Steven L Snowden

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Steven L Snowden

  • Astrophysicist (Emeritus)
  • NASA/GSFC
  • Mail Code: 662
  • Employer: EMERITUS
  • Brief Bio

    After receiving his Ph.D, Steve Snowden worked for half a year on the Diffuse X-ray Spectrometer, a shuttle attached payload of the University of Wisconsin Space Physics Laboratory. After that he spent five and a half years at the Max Planck Institute for Extraterrestrial Physics in Germany, working on the ROSAT project, primarily on the soft X-ray diffuse background from the all-sky survey. Steve joined the USRSDC at GSFC in 1993 August, where he worked until 1998 when he took the position of lead scientist for the XMM GOF. In 2005 Steve became the Deputy Project Scientist and Technical Officer for the NASA part of the XMM-Newton project.  In 2009 Steve became the Project Scientist.

    Steve's primary responsibility at GSFC is science support for the XMM Guest Observer Facility. This includes support for the US XMM users community from the proposal process to the analysis of XMM data.

    Current Projects

    XMM-Newton Guest Observer Facility

    HaloSat

    HaloSat is a CubeSat with Principle Investigator Phil Kaaret. It will study the hot plasma emission from the Galaxy primarily focusing on the Galactic halo but will also study solar wind charge exchange emission from the solar system.

    CuPID

    CuPID is a CubeSat project with Principle Investigator Brian Walsh. CuPID will study solar wind charge exchange emission from the cusps of Earth's magnetosphere.

    Positions/Employment

    10/2009 - Present

    NASA XMM-Newton Project Scientist

    NASA, GSFC
    11/2005 - 10/2009

    NASA XMM-Newton Deputy Project Scientist and COTR

    NASA, GSFC
    1997 - 11/2005

    NASA/GSFC GOF Lead Scientist

    USRA, GSFC
    8/1993 - 1997

    NASA/GSFC ROSAT GOF Scientist

    USRA, GSFC

    Education

    Steve received his BS in Mathematics, Physics, and Astronomy in 1978 from the University of Washington, his MS in physics in 1979 and PhD in physics in 1986 from the University of Wisconsin - Madison. The title of Steve's thesis is: Neutral Hydrogen and the Spatial Structure of the Diffuse X-ray Background.

    Professional Societies

    American Astronomical Society, 1983 - Present
    AAS High Energy Astrophysics Division, 1983 - Present

    Awards

    2015 John C. Lindsay Memorial Award

    NASA Exceptional Scientific Achievement Medal

    NASA Robert H. Goddard (RHG) Exceptional Achievement for Science

    "For developing the first physically coherent picture of the Local Hot Bubble"

    2002 Universities Space Research Association (USRA) Programmatic Excellence Award

    1999 Max Planck Institute for Extraterrestrial Physics (MPE) Certificate of Appreciation for work on the ROSAT mission

    1995 GSFC Laboratory for High Energy Astrophysics (LHEA) Peer Award

    Selected Publications

    Refereed

    Snowden, S. L., C. Heiles, D. Koutroumpa, et al. K. D. Kuntz, R. Lallement, D. McCammon, and J. E. Peek. 2015. "Revisiting the Local Leo Cold Cloud and Revised Constraints on the Local Hot Bubble." ApJ, 806 (1): 119 [10.1088/0004-637X/806/1/119]

    Snowden, S. L., D. Koutroumpa, K. D. Kuntz, R. Lallement, and L. Puspitarini. 2015. "The North Galactic Pole Rift and the Local Hot Bubble." ApJ, 806 (1): 120 [10.1088/0004-637X/806/1/120]

    Snowden, S., M. Chiao, M. Collier, et al. F. Porter, N. Thomas, T. Cravens, I. Robertson, M. Galeazzi, Y. Uprety, E. Ursino, D. Koutroumpa, K. Kuntz, R. Lallement, L. Puspitarini, S. Lepri, D. McCammon, K. Morgan, and B. Walsh. 2014. "Pressure Equilibrium between the Local Interstellar Clouds and the Local Hot Bubble." Astrophysical Journal Letters, 791: L14 [10.1088/2041-8205/791/1/L14]

