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Gordon Dean Holman
Photograph of Gordon Dean Holman
Born1949
NationalityAmerican
EducationEmeritus, PhD
OccupationAstrophysicist

Gordon Dean Holman is an emeritus research astrophysicist at the National Aeronautics and Space Administration's (NASA’s) Goddard Space Flight Center in Greenbelt, Maryland.[1]  His research mostly focused on obtaining an understanding of high-energy radiation from astronomical objects.  This radiation cannot be observed from Earth's surface, but is observed with instruments on satellites launched to orbits above Earth's atmosphere.[2]  It is primarily emitted by high-energy electrons interacting with ions.[3] These electrons also emit radiation at radio frequencies which is observed from Earth's surface.  Consequently, these observations from space and radio telescopes provide a view of hot gas and energetic particles[4] in the Universe that could not otherwise be obtained.  Holman has specialized in the interpretation of these observed emissions to determine the origin and evolution of this hot gas and energetic particles.  He has been described as "not just a theorist, he also looks at the data".[5]

Holman spent most of his career as a solar physicist on the Science Team of the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI),[6] a space observatory designed to observe X-ray emission from solar flares.[7]  He has authored or co-authored over one-hundred research papers for scientific journals as well as over one-hundred published abstracts of presentations at scientific meetings.[8][9] They provide new information about solar flares and active regions as well as clusters of galaxies and disconnection events in comet tails (see Research section below).  He has also authored review articles, science magazine articles, book reviews, proposals, technical reports, referee reports, proposal reviews, and Web sites.  He is author of the April 2006 Scientific American article "The Mysterious Origins of Solar Flares"[10] and principal author of the Solar Flare Theory Educational Web Pages[11] (last revised in 2007).  The magazine Physics Today published his article "Solar Eruptive Events" in April 2012.[12]  He is author of the book "The Scientific Method: Why science is a crucial process for human progress, not just another academic subject or belief"[13]

Education

[edit]

After graduating from Northeast High School in Fort Lauderdale, Florida, in 1967, Holman obtained a Bachelor of Science degree in physics with a minor in mathematics at Florida State University in 1971.[1] 

In the summer of 1970 Holman was awarded an International Association for the Exchange of Students for Technical Experience (IAESTE) traineeship at the Physikalisch-Techniche Bundesanstalt in Braunschweig, Germany, where he interned with a group studying the stimulated emission of trapped electrons from solid surfaces.[1]  This led to a research note in the journal Physica Status Solidi.[14]

Holman obtained a Master of Science degree in physics in 1973 and Doctor of Philosophy degree in astrophysics in 1977, both from the University of North Carolina at Chapel Hill.[1]  His PhD dissertation, obtained under the supervision of Dr. Wayne A. Christiansen, was titled "Models for X-Ray and Radio Emission from Clusters of Galaxies".[15]  

Career

[edit]

Holman started his career as a physics graduate student teaching observational laboratories for freshman astronomy students at the Morehead Planetarium and Science Center in Chapel Hill, NC.[1]  He also assisted with lecture courses in astronomy, physics, and Physics and Society.[1]  

In 1977 Holman was hired as a lecturer in the Astronomy Program at the University of Maryland, College Park.[1]  In August 1977 he was awarded a two-year Postdoctoral Fellowship at the Maryland Center for Fundamental Physics.  He was hired as a Research associate in 1979 by Mukul Kundu to work with his solar radio astronomy group.  He remained with this group at the University of Maryland for four years.[1]  With Kundu he coedited the Proceedings of the International Astronomical Union (IAU) Symposium No, 107, "Unstable Current Systems and Plasma Instabilities in Astrophysics".[16]

In 1983 Holman was awarded a two-year National Academy of Sciences / National Research Council Senior Research Associateship at NASA's Goddard Space Flight Center.[17]  He was hired into a federal civil service position at Goddard in 1985[1] in what is now the Laboratory for Solar Physics, where he remained until he retired in 2018.  In 1988 Holman spent roughly six months at NASA Headquarters in Washington DC assisting with NASA's Space physics proposal review process.[1]  

While at NASA Goddard, Holman supervised four PhD students[18][19][20][21] (through UNC Chapel Hill and The Catholic University of America) and mentored numerous Postdoctoral Fellows and summer interns.  He contributed to the NASA / UC Berkeley Lesson Series Exploring Magnetism.[22]

