the dominant path for star formation in the early universe. The W51 protocluster region is one of the closest and most massive in our Galaxy. While the high-mass stars have been identified and measured with ALMA and VLA data, there are abundant lower-mass (but still possibly massive) stars in the surroundings that have only recently been discovered with very high resolution data. These objects need to be cataloged, characterized, and described. This detailed characterization will be used as the 'calibration' for our analysis of a large data set in the ALMA-IMF program. We will also look for binaries and attempt to characterize the binary distribution function at our ~300 AU resolution.
Previously, as part of a student project, a cataloging tool was developed and applied to one set of ALMA images. For this project, we need to take these existing catalogs and cross-match them to measure a few key quantities, including the source multiplicity as a function of resolution and source temperature.
This is a follow-up of another project completed by Connor McClellan (U. Florida). Summer Project Repository and associated software package

Ongoing Projects


Which lines trace what processes in the Galactic Center?

UF Graduate Student Alyssa Bulatek is leading this project.
There are a lot of molecular species that trace the entire "Central Molecular Zone" that are not seen in molecular clouds in the solar neighborhood. Some of these, like HNCO and SiO, are typically considered "shock tracers" when observed locally, but they are observed to be ubiquitous in the CMZ, so they're not useful for tracing high-velocity (protostellar jet, for example) material. I have a large ALMA program (not an ALMA large program...) to perform a full spectral line survey of one line of sight through the CMZ that includes diffuse gas, dense gas, molecular cores, and protostellar outflows, and our goal is to determine which molecular species, if any, uniquely trace one of these physical features. Data are being taken in Cycle 7 (Oct. 2019 - Sep. 2020); the Band 3, 4, and 6 components are mostly complete.

Measure the protostellar population in Galactic Center cloud Sgr B2 DS

UF Graduate Student Desmond Jeff is leading this project.
How is star formation in the Galactic center different from the Galactic disk? We have a pretty good idea that it is (see, e.g., Longmore+ 2013 and references thereto), but why? Sgr B2 is the only richly star-forming cloud in the Galactic center, and I have been leading star-counting measurements of its ongoing star formation. In Ginsburg+ 2018, I discovered a large population of protostars that I asserted were all high-mass. About half of them are distributed along an elongated, possibly filamentary string in the "Deep South" subregion of the Sgr B2 molecular cloud. I obtained high-sensitivity and high-resolution data at 1 mm to measure these sources more accurately and search for their purported low-mass counterparts. The data are extremely rich, so there are several projects here:
  1. Catalog the continuum sources at 0.5" and 0.1" resolution. Compare the catalog to the existing 3 mm continuum 0.5" resolution data. Determine what the sources are and whether the IMF extrapolations of Ginsburg+ 2018 were correct. Characterize the source multiplicity on the observed 4000 and 1000 AU scales.
  2. Catalog and measure the outflows in Sgr B2 DS. Quick look imaging revealed at least a dozen SiO J=5-4 bipolar outflows. We need to compare these outflows to Galactic disk and other Galactic center outflows. We will also search for other molecular tracers of outflow within the same data set. We will infer source luminosities and perhaps accretion rates from these measurements.

Measure the Kinematic Structure of Sgr B2, the most massive cloud in our galaxy

UF Undergraduate Madeline Hall is working on this project. Molecular clouds are the regions in which stars form, and they are turbulent. This project aims to measure the kinematic structure (the velocity of difference gas blobs) of the most massive cloud in our Galaxy. The student will use the SCOUSE software to fit spectral profiles to millions of spectra semi-automatically. Because SCOUSE is new and experimental software, this project will involve some software debugging and development. The end result should be an essential measurement of the velocity field and turbulent statistics in a very massive cloud, which will serve as the key measurement in a paper testing theoretical models of star formation. This project will be done in collaboration with Jonny Henshaw, who developed SCOUSE.

Ammonia masers in W51

UF Undergraduate Derod Deal is working on this project.
Ammonia masers are a very rare astronomical phenomenon. They have been detected toward only a handful of sources, including W51 IRS2, in which there are dozens of different masing transitions. I have obtained new high spatial resolution (0.04-0.1 arcsecond, 200-500 AU) data with the VLA with the goal of determining exactly where these masers come from and which source(s) drive them. This project will involve comparison between the VLA data and similar high-resolution data sets from ALMA.

