Kevin Volk

CSA NIRISS Support Astronomer
Space Telescope Science Institute

3700 San Martin Drive
Baltimore, MD 21218 USA
Phone: 410-338-4409
Fax: 410-338-4211
E-mail: volk AT stsci.edu
Web: www.stsci.edu/~volk

Current Position

I am working at STScI in Baltimore as a support astronomer for the Near-Infrared Imager and Slitless Spectrograph/Fine Guidance Sensor, which is part of the James Webb Space Telescope mission. The instrument was built by the Canadian Space Agency. As part of this effort my position at STScI is supported from Canada. The NIRISS instrument was previously the Tunable Filter Imager (TFI).

Before moving to Baltimore in the spring of 2009 I had spent 6 years at Gemini Observatory , mostly supporting the mid-infrared instruments Michelle and T-ReCS. Switching to support of the NIRISS instrument, which is completely different in design and wavelength range than the thermal infrared astronomy I was used to, was quite a big change in duties. So now I know a lot more about HgCdTe detectors and grisms than I did before I started here. In many ways I find calibration more interesting than doing science.

Since late March 2014 I have been resident in Alberta, Canada, while still working at STScI. Thanks to the internet and teleworking initiatives I am able to carry out my work while only being physically present at STScI part of the time. I am grateful to the people at CSA, HIA, and STScI who have supported my relocation back to Canada from the United States while allowing me to continue working on the project.

What is a "Support Astronomer" anyway?

My main focus is calibration of NIRISS. There was much work on this in JWST commissioning, but even that was just the minimum to get things started. Now that JWST is operational we will be refining the basic calibration over time. Right now my work is along the following lines:

doing analysis of the NIRISS commissioning data and whatever observations are being taken in normal operations to better understand the instrument response, look for any potential problems, and so on;
looking at the way the JWST data reduction pipeline performs with real data, and refining the algorithms in response;
producing initial versions of the calibration files needed for data reduction from the on-orbit data (on-going work from commissioning);
writing the inevitable reports about what happened in commissioning;
pending work...looking at the cross-instrument calibration of JWST in the hope that imaging using NIRISS is consistent with imaging using NIRCam, and that spectroscopy using NIRISS is consistent with spectroscopy using NIRSpec; if not, then we need to understand what the systematic differences are between the various instruments.

The JWST data volume mounts up rather quickly, so I have several TBytes of on-orbit data on disk just from the commissioning work for NIRISS.

Useful Links

A magnitude/flux density conversion utility, kindly hosted by Geoff Clayton of Louisiana State University. This used to be on my Gemini pages, but those disappeared some 4 years after I left Gemini. Unfortunately I cannot host the page at STScI. If that link is down, another copy can be found here, this one being hosted by Colin Aspin of the University of Hawaii.
The Astronomy Picture of the Day
AAS Homepage (with access to the AAS Job Register)
ADS Abstract Service
SIMBAD Astronomical Database
The Official U.S. Time page in case you want to know the exact time

Research Interests

Over the years I have gotten more interested in calibration than in the research end of things, in part because there is far more work in the calibration end of things than I have time to do, let alone finding time for science. However I still try to keep an eye on work concerning the following topics:

Dust around evolved stars
Planetary Nebulae and ionized nebulae in general
"Proto-Planetary Nebulae": stars evolving from the asymptotic giant branch phase to the planetary nebula phase of evolution

Research Collaborators

My research (in the rare cases when I find time to do such currently) is done in cooperation with various people including:

Publication List

A listing of all my bibliographic references from the ADS Abstract Service can be found in this text file. The file was produced by exporting a search for "K. Volk" in the ADS site and then removing the papers by Karen Volk, Klaus Volk, Kathryn Volk, and Katharina Volk from the list by hand. Sometime in the last 5 years the output format from ADS has changed such that I cannot seem to export the information in html format. This is the result of exporting in the "ADS" format. There are currently 285 entries of which 138 are refereed papers. Of the latter group I am first author on 22 papers if I counted them correctly. Most of the recent publications listed are of course JWST-related instrument papers. This listing is more a matter of curiousity for me than being actually required for anything these days as my astronomy career is approaching its twilight.

One sees the tendency for more and more co-authors in the listed papers as time goes on. The Rigby et al. (2022) paper has 611 authors. Granted that is a bit of an unusual case. Still, it is rare that single author papers come out these days as opposed to when I started in astronomy.

Review of the 21 micron Feature and the 30 micron Feature

At the request of Sun Kwok I lead a review paper about the 21 micron feature seen in a small number of post-AGB stars and about the 30 micron feature seen in carbon stars which was published a couple of years ago. The paper can be found at this link. Thanks are due to Greg Sloan and Kathleen Kraemer for their contributions to the paper. Unfortunately a few years ago a quite different feature was identified in supernovae spectra and also named "the 21 micron feature", apparently the authors of the paper were not aware that the same name was already in use. I have to admit that the "new" 21 micron feature actually peaks very close to 21 microns whereas the one I found long ago in the IRAS LRS data actually peaks at about 20.5 microns--as we found when we got spectra at better wavelength resolution later. It is too late to change the name now, though. I would give much to observe the feature using JWST given the much superior wavelength and spatial resolution it provides, but this type of research is not considered important by time allocation committees these days so the chances of getting time are not good.

End Word:

I see that there is current concern about web content either changing or disappearing without any notice or attempt to preserve the information. While this may in some/many cases be a concern, when thinking about posting content on-line I am always reminded of an old "B.C." comic strip--from June 4th 1980, I believe--which I will describe in words because the strip is no doubt under copywrite and posting a scan of it here (I still have the original) may or may not count as fair use.

Curly sees Peter writing on a stone tablet and asks "What's that?"

Peter replies "I'm writing a history of our society. Millions of years from now I don't want people wondering if we were a bunch of illiterate slobs."

Curly looks at what has been written and observes "Well, this should erase any doubt."

In the same vein, I suggest that posting everything on the internet is not a always good thing...