Holman is a member of the American Astronomical Society (AAS),[23] American Geophysical Union (AGU),[1] International Astronomical Union (IAU),[24] and the Committee on Space Research (COSPAR).  He was an elected member of the SPD Committee of the Solar Physics Division (SPD) of the AAS in 2005 – 2007.[25]

Research

[edit]

Hot gas and energetic electrons in giant clusters of galaxies

[edit]

In the early 1970s extended sources of X-ray emission were detected in large clusters of galaxies with the Uhuru satellite.[26]  Extended radio sources were also observed in some large clusters such as Coma and Perseus.  In his PhD Thesis[27] Holman explored the implications of models that explained both sources as arising from the same population of energetic electrons.  Subsequent observations in the mid-1970s indicated that the X-ray emission is thermal radiation from hot, ionized thermal gas (plasma) with a temperature near 100 million degrees, not more energetic non-thermal electrons.[28]  Holman and collaborators showed how the population of non-thermal electrons responsible for the radio emission could also heat the plasma producing the X-rays, providing a connection between the two sources.[29][30] 

It had been argued that energetic charged particles streaming through magnetized thermal plasma could only propagate at the Alfvén speed because of interaction with Alfvén waves in the plasma.[31]  This would restrict the size of the radio source.[32]  Holman and collaborators showed that the damping of short-wavelength Alfvén waves could keep the particles from being slowed to this speed, especially in the exceptionally hot plasma in the clusters of galaxies.[33]  

Maser emission from the Sun and active stars

[edit]

In 1978 and later rapid spikes of microwave radiation were observed during the impulsive phase of some solar flares.  The high brightness of these spikes indicated that a coherent radiation process must be responsible.[34]  Holman and colleagues showed that maser emission from a distribution of high-energy electrons partially mirrored at the bottom of a magnetic loop could be responsible for these spikes.[35]  This mechanism is also likely to be responsible for bright radio flares from active stars such as the M-dwarf star AD Leo.[36] 

Radio emission from shock waves driven by solar eruptions

[edit]

Eruptions of rapidly moving material from the Sun, coronal mass ejections, drive shock waves in the solar corona and beyond.[37]  Radio emission has long been observed from these shock waves. This solar radio emission was given the designation "Type II radio burst" in the early 1950s.  Holman and Pesses[38] hypothesized that Type II emission is stimulated by electrons energized by shock drift acceleration.  They found the hypothesis to be sound and identified implications for the geometry of the shock wave and the corresponding sources of radio emission.  Holman has collaborated on observational studies examining the initiation of coronal mass ejections[39] and the properties of Type II emission.[40]

Coronal magnetic field in active regions on the Sun

[edit]

The Sun's magnetic field is enhanced in active regions, where sunspots are located.  Major solar flares and eruptions also originate in active regions.[41]  (However, in 2015 Holman and collaborator Adi Foord[42] found that a significant X-ray flare occurred outside any active region,[43] in association with the eruption of a long, quiescent filament.) The enhanced magnetic field and its evolution is understood to be the source of energy for this activity.[44]  Therefore, it is important to know the strength and structure of active region magnetic fields.  

The wavelength of microwave emission from active regions provides a measure of the magnetic field strength in hot, magnetically confined structures at coronal temperatures.[45]  In the late 1980s and early 1990s, Holman and collaborators carried out the Coronal Magnetic Structures Observing Campaign (CoMStOC).[46][47]  This campaign obtained observations of multiple active regions with the Very Large Array (VLA) radio telescope in New Mexico combined with X-ray observations from the Flat Crystal Spectrometer on the Solar Maximum Mission (SMM) satellite as well as other relevant observations.  Magnetic field strengths up to 600 Gauss were deduced, while the presence of cooler plasma and higher Alfvén speeds than expected in the corona were also inferred.[48][49] 

Comet ion tail disconnection events

[edit]

A particularly impressive feature observed in comets is the disconnection event, when the ion tail (also called gas or plasma tail) of the comet disconnects and moves away from the head.[50]  There are several possible explanations for this phenomenon, one of which is magnetic reconnection at the front of the comet where the tail magnetic field wraps around the nucleus.[51]  

In 1985 Holman contributed to the NASA Jet Propulsion Laboratory publication "The comet Giacobini-Zinner handbook. An observer's guide to the first comet to be explored by a spacecraft".[52][53] The intercepting spacecraft was the International Cometary Explorer (ICE). When Halley's comet made its appearance in 1986, ICE was nearby obtaining measurements of the thermal and magnetic properties of the solar wind through which the comet was traveling.  Brosius, Holman and collaborators[54] examined two disconnection events that occurred during this period of time along with the properties of the solar wind measured by ICE.  They concluded that the first disconnection event was most likely front-side magnetic reconnection caused by a polarity reversal in the solar wind magnetic field impacting the comet.  The second event might have also been caused by a polarity reversal, but a high density and velocity compression region was present as well that might have caused or contributed to the event.  

