Email: fortsonphysics.umn.edu
WWW: Web Site

<b>High Energy Astrophysics</b>
My research interests are in experimental high-energy astrophysics. As a member of the <a target='_blank' href='http://veritas.sao.arizona.edu/'>VERITAS</a> (Very Energetic Radiation Imaging Telescope Array System), I study gamma rays detected from active galactic nuclei. Gamma-ray astronomy probes the extreme physics of systems such as the black holes at the centers of active galaxies. These systems emit radiation throughout the electromagnetic spectrum and I work to combine the information obtained from telescopes operating at multiple wavelengths to decipher how the active galaxy powers the emission of gamma rays. I am also working on the next generation ground-based gamma ray array, <a target='_blank' href='http://www.agis-observatory.org'>AGIS</a> (Advanced Gamma-ray Imaging System) comprising ~50 telescopes in an array with the aim of greatly improving the angular resolution and sensitivity to high energy gamma ray emission.

<b>Galaxy Zoo and Zooniverse Citizen Science Projects</b>
I am also a member of the <a target='_blank' href='http://zooniverse.org'>Zooniverse collaboration</a> which is a collection of online research projects that require human pattern matching abilities to sort through the millions of images and other data products being generated by telescopes, ocean sensors, satellites and digitized texts. I work particularly with Galaxy Zoo data where over 250,000 members of the general public have provided a highly accurate classification of a million galaxies from the Sloan Digital Sky Survey. I am currently studying a sample of barred galaxies derived from Galaxy Zoo to study the relationship between active galactic nuclei and galactic bars.

Ongoing Scientific Projects:

• Very Energetic Radiation Imaging Telescope Array System (VERITAS)

2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002


Latest Journal Publications

1. "Periastron Observations of TeV Gamma-Ray Emission from a Binary System with a 50-year Period", The Astrophysical Journal Letters, Volume 867, Issue 1, article id. L19, 8 pp. (2018) (Nov 2018)
2. "VERITAS and Fermi-LAT Observations of TeV Gamma-Ray Sources Discovered by HAWC in the 2HWC Catalog", The Astrophysical Journal, Volume 866, Issue 1, article id. 24, 18 pp. (2018) (Oct 2018)
3. "Measurement of cosmic-ray electrons at TeV energies by VERITAS", Physical Review D, Volume 98, Issue 6, id.062004 (Sep 2018)
4. "Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A", Science, Volume 361, Issue 6398, id. eaat1378 (2018) (Jul 2018)
5. "Measurement of the iron spectrum in cosmic rays by VERITAS", Physical Review D, Volume 98, Issue 2, id.022009 (Jul 2018)
6. "HESS J1943+213: An Extreme Blazar Shining through the Galactic Plane", The Astrophysical Journal, Volume 862, Issue 1, article id. 41, 15 pp. (2018) (Jul 2018)
7. "VERITAS Observations of the BL Lac Object TXS 0506+056", The Astrophysical Journal Letters, Volume 861, Issue 2, article id. L20, 6 pp. (2018) (Jul 2018)
8. "A Very High Energy γ-Ray Survey toward the Cygnus Region of the Galaxy", The Astrophysical Journal, Volume 861, Issue 2, article id. 134, 33 pp. (2018) (Jul 2018)
9. "VizieR Online Data Catalog: Five years of blazar observations with VERITAS (Archambault+, 2016)", VizieR On-line Data Catalog: J/AJ/151/142. Originally published in: 2016AJ....151..142A (Apr 2018)
10. "A Strong Limit on the Very-high-energy Emission from GRB 150323A", The Astrophysical Journal, Volume 857, Issue 1, article id. 33, 6 pp. (2018) (Apr 2018)
11. "Multiwavelength Observations of the Blazar BL Lacertae: A New Fast TeV Gamma-Ray Flare", The Astrophysical Journal, Volume 856, Issue 2, article id. 95, 14 pp. (2018) (Apr 2018)
12. "Multiwavelength follow-up of a rare IceCube neutrino multiplet", Astronomy &#38; Astrophysics, Volume 607, id.A115, 22 pp (Nov 2017)
13. "Discovery of Very-high-energy Emission from RGB J2243+203 and Derivation of Its Redshift Upper Limit", The Astrophysical Journal Supplement Series, Volume 233, Issue 1, article id. 7, 6 pp. (2017) (Nov 2017)
14. "Very-High-Energy γ-Ray Observations of the Blazar 1ES 2344+514 with VERITAS", Monthly Notices of the Royal Astronomical Society, Volume 471, Issue 2, p.2117-2123 (Oct 2017)
15. "VERITAS contributions to the 35th International Cosmic Ray Conference", arXiv:1709.07843 (Sep 2017)
16. "Cherenkov Telescope Array Contributions to the 35th International Cosmic Ray Conference (ICRC2017)", arXiv:1709.03483 (Sep 2017)
17. "Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009", Astronomy &#38; Astrophysics, Volume 603, id.A31, 30 pp (Jul 2017)
18. "Gamma-ray observations under bright moonlight with VERITAS", Astroparticle Physics, Volume 91, p. 34-43 (May 2017)
19. "Dark matter constraints from a joint analysis of dwarf Spheroidal galaxy observations with VERITAS", Physical Review D, Volume 95, Issue 8, id.082001 (Apr 2017)
20. "Gamma-Ray Observations of Tycho’s Supernova Remnant with VERITAS and Fermi", The Astrophysical Journal, Volume 836, Issue 1, article id. 23, 8 pp. (2017) (Feb 2017)

