Astronomy Department
Wesleyan University
Middletown, CT 06459
slawler at wesleyan.edu
M.A. Astronomy, Wesleyan University, expected May 2009
Thesis Topic: The Gas Component of KH 15D's Circumbinary Disk
Thesis Advisor: Professor William Herbst
B.S. Astrophysics, California Institute of Technology, June 2005
Graduate Research Assistant: Wesleyan University, September 2007 - present
My research for my master's thesis, under Professor Herbst, is about KH 15D, a T~Tauri star with a warped, precessing circumbinary disk made up of millimeter-sized grains. I have been observing KH 15D regularly with our on-campus 24" telescope to monitor the evolution of its lightcurve, which is changing as more and more of the binary system is covered by the disk. We know from the lightcurve that the dust in the disk is strongly settled, effectively acting as an opaque shield with a sharp edge as the only currently visible star of the binary system passes behind it. I will be using high-resolution spectra taken over the last few years with the visible star at different elevations above the disk to find out how settled the gas component of the disk is. For this project, I have become very experienced with manipulating spectral data in IDL and IRAF. I presented preliminary results of my work in a poster at the 5th Spitzer Conference this past October showing that there is excess absorption of the NaI D lines visible at the proper radial velocity to be caused by the disk. I am currently working on quantifying this absorption, and will present a more developed poster at the AAS Conference this January.Research Assistant: JPL/Caltech, June 2002 - July 2007
I worked for Dr. Chas Beichman of Caltech's Infrared Processing and Analysis Center for several years. During this time I matured from a completely inexperienced freshman in college to submitting a first author paper on my research (Lawler et al. 2009). When I first started work for Dr. Beichman as a summer student at JPL, I was in charge of finding literature data on $\sim$200 stars in a survey using the MIPS instrument on the Spitzer Space Telescope looking for evidence of debris disks around nearby solar-type stars. For this portion of the job I learned HTML, became an expert with Microsoft Excel, and became proficient on the UNIX operating system.I continued working for Dr. Beichman, who was then at IPAC, for the remainder of my undergraduate career and for two years after I graduated. This work culminated in a paper which was just submitted (Lawler et al. 2009). In this paper, we looked at 152 nearby, solar-type stars to see what percentage of them have excesses detectable by the IRS instrument. We found 16 stars with strong excesses in IRS wavelengths (5-35 microns), which when combined with stars that fit our criteria but had been observed in other surveys gives us 11.8% ± 2.5% of nearby solar-type stars with excesses in these wavelengths. This level of excess indicates the presence of enough dust to produce luminosities greater than ~100 times the luminosity of the dust in our solar system, which, if we assume 10 micron-sized dust grains, corresponds to distances of ~1-35 AU from the host stars. From this project I became an expert at reducing Spitzer IRS data, and gained a great deal of experience with LaTeX and making plots in IDL.
In addition to this research, I also worked on a project with Dr. Mark Swain of JPL looking at the IRS spectrum of the secondary transit of HD 209458b. The main result of this work was in the development of spectroscopic data reduction techniques specific to the IRS instrument, as this was one of the first attempts at using IRS for exoplanetary spectroscopy (Swain et al. 2008).
Spitzer/IRS Spectra of Debris Disks Around Solar-Type Stars. Lawler, S. M., Beichman, C. A., Bryden, G., Ciardi, D., Tanner, A. M., Stapelfeldt, K. R., Lisse, C. M., Harker, D. 2008, ApJ, submittedSurvey of Nearby FGK Stars at 160 um with Spitzer. Tanner, A., Beichman, C., Bryden, G., Lisse, C., Lawler, S. 2008, ApJ, submitted
The Mid-Infrared Spectrum of the Transiting Exoplanet HD 209458b. Swain, M. R., Bouwman, J., Akeson, R. L., Lawler, S., Beichman, C. A. 2008, ApJ, 674, 482
New Debris Disks Around Nearby Main Sequence Stars: Impact on The Direct Detection of Planets. Beichman, C. A., Bryden, G., Stapelfeldt, K. R., Gautier, T. N., Grogan, K., Shao, M., Velusamy, T., Lawler, S. M., Blaylock, M., Rieke, G. H., Lunine, J. I., Fischer, D. A., Marcy, G. W., Greaves, J. S., Wyatt, M. C., Holland, W. S., & Dent, W. R. F. 2006, ApJ, 652, 1674
IRS Spectra of Solar-Type Stars: A Search for Asteroid Belt Analogs. Beichman, C. A., Tanner, A., Bryden, G., Stapelfeldt, K. R., Werner, M. W., Rieke, G. H., Trilling, D. E., Lawler, S., & Gautier, T.N., 2006, ApJ, 639, 1166