Energetic particles and magnetic reconnection in solar flares

[edit]

Holman was Co-Investigator and member of the science team for the Ramaty High Energy Solar Spectroscopic Imager (RHESSI).[6]  The RHESSI satellite was an observatory designed to explore the basic physics of particle acceleration and explosive energy release in solar flares by obtaining high-resolution spectroscopic imaging of flares in X rays and gamma rays.[55]  It was launched in early 2002 and was decommissioned in 2018.[56]  Much of Holman's research focuses on analysis of the RHESSI X-ray data[4] to deduce the origin and evolution of energetic electrons produced in solar flares.[57][58]

Holman has collaborated on major studies of the partition of energy in solar eruptive events[59][60][61] (large eruptions consisting of both a flare and a coronal mass ejection[62]). Observational studies by him and his collaborators have helped establish that the primary site of energy release is magnetic reconnection in the corona,[63][64][65][66] seen as a cusp at the top of flare magnetic loops.[67] He has examined the impact of a return current that is expected to be co-spatial with the streaming energetic electrons responsible for the highest energy X-ray emission from flares[68] and, with Meriem Alaoui Abdallaoui,[69][70] continues to examine the impact of the return current on flare evolution.[71][72]

Multiple reviews of this and related research have been authored or coauthored by Holman.[73][74][75][76] In 2016 he authored a review addressing future observations from space that would lead to substantial progress toward our understanding of solar activity.[77]

Awards and honors

[edit]