Latest Conference Proceedings

1. "The Science and Design of the AGIS Observatory", American Astronomical Society, AAS Meeting #215, #441.07; Bulletin of the American Astronomical Society, Vol. 42, p.401 (Jan 2010)
2. "Status of the VERITAS Observatory", HIGH ENERGY GAMMA-RAY ASTRONOMY: Proceedings of the 4th International Meeting on High Energy Gamma-Ray Astronomy. AIP Conference Proceedings, Volume 1085, pp. 657-660 (2008) (Dec 2008)
3. "Status report from VERITAS", Journal of Physics: Conference Series, Volume 60, Issue 1, pp. 34-39 (2007) (Mar 2007)
4. "Deployment of the VERITAS observatory", Journal of Physics: Conference Series, Volume 47, Issue 1, pp. 232-237 (2006) (Oct 2006)
5. "VERITAS: status c.2005", PARTICLES AND NUCLEI: Seventeenth Internatinal Conference on Particles and Nuclei. AIP Conference Proceedings, Volume 842, pp. 1001-1003 (2006) (Jul 2006)
6. "The VERITAS Prototype and the Upcoming VERITAS Array", HIGH ENERGY GAMMA-RAY ASTRONOMY: 2nd International Symposium on High Energy Gamma-Ray Astronomy. AIP Conference Proceedings, Volume 745, pp. 633-638 (2005) (Feb 2005)
7. "Very High Energy Observations of Gamma Ray Bursts with the Whipple/VERITAS Telescopes", High Energy Gamma-Ray Astronomy: 2nd International Symposium, Proceedings of the conference held 26-30 July 2004 in Heidelberg (Germany). Edited by Felix A. Aharonian, Heinz J. Völk, and Dieter Horns. AIP Conference Proceedings, Volume 745. New York: A
8. "The very high energy gamma ray spectra of IES 1959+650 and Mrk 421 as measured with the Whipple 10 m telescope", HIGH ENERGY GAMMA-RAY ASTRONOMY: 2nd International Symposium on High Energy Gamma-Ray Astronomy. AIP Conference Proceedings, Volume 745, pp. 462-467 (2005) (Feb 2005)
9. "Recent Observations of IC443 with the Whipple 10m Telescope", HIGH ENERGY GAMMA-RAY ASTRONOMY: 2nd International Symposium on High Energy Gamma-Ray Astronomy. AIP Conference Proceedings, Volume 745, pp. 275-280 (2005) (Feb 2005)
10. "Science capabilities of the VERITAS array of 10m imaging atmospheric Cerenkov gamma-ray detectors", Discoveries and Research Prospects from 6- to 10-Meter-Class Telescopes II. Edited by Guhathakurta, Puragra. Proceedings of the SPIE, Volume 4834, pp. 276-287 (2003) (Feb 2003)