    Galeazzi, M., M. Chiao, M. Collier, et al. T. Cravens, D. Koutroumpa, K. Kuntz, R. Lallement, S. Lepri, D. McCammon, K. Morgan, F. Porter, I. Robertson, S. Snowden, N. Thomas, Y. Uprety, E. Ursino, and B. Walsh. 2014. "The origin of the local 1/4-keV X-ray flux in both charge exchange and a hot bubble." Nature, 512: 171-173 [10.1038/nature13525]

    Kuntz, K. D., and S. L. Snowden. 2010. "The Chandra M101 Megasecond: Diffuse Emission." The Astrophysical Journal Supplement, 188: 46 [Full Text (Link)] [10.1088/0067-0049/188/1/46]

    Snowden, S. L. 2009. "What Can Be Learned from X-ray Spectroscopy Concerning Hot Gas in the Local Bubble and Charge Exchange Processes?" Space Science Reviews, 143: 253 [Full Text (Link)] [10.1007/s11214-008-9343-2]

    Snowden, S. L., M. R. Collier, T. Cravens, et al. K. D. Kuntz, S. T. Lepri, I. Robertson, and L. Tomas. 2009. "Observation of Solar Wind Charge Exchange Emission from Exospheric Material in and Outside Earth's Magnetosheath 2008 September 25." The Astrophysical Journal, 691: 372 [Full Text (Link)] [10.1088/0004-637X/691/1/372]

    Koutroumpa, D., M. R. Collier, K. D. Kuntz, R. Lallement, and S. L. Snowden. 2009. "Solar Wind Charge Exchange Emission from the Helium Focusing Cone: Model to Data Comparison." The Astrophysical Journal, 697: 1214 [Full Text (Link)] [10.1088/0004-637X/697/2/1214]

    Kuntz, K. D., and S. L. Snowden. 2008. "The X-Ray-Emitting Components toward l = 111°: The Local Hot Bubble and Beyond." The Astrophysical Journal, 674: 209 [Full Text (Link)] [10.1086/524719]

    Snowden, S. L., R. F. Mushotzky, K. D. Kuntz, and D. S. Davis. 2008. "A catalog of galaxy clusters observed by XMM-Newton." Astronomy and Astrophysics, 478: 615 [Full Text (Link)] [10.1051/0004-6361:20077930]

    Kuntz, K. D., and S. L. Snowden. 2008. "The EPIC-MOS particle-induced background spectra." Astronomy and Astrophysics, 478: 575 [Full Text (Link)] [10.1051/0004-6361:20077912]

    Snowden, S. L., M. R. Collier, and K. D. Kuntz. 2004. "XMM-Newton Observation of Solar Wind Charge Exchange Emission." The Astrophysical Journal, 610: 1182 [Full Text (Link)] [10.1086/421841]

    Snowden, S. L., M. J. Freyberg, K. D. Kuntz, and W. T. Sanders. 2000. "A Catalog of Soft X-Ray Shadows, and More Contemplation of the 1/4 KEV Background." The Astrophysical Journal Supplement Series, 128: 171 [Full Text (Link)] [10.1086/313378]

    Brief Bio

    After receiving his Ph.D, Steve Snowden worked for half a year on the Diffuse X-ray Spectrometer, a shuttle attached payload of the University of Wisconsin Space Physics Laboratory. After that he spent five and a half years at the Max Planck Institute for Extraterrestrial Physics in Germany, working on the ROSAT project, primarily on the soft X-ray diffuse background from the all-sky survey. Steve joined the USRSDC at GSFC in 1993 August, where he worked until 1998 when he took the position of lead scientist for the XMM GOF. In 2005 Steve became the Deputy Project Scientist and Technical Officer for the NASA part of the XMM-Newton project.  In 2009 Steve became the Project Scientist.

    Steve's primary responsibility at GSFC is science support for the XMM Guest Observer Facility. This includes support for the US XMM users community from the proposal process to the analysis of XMM data.