References

[edit]
  1. ^ a b c d e f g h i j k "Gordon D. Holman NASA Biography (2015)".
  2. ^ "What are Hard X-Rays?". Solar Flare Theory Educational Web Pages. Retrieved 2023-04-17.
  3. ^ "Fast Electrons, Bremsstrahlung, & Bowling". Solar Flare Theory Educational Web Pages. Retrieved 2023-04-17.
  4. ^ a b "Why Study Solar Flares in Hard X-Rays?". Solar Flare Theory Educational Web Site.
  5. ^ Holman, Gordon D. (April 25, 2014). "The Puzzle of Energy Release in Solar Eruptive Events". NASA Goddard Space Flight Center Scientific Colloquia, quote from introduction by Brian R. Dennis (Video).
  6. ^ a b "The Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI)" (PDF).
  7. ^ "What is a Solar Flare?". Solar Flare Theory Educational Web Pages. Retrieved 2023-04-17.
  8. ^ Holman, Gordon. "ResearchGate".
  9. ^ Holman, Gordon. "SAO/NASA Astrophysics Data System (ADS): Gordon Holman". Harvard Smithsonian Astrophysical Observatory / NASA Astrophysics Data System.
  10. ^ Holman, Gordon D. (April 1, 2006). "The Mysterious Origins of Solar Flares – Scientific American". Scientific American.
  11. ^ Holman, Gordon. "Solar Flare Theory Educational Web Pages".
  12. ^ Holman, Gordon D. (April 1, 2012). "Solar Eruptive Events: Physics Today: Vol 65, No 4". doi:10.1063/PT.3.1520. {{cite journal}}: Cite journal requires |journal= (help)
  13. ^ Holman, Gordon (2023). The Scientific Method: Why science is a crucial process for human progress, not just another academic subject or belief. Kindle Direct Publishing. ISBN 979-8854425674.
  14. ^ Kaul, W.; Sutter, E.; Holman, G. D. (1971). "Optically stimulated electron emission from LiF with thermal bleaching". Physica Status Solidi A. 4 (2): K101–K104. Bibcode:1971PSSAR...4..101K. doi:10.1002/pssa.2210040235.
  15. ^ Holman, Gordon D. (1977). "Models for X-ray and Radio Emission from Clusters of Galaxies – NASA/ADS". Bibcode:1977PhDT.........4H.
  16. ^ "Symposium – International Astronomical Union: Volume 107 – | Cambridge Core cambridge.org".
  17. ^
    Certification of NAS/NRC Research Associate position at NASA GSFC
    Certificate certifying completion by Gordon D. Holman of NAS NRC Research Associate position at NASA's Goddard Space Flight Center.
  18. ^ Benka, Stephen G. (1991-01-01). A Thermal/nonthermal Approach to Solar Flares (Thesis). Bibcode:1991PhDT........12B.
  19. ^ Sui, Linhui (2005). Modeling Solar Flare Hard X-ray Images and Spectra Observed with RHESSI. Greenbelt, MD: NASA/TM – 2005-212776. Bibcode:2004PhDT........32S.
  20. ^ Su, Yang; Holman, Gordon D.; Dennis, Brian R. (2011-04-01). "Evidence for the Full Hard X-ray Spectral Signature of Nonuniform Ionization in a Solar Flare". The Astrophysical Journal. 731 (2): 106. Bibcode:2011ApJ...731..106S. doi:10.1088/0004-637X/731/2/106. ISSN 0004-637X. S2CID 120731036.
  21. ^ Alaoui Abdallaoui, Meriem (2018). "Return currents in solar flares: Theory and observations".
  22. ^ "Exploring Magnetism lesson series". cse.ssl.berkeley.edu. Retrieved 2023-04-14.
  23. ^ Holman, Gordon. "Member Directory | American Astronomical Society".
  24. ^ "Gordon D. Holman | IAU".
  25. ^ "Officers and Committees of the Solar Physics Division of the AAS (2000–2010)" (PDF).
  26. ^ "Uhuru | Center for Astrophysics". www.cfa.harvard.edu. Retrieved 2023-03-07.
  27. ^ Holman, Gordon D. (1977). Models for X-ray and Radio Emission from Clusters of Galaxies. University of North Carolina at Chapel Hill PhD Dissertation. Bibcode:1977PhDT.........4H.
  28. ^ Mitchell, R. J.; Ives, J. C.; Culhane, J. L. (1977). "The X-ray temperatures of eight clusters of galaxies and their relationship to other cluster properties". Retrieved 2023-04-14.
  29. ^ Lea, S. M.; Holman, G. D. (1978). "X-ray and Radio Emission from Clusters of Galaxies: The Heating of Intracluster Gas by Relativistic Electrons". The Astrophysical Journal. 222: 29. Bibcode:1978ApJ...222...29L. doi:10.1086/156118.