Frequency of Debris Disks around Solar-Type Stars: First Results from a Spitzer MIPS Survey. Bryden, G., Beichman, C. A., Trilling, D. E., Rieke, G. H., Holmes, E. K., Lawler, S. M., Stapelfeldt, K. R., Werner, M. W., Gautier, T. N., Blaylock, M., Gordon, K. D., Stansberry, J. A., Su, K. Y. L. 2006, ApJ, 636, 1098
The Gas Component of the KH 15D Transition Disk. Lawler, S. M., Hamilton, C. M., Herbst, W., Johns-Krull, C. M., Mundt, R., Redfield, S., & Winn, J. N. 2009, AAS Meeting Abstracts, 213, 409.08The Gas Component of the KH 15D Transition Disk. Lawler, S. M., Hamilton, C. M., Herbst, W., Johns-Krull, C. M., Mundt, R., & Winn, J. N. 2008, Spitzer Disks Conference
Spitzer Survey of Nearby Debris Disks at 160 Microns. Tanner, A., Beichman, C. A., Bryden, G., & Lawler, S., 2007, BAAS, 38, 814
The Mid-Infrared Spectrum of HD 209458b. Swain, M. R., Bouwman, J., Akeson, R. L., Lawler, S., Beichman, C. A. 2007, BAAS, 38, 229
Spitzer/IRS Observations of HD 209458. Swain, M. R., Bouwman, J., Akeson, R. L., Lawler, S., Beichman, C. A. 2007, BAAS, 38, 274
A Search for Warm Dust in the Habitable Zones around Solar-Type Stars. Lawler, S. M., Ciardi, D., Beichman, C. A., Tanner, A., Bryden, G., Stapelfeldt, K., Harker, D., & Akeson, R. 2006, TPF/Darwin Workshop, Pasadena, CA, Nov. 8-11
A Search for Warm Dust in the Habitable Zones around Solar-Type Stars. Lawler, S. M., Ciardi, D., Beichman, C. A., Tanner, A., Bryden, G., Stapelfeldt, K., Harker, D., & Akeson, R. 2006, Cool Stars 14 Conference, Pasadena, CA, Nov. 6-10
An Overview of Cometary and Asteroidal Debris Disks Around Main Sequence Stars. Beichman, C. A., Bryden, G., Gautier, N., Lawler, S., Werner, M., Trilling, D., Stansberry, J., Su, K., Siegler, N., & Rieke, G. 2006, BAAS, 38, 486
Teaching Assistant: Wesleyan Astronomy Department (September 2007 - Present)
Astr 155 - Introductory Astronomy, for physics and astronomy majors
Astr 105 - Descriptive Astronomy, for non-science majors
Astr 103 - The Planets, for non-science majors
Duties involve grading, running homework help sessions, holding office hours, running lab sessions, and running observing sessions with our rooftop 16" telesope.Public Observing: Wesleyan Astronomy Department (September 2007 - Present)
I lead public observing sessions with our rooftop 16" telescopeProject ASTRO (July 2008 - Present)
I provide support for a partner teacher at an elementary school in inner city Hartford, CT by helping with astronomy lessons and a StarLab planetarium presentationTeacher: Mad Science Inc., Van Nuys, CA (February - November 2006)
I led hands-on science classes and demonstrations for groups of elementary schools children throughout the greater Los Angeles areaTeaching Assistant: Astrophysics Department, California Institute of Technology (March - June 2005)
Astrophysics 1 - The Evolving Universe (for non-astronomy majors)
Duties involved grading, holding office hours for homework help, and giving a one hour lecture every other week
24" Observing Program Coordinator: Astronomy Department, Wesleyan University
I train the 10-15 students who volunteer each semester for the observing program on Van Vleck Observatory's research-grade 24" telescope, and I am on call to answer questions and fix any problems that come up with the telescope during observing nights, which is nearly every clear night while classes are in session. I have also helped design the data reduction pipeline for the new CCD which was installed last year.WIYN 0.9m Telescope, Kitt Peak National Observatory, AZ
I accompanied Prof. Dana Casetti (Wesleyan/Yale) on her observing run this past October using the MOSAIC instrument. I helped with target selection and troubleshooting during the run. I was also able to use this opportunity to take several observations of KH 15D which happened to be close to peak brightness during this run.Palomar 200" Telescope, Palomar Observatory, CA
I accompanied Dr. Angelle Tanner on three observing runs between fall of 2005 and spring of 2007. Dr. Tanner was using the PALAO/PHARO adaptive optics system, along with a coronagraph to look for brown dwarf and smaller companions to nearby F, G, K, and M stars.
IDL: manipulating photometric and spectral data, and for making figures
IRAF: photometric and spectroscopic data reduction
UNIX
LaTeX
HTML: webmaster for the Historical Society of the Crescenta Valley
MaxIm DL: common software for CCD control
Spice: for reducing Spitzer IRS data
Microsoft Excel: useful for organizing data in large surveys
Much less colorful, but sometimes necessary: Here