    Selected Publications

    Refereed

    Snowden, S. L., C. Heiles, D. Koutroumpa, et al. K. D. Kuntz, R. Lallement, D. McCammon, and J. E. Peek. 2015. "Revisiting the Local Leo Cold Cloud and Revised Constraints on the Local Hot Bubble." ApJ 806 (1): 119 [10.1088/0004-637X/806/1/119]

    Snowden, S. L., D. Koutroumpa, K. D. Kuntz, R. Lallement, and L. Puspitarini. 2015. "The North Galactic Pole Rift and the Local Hot Bubble." ApJ 806 (1): 120 [10.1088/0004-637X/806/1/120]

    Snowden, S., M. Chiao, M. Collier, et al. F. Porter, N. Thomas, T. Cravens, I. Robertson, M. Galeazzi, Y. Uprety, E. Ursino, D. Koutroumpa, K. Kuntz, R. Lallement, L. Puspitarini, S. Lepri, D. McCammon, K. Morgan, and B. Walsh. 2014. "Pressure Equilibrium between the Local Interstellar Clouds and the Local Hot Bubble." Astrophysical Journal Letters 791 L14 [10.1088/2041-8205/791/1/L14]

    Galeazzi, M., M. Chiao, M. Collier, et al. T. Cravens, D. Koutroumpa, K. Kuntz, R. Lallement, S. Lepri, D. McCammon, K. Morgan, F. Porter, I. Robertson, S. Snowden, N. Thomas, Y. Uprety, E. Ursino, and B. Walsh. 2014. "The origin of the local 1/4-keV X-ray flux in both charge exchange and a hot bubble." Nature 512 171-173 [10.1038/nature13525]

    Kuntz, K. D., and S. L. Snowden. 2010. "The Chandra M101 Megasecond: Diffuse Emission." The Astrophysical Journal Supplement 188 46 [Full Text (Link)] [10.1088/0067-0049/188/1/46]

    Snowden, S. L. 2009. "What Can Be Learned from X-ray Spectroscopy Concerning Hot Gas in the Local Bubble and Charge Exchange Processes?" Space Science Reviews 143 253 [Full Text (Link)] [10.1007/s11214-008-9343-2]

    Snowden, S. L., M. R. Collier, T. Cravens, et al. K. D. Kuntz, S. T. Lepri, I. Robertson, and L. Tomas. 2009. "Observation of Solar Wind Charge Exchange Emission from Exospheric Material in and Outside Earth's Magnetosheath 2008 September 25." The Astrophysical Journal 691 372 [Full Text (Link)] [10.1088/0004-637X/691/1/372]

    Koutroumpa, D., M. R. Collier, K. D. Kuntz, R. Lallement, and S. L. Snowden. 2009. "Solar Wind Charge Exchange Emission from the Helium Focusing Cone: Model to Data Comparison." The Astrophysical Journal 697 1214 [Full Text (Link)] [10.1088/0004-637X/697/2/1214]

    Kuntz, K. D., and S. L. Snowden. 2008. "The X-Ray-Emitting Components toward l = 111°: The Local Hot Bubble and Beyond." The Astrophysical Journal 674 209 [Full Text (Link)] [10.1086/524719]

    Snowden, S. L., R. F. Mushotzky, K. D. Kuntz, and D. S. Davis. 2008. "A catalog of galaxy clusters observed by XMM-Newton." Astronomy and Astrophysics 478 615 [Full Text (Link)] [10.1051/0004-6361:20077930]

    Kuntz, K. D., and S. L. Snowden. 2008. "The EPIC-MOS particle-induced background spectra." Astronomy and Astrophysics 478 575 [Full Text (Link)] [10.1051/0004-6361:20077912]

    Snowden, S. L., M. R. Collier, and K. D. Kuntz. 2004. "XMM-Newton Observation of Solar Wind Charge Exchange Emission." The Astrophysical Journal 610 1182 [Full Text (Link)] [10.1086/421841]

    Snowden, S. L., M. J. Freyberg, K. D. Kuntz, and W. T. Sanders. 2000. "A Catalog of Soft X-Ray Shadows, and More Contemplation of the 1/4 KEV Background." The Astrophysical Journal Supplement Series 128 171 [Full Text (Link)] [10.1086/313378]

                                                                                                                                                                                            
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