  30. ^ Scott, J. S.; Holman, G. D.; Ionson, J. A.; Papadopoulos, K. (1980). "The Heating of Gas in Clusters of Galaxies by Relativistic Electrons: Collective Effects". The Astrophysical Journal. 239: 769. Bibcode:1980ApJ...239..769S. doi:10.1086/158162.
  31. ^ Wentzel, D. G. (1974). "Cosmic-ray propagation in the Galaxy: collective effects". Annual Review of Astronomy and Astrophysics. 12: 71. Bibcode:1974ARA&A..12...71W. doi:10.1146/annurev.aa.12.090174.000443. Retrieved 2023-04-14.
  32. ^ Jaffe, W. J. (1977). "Origin and transport of electrons in the halo radio source in the Coma cluster". The Astrophysical Journal. 212 (212): 1–7. Bibcode:1977ApJ...212....1J. doi:10.1086/155011.
  33. ^ Holman, G.D.; Ionson, J. A.; Scott, J. S. (1979). "Particle Streaming: Is the Alfven Velocity the Ultimate Speed Limit?". The Astrophysical Journal. 228: 576. Bibcode:1979ApJ...228..576H. doi:10.1086/156881.
  34. ^ Slottje, C. (1978). "Millisecond microwave spikes in a solar flare". Nature. 275 (5680): 520–521. Bibcode:1978Natur.275..520S. doi:10.1038/275520a0. S2CID 4164792.
  35. ^ Holman, G. D.; Eichler, D.; Kundu, M. R. (1980). "An Interpretation of Solar Flare Microwave Spikes as Gyrosynchrotron Masering". In Kundu, M. R.; Gergely, T. E. (eds.). Radio Physics of the Sun. Vol. 86. Dordrecht: Reidel. pp. 457–459. doi:10.1007/978-94-010-9722-2_65 (inactive 1 November 2024). ISBN 978-90-277-1121-2.{{cite book}}: CS1 maint: DOI inactive as of November 2024 (link)
  36. ^ Holman, G. D.; Bookbinder, J.; Golub, L. (1985). "Implications of the 1400 MHZ Flare Emission from AD Leo for the Emission Mechanism and Flare Environment". In Hjellming, R. M.; Gibson, D.M. (eds.). Radio Stars. Astrophysics and Space Science Library. Vol. 116. Dordrecht: Reidel. pp. 35–37. Bibcode:1985ASSL..116...35H. doi:10.1007/978-94-009-5420-5_3. ISBN 978-94-010-8892-3.
  37. ^ "Sun-Earth Connection". Solar Flare Theory Educational Web Pages. Retrieved 2023-04-14.
  38. ^ Holman, G. D.; Pesses, M. E. (1983). "Solar Type II Radio Emission and the Shock Drift Acceleration of Electrons". The Astrophysical Journal. 267: 837. Bibcode:1983ApJ...267..837H. doi:10.1086/160918.
  39. ^ Aurass, H.; Holman, G.; Braune, S.; Mann, G.; Zlobec, P. (2013). "Radio evidence for breakout reconnection in solar eruptive events". Astronomy and Astrophysics. 555: A40. Bibcode:2013A&A...555A..40A. doi:10.1051/0004-6361/201321111.
  40. ^ Chrysaphi, Nicolina; Kontar, Eduard P.; Holman, Gordon D.; Temmer, Manuela (2018). "CME-driven Shock and Type II Solar Radio Burst Band Splitting". The Astrophysical Journal. 868 (2): 79. arXiv:1810.08026. Bibcode:2018ApJ...868...79C. doi:10.3847/1538-4357/aae9e5. S2CID 53395062.
  41. ^ "Solar Flares". Solar Flare Theory Educational Web Pages. Retrieved 2023-04-14.
  42. ^ "Adi Foord".
  43. ^ Holman, Gordon D.; Foord, Adi (2015). "Direct Spatial Association of an X-Ray Flare with the Eruption of a Solar Quiescent Filament". The Astrophysical Journal. 804 (2): 108. Bibcode:2015ApJ...804..108H. doi:10.1088/0004-637X/804/2/108. S2CID 124233139.
  44. ^ "Exploring Magnetism in Solar Flares – session 4". cse.ssl.berkeley.edu. Retrieved 2023-04-16.
  45. ^ Holman, Gordon D.; Kundu, Mukul R. (1985). "The microwave structure of hot coronal loops". The Astrophysical Journal. 292: 291–296. Bibcode:1985ApJ...292..291H. doi:10.1086/163159 – via NASA ADS.
  46. ^ Schmelz, J. T.; Holman, G. D. (1991). "Results from CoMStOC: The coronal magnetic structures observing campaign". Advances in Space Research. 11 (1): 109–116. Bibcode:1991AdSpR..11a.109S. doi:10.1016/0273-1177(91)90099-6.
  47. ^ Brosius, Jeffrey W.; Holman, Gordon D.; Schmelz, Joan T. (15 October 1991). "EOS Science News by AGU: Microwave polarization inversion observed". Eos: Science News by AGU. 72 (42): 449–454. doi:10.1029/90EO00328.
