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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

3674 results found.

  1. Fermi GRB 210120A: Global MASTER-Net observations report
  2. Konus-Wind detection of GRB 210112A
  3. GRB 201227A: ASIM observation
  4. GW170817: HST observations at 3.4 years from merger
  5. GRB 210104A: early ATLAS detections of the bright afterglow
  6. GRB 210104A: 1.3m DFOT Optical Afterglow Detection
  7. GRB 210104A: MITSuME Akeno optical observation
  8. GRB 210104A: GWAC-F60A optical afterglow observations
  9. GRB 210104A: Swift detection of a burst with a bright optical counterpart
  10. Fermi GRB 210102C: Global MASTER-Net observations report
  11. MAXI GRB210102.38: Global MASTER-Net observations report
  12. Fermi trigger No 631119348: Global MASTER-Net observations report
  13. Fermi trigger No 631113166: Global MASTER-Net observations report
  14. Fermi trigger No 631118376: Global MASTER-Net observations report
  15. GRB 201216C: TSHAO, Terskol, Mondy optical upper limits
  16. GRB 201227A: Chilescope optical observations, possible optical counterpart
  17. GRB 201227A: GRAWITA VST-ESO PARANAL observations
  18. GRB 201227A: Swift-XRT observations
  19. Konus-Wind observation of GRB 201227A
  20. Baksan Neutrino Observatory Alert 201228.36: Global MASTER-Net observations report
  21. Fermi GRB 201228B: Global MASTER-Net observations report
  22. GRB 201228B: Fermi GBM Final Real-time Localization
  23. GRB 201228A: Fermi GBM Final Real-time Localization
  24. Fermi trigger No 630389391: Global MASTER-Net observations report
  25. Fermi GRB 201222B: Global MASTER-Net observations report
  26. GRB 201221D: Lowell Discovery Telescope afterglow observations
  27. GRB 201221E: Fermi GBM Final Real-time Localization
  28. Fermi GBM Sub-Threshold Detection of GRB 201221A
  29. Konus-Wind detection of GRB 201216C
  30. Baksan Neutrino Observatory Alert 201216.94: Global MASTER-Net observations report
  31. Fermi GRB 201216A: Global MASTER-Net observations report
  32. GRB 201215A: BALROG localization (Fermi Trigger 629706213 / GRB 201215266)
  33. GRB 201215A: Fermi GBM Final Real-time Localization
  34. Integral GRB201214.26: Global MASTER-Net observations report
  35. GRB 201208A: LCO observations
  36. GRB201130A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 628407054)
  37. GRB 201128B: Swift/BAT-GUANO detection and arcminute localization
  38. IceCube Alert 201130.85: Global MASTER-Net observations report
  39. GRB 201130A: DDOTI Observations
  40. Fermi trigger No 628278856: Global MASTER-Net observations report
  41. GRB 201128A: DDOTI Observations
  42. GRB 200826A: TNG and LBT constraints on a supernova bump
  43. Fermi GRB 201121A: Global MASTER-Net observations report
  44. Fermi GRB 201120B: Global MASTER-Net observations report
  45. INTEGRAL Weak#8825: AROMA-N Optical Observation
  46. Konus-Wind detection of GRB 201116A
  47. Fermi trigger No 627198169: Global MASTER-Net observations report
  48. GRB 201114A: AstroSat CZTI detection
  49. GRB 201108A: Fermi GBM Final Real-time Localization
  50. ZTF20acozryr/AT2020yxz (GRB 201103B): Assy optical observations
  51. GRB 201104B: Kitab optical observations
  52. GRB 201103B (ZTF20acozryr/AT2020yxz): Nanshan/NEXT-0.6m optical observations
  53. ZTF20acozryr/AT2020yxz: Zwicky Transient Facility discovery of a fast optical transient with no associated GRB
  54. GRB 201029A: Swift-BAT refined analysis
  55. GRB 201024A: Redshift from GTC/OSIRIS
  56. Swift GRB201024.12: Global MASTER-Net observations report
  57. GRB 201020B: Nanshan/NEXT optical afterglow confirmation
  58. GRB 201020A: DOAO optical afterglow observations
  59. GRB 201020A: MITSuME Akeno optical observation
  60. IceCube-201014A: No significant detection in HAWC
  61. Fermi GRB 201016B: Global MASTER-Net observations report
  62. Fermi GRB 201007A: Global MASTER-Net observations report
  63. Baksan Neutrino Observatory Alert 201006.88: Global MASTER-Net observations report
  64. Fermi trigger No 623470566: Global MASTER-Net observations report
  65. Fermi trigger No 623493962: Global MASTER-Net observations report
  66. IceCube-200926A: JCMT/SCUBA2 observations
  67. IceCube-200929A: Upper limits from a search for additional neutrino events in IceCube
  68. GRB 200928B: AstroSat CZTI detection
  69. GRB 200928B: BALROG localization (Fermi Trigger 622991684 / GRB 200928552)
  70. GRB 200928B: Fermi GBM Final Real-time Localization
  71. GRB 200928A: Fermi GBM Final Localization
  72. Fermi GRB 200925A: Global MASTER-Net observations report
  73. Fermi GRB 200924A: Global MASTER-Net observations report
  74. GRB 200924B: Fermi GBM Final Localization
  75. Fermi trigger No 622618714: Global MASTER-Net observations report
  76. Fermi GRB 200923A: Global MASTER-Net observations report
  77. Fermi GRB 200922B: Global MASTER-Net observations report
  78. Fermi-GBM Sub-Threshold Detection of GRB 200917A
  79. GRB 200917A: Swift detection of a burst
  80. GRB 200916A: Fermi GBM Final Real-time Localization
  81. Fermi GRB 200914A: Global MASTER-Net observations report
  82. IceCube Alert 200914.00: Global MASTER-Net observations report
  83. Swift GRB200909.97: Global MASTER-Net observations report
  84. Fermi GRB 200907C: Global MASTER-Net observations report
  85. GRB 200907C: Fermi GBM Final Real-time Localization
  86. Fermi GRB 200906A: Global MASTER-Net observations report
  87. IPN triangulation of GRB 200903E
  88. Fermi GRB 200903B: Global MASTER-Net observations report
  89. GRB 200829A: Continued Nanshan/NEXT optical observations
  90. GRB 200826A
  91. Fermi trigger No 620402299: Global MASTER-Net observations report
  92. IPN triangulation of GRB 200826B
  93. Swift Trigger 992444: a possible GRB 200821A
  94. Fermi trigger No 619270776: Global MASTER-Net observations report
  95. IceCube200806A: No significant detection in HAWC
  96. GRB 200809B: MAXI/GSC detection
  97. GRB 200806A: CALET Gamma-Ray Burst Monitor detection
  98. IPN triangulation of GRB 200805A (short)
  99. Swift GRB 200806A: Global MASTER-Net observations report
  100. GRB 200806A: Swift detection of a burst

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