Completed Projects

NRAO REU projects for Summer 2018

Implement a CASA region parser in astropy

Completed by GSoC student Sushobhana Patra. CRTF Documentation
CASA is the main data reduction package for ALMA and VLA data. Regions on the sky such as ellipses, circles, and boxes can be specified in a few different formats. CASA has a region format that is currently supported only by CASA itself, but it will be helpful for researchers to be able to translate these regions to other formats. Astropy is a general-use library for astronomy written in python, and it includes a package for handling sky regions. The student will write a CASA region parser for the astropy regions project. They will gain familiarity both with CASA and astropy. Some experience with python or similar scripted languages is required. This is primarily a software development project and therefore may be of interest to a broader range of students.

Measure the protostellar population in the W51 star forming region

Completed by Connor McClellan (U. Florida). Summer Project Repository and associated software package
High-mass star-cluster-forming regions are the most active areas of star formation in the Galaxy and may have been the dominant path for star formation in the early universe. The W51 protocluster region is one of the closest and most massive in our Galaxy. While the high-mass stars have been identified and measured with ALMA and VLA data, there are abundant lower-mass (but still possibly massive) stars in the surroundings that have only recently been discovered with very high resolution data. These objects need to be cataloged, characterized, and described. The student will examine VLA and ALMA images with resolution ~0.05" and look at source spectra to determine the protostars' luminosities and, ideally, masses. The student will learn to use astropy tools for source finding, Gaussian fitting, and spectroscopic analysis.

Protostars in Orion: Spectral Energy Distributions and proper motions

Completed by Justin Otter (Haverford College). Summer research repository
The Orion nebula is adjacent to the closest high-mass star-forming region in the Galaxy. New ALMA data have revealed several new sources in this region that are likely to be protostars. We would like to measure their positions and luminosities and determine what sorts of protostars they are. Learning about these stars and their motions will tell us what the gravitational potential of the Orion cluster looks like and will be important for determining how high-mass stars have formed there. The student will examine VLA and ALMA images with resolution ~0.05" and look at source spectra to determine the protostars' luminosities and, ideally, masses. The student will learn to use astropy tools for source finding, Gaussian fitting, and spectroscopic analysis. The student will also have opportunities to look at the VLA archive and attempt to reduce archival data if they have the time and ambition.

NRAO REU projects for Summer 2017




Other ideas:

Sgr B2 43 GHz methanol masers: We have VLA A-array (high-resolution) data with dozens of detected methanol masers. We don't know what these masers trace or mean. The data need to be reduced more completely.

Orion disk chemistry: There are ~70 disks in the Orion Source I data set for which we have full spectra, but we haven't analyzed them yet. Are there any lines to be found?


Determine how much mass is ejected in a high-mass outflow

Completed by Terry Melo (Agnes Scott College). Presented at AAS

Goal: Measure the CO/H ratio across a symmetric high-mass outflow. Provide a fundamental calibration for outflow mass-loading rates.

One of the fundamental problems affecting observations of molecular gas is that we don't know precisely how much of each molecule there is relative to the total amount of mass (or the total amount of hydrogen, since it's mostly hydrogen). This outflow, known as the "Lacy Jet" for its discoverer, is unique in that it is (almost) perfectly symmetric, but one half is molecular and the other half is ionized. Because we can measure the hydrogen mass directly in an ionized medium, we should be able to measure the CO abundance directly in this outflow. The project should involve a relatively straightforward measurement followed by an examination of the possible confusing effects that might impact the measurement.

The student will learn about molecular abundances and protostellar outflows. They will be trained to use interpolation and reprojection algorithms to match datasets on different grids. The project is based on data from ALMA, the VLA, and the IRTF.




Geometry of Molecular Clouds in the CMZ

Part of Natalie Butterfield's PhD thesis (U. Iowa)

Goal: Determine the geometry of the clouds using the method demonstrated in Ginsburg+ 2015 (fig 9) and figure out how far the clouds are from the central black hole.

While improved models of the CMZ's geometry have recently been developed (1,2), we still know little about where exactly the clouds are relative to the central black hole and one another. This geometric information is crucial for understanding the physical properties and evolutionary sequence of clouds in the CMZ.

The basic method is to compare H2CO absorption with 13CO emission in position-velocity cubes over regions where we know that HII regions are present in the CMZ along the line of sight. By comparing the emission and absorption, we can determine which clouds are in the foreground or background of the HII regions and therefore where along the "CMZ Ring" they lay.

This project will use ATCA, GBT, and VLA data sets that are already reduced. The analysis will be primarily visual, using ds9 and glue to compare the images. The student will learn these visualization tools and the details of the CMZ's layout.