  48. ^ Holman, G. D. (1994). Balasubramaniam, K. S.; Simon, G. W. (eds.). "Coronal Structures in Active Regions: Quantitative Results from Multi-Wavelength Observations and Comparisons with Models". Solar Active Region Evolution: Comparing Models with Observations (Proceedings of the XIVth NSO/Sacramento Peak Summer Workshop). 68: 356. Bibcode:1994ASPC...68..356H.
  49. ^ Holman, G. D.; Cheng, C.-C.; Gurman, J. B.; Haisch, B. M.; Poland, A. I.; Porter, J. G.; Saba, J. L. R.; Schmieder, B.; Strong, K. T. (1999). Strong, K. T.; Saba, J. L. R.; Haisch, B. M.; Schmelz, J. T. (eds.). "Active Regions". The Many Faces of the Sun: A Summary of the Results from NASA's Solar Maximum Mission. Springer-Verlag: 41. Bibcode:1999mfs..conf...41H.
  50. ^ Phillips, Dr Tony (2021-12-28). "A Disconnection Event in the Tail of Comet Leonard". Spaceweather.com. Retrieved 2023-04-16.
  51. ^ Jia, Ying-Dong; Combi, Michael R.; Hansen, Kenneth C.; Gombosi, Tamas I. (May 2007). "A global model of cometary tail disconnection events triggered by solar wind magnetic variations: MHD MODEL OF COMET DE". Journal of Geophysical Research: Space Physics. 112 (A5): n/a. doi:10.1029/2006JA012175. hdl:2027.42/94832.
  52. ^ Yeomans, D. K.; Brandt, J. C. (1985-01-01). The comet Giacobini-Zinner handbook. An observer's guide to the first comet to be explored by a spacecraft. Bibcode:1985cgha.book.....Y.
  53. ^ "The Comet Giacobini-Zinner handbook : an observer's guide to the first comet to be explored by a spacecraft, February 14, 1985 / created by Donald K. Yeomans ..." HathiTrust. hdl:2027/uva.x004195091. Retrieved 2023-08-15.
  54. ^ Brosius, J. W.; Holman, G. D.; Niedner, M. B.; Brandt, J. C.; Slavin, J. A.; Smith, E. J.; Zwickl, R. D.; Bame, S. J. (1987). "On the Cause of Plasma Tail Disconnection Events in Comet Halley During the ICE- Halley Radial Period". Astronomy and Astrophysics. 187: 267.
  55. ^ "Interview with Brian Dennis and Gordon Holman: NASA's Sun-Earth Day". Archive.org (Audio Podcast). 14 March 2011.
  56. ^ "RHESSI Web Site". hesperia.gsfc.nasa.gov. Retrieved 2023-04-15.
  57. ^ Sui, Linhui; Holman, Gordon D.; Dennis, Brian R.; Krucker, Sam; Schwartz, Richard A.; Tolbert, Kim (2002). "Modeling Images and Spectra of a Solar Flare Observed by RHESSI on 20 February 2002". Solar Physics. 210 (1): 245–259. Bibcode:2002SoPh..210..245S. doi:10.1023/A:1022417832283. S2CID 117196829.
  58. ^ Holman, Gordon D.; Sui, Linhui; Schwartz, Richard A.; Emslie, A. Gordon (2003). "Electron Bremsstrahlung Hard X-Ray Spectra, Electron Distributions, and Energetics in the 2002 July 23 Solar Flare". The Astrophysical Journal. 595 (2): L97–L101. Bibcode:2003ApJ...595L..97H. doi:10.1086/378488. S2CID 56240913.
  59. ^ Emslie, A. G.; et al. (2004). "Energy partition in two solar flare/CME events". Journal of Geophysical Research: Space Physics. 109 (A10): A10104. Bibcode:2004JGRA..10910104E. doi:10.1029/2004JA010571. hdl:2027.42/95583.
  60. ^ Emslie, A. G.; Dennis, B. R.; Holman, G. D.; Hudson, H. S. (2005). "Refinements to flare energy estimates: A followup to Energy partition in two solar flare/CME events by A. G. Emslie et al". Journal of Geophysical Research: Space Physics. 110 (A11): A11103. Bibcode:2005JGRA..11011103E. doi:10.1029/2005JA011305.
  61. ^ Aschwanden, Markus J.; et al. (2019). "Global Energetics of Solar Flares and Coronal Mass Ejections". Journal of Physics: Conference Series. 1332 (1): 012002. Bibcode:2019JPhCS1332a2002A. doi:10.1088/1742-6596/1332/1/012002. S2CID 209934624.
  62. ^ "Coronal Mass Ejections, Solar Flares, and the Sun-Earth Connection". Solar Flare Theory Educational Web Pages.
  63. ^ Sui, Linhui; Holman, Gordon D. (2003). "Evidence for the Formation of a Large-Scale Current Sheet in a Solar Flare". The Astrophysical Journal. 596 (2): L251–L254. Bibcode:2003ApJ...596L.251S. doi:10.1086/379343. S2CID 120173304.
  64. ^ Sui, Linhui; Holman, Gordon D; Dennis, Brian R. (2004). "Evidence for Magnetic Reconnection in Three Homologous Solar Flares Observed by RHESSI". The Astrophysical Journal. 612 (1): 546–556. Bibcode:2004ApJ...612..546S. doi:10.1086/422515. S2CID 53982160.
  65. ^ Savage, Sabrina L.; Holman, Gordon; Reeves, Katharine K.; Seaton, Daniel B.; McKenzie, David E.; Su, Yang (2012). "Low-altitude Reconnection Inflow-Outflow Observations during a 2010 November 3 Solar Eruption". The Astrophysical Journal. 754 (1): 13. arXiv:1111.1945. Bibcode:2012ApJ...754...13S. doi:10.1088/0004-637X/754/1/13. S2CID 54750353.
  66. ^ Su, Yang; Veronig, Astrid M.; Holman, Gordon D.; Dennis, Brian R.; Wang, Tongjiang; Temmer, Manuela; Gan, Waiqun (2013). "Imaging coronal magnetic-field reconnection in a solar flare". Nature Physics. 9 (8): 489–493. arXiv:1307.4527. Bibcode:2013NatPh...9..489S. doi:10.1038/nphys2675. S2CID 119226120.
  67. ^ "A Flaring Loop at the Solar Limb as Seen by Yohkoh". Solar Flare Theory Educational Web Pages.
  68. ^ Holman, Gordon D. (2012). "Understanding the Impact of Return-current Losses on the X-Ray Emission from Solar Flares". The Astrophysical Journal. 745 (1): 52. Bibcode:2012ApJ...745...52H. doi:10.1088/0004-637X/745/1/52. hdl:2060/20120008262. S2CID 120586153.
  69. ^ "Meriem Alaoui Abdallaoui".
  70. ^ "Early Career Scientist Spotlight – Meriem Alaoui Abdallaoui".
  71. ^ Alaoui, Meriem; Holman, Gordon D. (2017). "Understanding Breaks in Flare X-Ray Spectra: Evaluation of a Cospatial Collisional Return-current Model". The Astrophysical Journal. 851 (2): 78. arXiv:1706.03897. Bibcode:2017ApJ...851...78A. doi:10.3847/1538-4357/aa98de. S2CID 126138492.
  72. ^ Alaoui, Meriem; Holman, Gordon D.; Allred, Joel C.; Eufrasio, Rafael T. (2021). "Role of Suprathermal Runaway Electrons Returning to the Acceleration Region in Solar Flares". The Astrophysical Journal. 917 (2): 74. arXiv:2103.13999. Bibcode:2021ApJ...917...74A. doi:10.3847/1538-4357/ac0820. S2CID 232352553.
  73. ^ Benz, A. O.; et al. (1994). "Particle Acceleration in Flares". Solar Physics. 153 (1–2): 33–53. Bibcode:1994SoPh..153...33B. doi:10.1007/BF00712491. S2CID 16744095.
  74. ^ Miller, James A.; et al. (1997). "Critical issues for understanding particle acceleration in impulsive solar flares". Journal of Geophysical Research. 102 (A7): 14631–14660. Bibcode:1997JGR...10214631M. doi:10.1029/97JA00976. S2CID 36824157.
  75. ^ Holman, G. D.; et al. (2011). "Implications of X-ray Observations for Electron Acceleration and Propagation in Solar Flares". Space Science Reviews. 159 (1–4): 107–166. arXiv:1109.6496. Bibcode:2011SSRv..159..107H. doi:10.1007/s11214-010-9680-9. S2CID 52242510.
  76. ^ Kontar, E. P.; et al. (2011). "Deducing Electron Properties from Hard X-ray Observations". Space Science Reviews. 159 (1–4): 301–355. arXiv:1110.1755. Bibcode:2011SSRv..159..301K. doi:10.1007/s11214-011-9804-x. S2CID 55797275.
  77. ^ Holman, Gordon D. (2016). "Scientific considerations for future spectroscopic measurements from space of activity on the Sun". Journal of Geophysical Research: Space Physics. 121 (12): 11, 667–11, 697. Bibcode:2016JGRA..12111667H. doi:10.1002/2016JA022651. S2CID 126213071.
  78. ^
    Citation to 2018 NASA Exceptional Scientific Achievement Medal awarded to Gordon D. Holman
  79. ^
    2013 NASA Group Achievement Award
    NASA Group Achievement Award, awarded to the RHESSI Science and Data Analysis Team in 2013
  80. ^ "SPD Popular Media Awards".
  81. ^
    G. Holman 2014: Who's Who in the World
    Gordon D. Holman 2014 Who's Who in the World Biography
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