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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"
  1. IceCube-200911A: not observable by Fermi-GBM
  2. IceCube-200911A: IceCube observation of a high-energy neutrino candidate event
  3. GRB 200826A: uGMRT radio upper limit at 1.25 GHz
  4. IPN triangulation of GRB 200907A (short)
  5. GRB 200909B: Swift-BAT refined analysis
  6. Swift GRB200909.97: Global MASTER-Net observations report
  7. GRB 200909B: Swift detection of a burst
  8. GRB 200909A: AstroSat CZTI detection
  9. GRB 200829A: T100 observations
  10. Fermi GRB 200909A: Global MASTER-Net observations report
  11. GRB 200909A: BALROG localization (Fermi Trigger 621316887 / GRB 200909168)
  12. GRB 200909A: Fermi GBM Final Real-time Localization
  13. GRB 200907B: Swift/UVOT Upper Limits
  14. Fermi GRB 200908A: Global MASTER-Net observations report
  15. GRB 200907B: Swift-BAT refined analysis
  16. Konus-Wind detection of GRB 200903E
  17. GRB 200908A: Fermi GBM Final Real-time Localization
  18. GRB 200907B: AstroSat CZTI detection
  19. GRB 200907B: Swift-XRT refined Analysis
  20. GRB 200907B: MITSuME Okayama optical upper limits
  21. Swift GRB 200907B: Global MASTER-Net observations report
  22. GRB 200907B: Enhanced Swift-XRT position
  23. Fermi GRB 200907C: Global MASTER-Net observations report
  24. GRB 200907C: Fermi GBM Final Real-time Localization
  25. Correction to GCN 28387: GRB 200907B GROWTH-India optical upper limit
  26. GRB200907A: GROWTH-India optical upper limit
  27. Fermi GRB 200906A: Global MASTER-Net observations report
  28. GRB 200907B: Prompt enhanced Swift-XRT position
  29. GRB 200907B: Swift detection of a short burst
  30. IPN triangulation of GRB 200903E
  31. GRB 200906A: EMIR/GTC NIR upper limit
  32. GRB 200906A: LBT near-infrared upper limit
  33. GRB 200906A: Swift-BAT refined analysis
  34. GRB 200906A: Swift/UVOT Upper Limits
  35. GRB 200907A: AGILE/MCAL detection of a burst
  36. GRB 200906A: GROWTH-India Telescope (GIT) optical r band upper limit
  37. GRB 200906A: OSN 1.5m Upper Limit
  38. GRB 200906A: Swift-XRT refined Analysis
  39. GRB 200906A: Fermi GBM detection
  40. GRB 200906A: Enhanced Swift-XRT position
  41. GRB 200906A: Nanshan/NEXT optical upper limit
  42. GRB 200906A: Swift detection of a burst
  43. GRB 200906A: Fermi GBM Final Real-time Localization
  44. Baksan Neutrino Observatory Alert 200905.99: Global MASTER-Net observations report
  45. Swift Triggers 994723-994725 and 994727 are not GRBs.
  46. GRB 200903E: AstroSat CZTI detection
  47. Fermi GRB 200904A: Global MASTER-Net observations report
  48. GRB 200904A: Fermi GBM Final Real-time Localization
  49. Fermi GRB 200903C: Global MASTER-Net observations report
  50. GRB 200903D: MAXI/GSC detection
  51. GRB 200903A: Fermi GBM detection
  52. GRB 200903C: Fermi GBM Final Real-time Localization
  53. GRB 200903A: Swift-BAT refined analysis
  54. GRB 200829A: optical observations, a light curve in R-filter
  55. GRB 200903B: Insight-HXMT/HE detection
  56. GRB 200903A: CALET Gamma-Ray Burst Monitor detection
  57. AGILE detection of a burst (AGILE trigger no. 526185273)
  58. ZTF20abtxwfx/AT2020sev : AstroSat CZTI non-detection of a transient
  59. GRB200817B: AstroSat CZTI detection
  60. Fermi GRB 200903B: Global MASTER-Net observations report
  61. GRB 200903B: Fermi GBM Final Real-time Localization
  62. Swift GRB200903.03: Global MASTER-Net observations report
  63. GRB 200903A: Swift detection of a burst
  64. GRB 200903A: Fermi GBM Final Real-time Localization
  65. GRB 200901A: MASTER OT early detection
  66. GRB 200901B: Swift-XRT refined Analysis
  67. INTEGRAL Weak#8699: AROMA-N Optical Observation
  68. GRB 200901B: Swift-BAT refined analysis
  69. GRB 200901A: Swift-BAT refined analysis
  70. GRB 200901B: Swift/UVOT Detection
  71. GRB 200901A: Swift/UVOT Detection
  72. GRB 200901A: Swift-XRT refined Analysis
  73. GRB 200901A: Fermi GBM observation
  74. GRB 200901B: Enhanced Swift-XRT position
  75. GRB 200829A: Swift/UVOT-XRT photometric redshift
  76. GRB 200901B: Swift detection of a burst
  77. GRB 200901A: Swift-XRT observations
  78. GRB 200901A: Swift detection of a burst
  79. Swift GRB200901.16: Global MASTER-Net observations report
  80. GRB 200829A: Koshka Zeiss-1000 optical observations
  81. Fermi GBM trigger 620564765/200831463 is not a GRB
  82. GRB 200829A: Liverpool Telescope observations
  83. GRB 200829A: Continued Nanshan/NEXT optical observations
  84. GRB 200829A: Kitab optical upper limit
  85. GRB 200829A: further SAO RAS optical observations
  86. Fermi GRB 200830A: Global MASTER-Net observations report
  87. GRB 200829A: Fermi GBM detection
  88. GRB 200829A: Swift-BAT refined analysis
  89. GRB 200829A: Nanshan/NEXT optical observations
  90. Konus-Wind detection of GRB 200829A (a clone of GRB 200826B?)
  91. GRB 200829A: SAO RAS optical observations
  92. GRB 200830A: BALROG localization (Fermi Trigger 620474063 / GRB 200830413)
  93. GRB 200830A: Fermi GBM Final Real-time Localization
  94. GRB 200826A
  95. GRB 200829A: THO optical observatios
  96. GRB 200829A: Swift-XRT refined Analysis
  97. GRB200829A: optical afterglow detection
  98. GRB 200829A: Global MASTER-Net OT detection
  99. GRB 200829A: AGILE/MCAL detection
  100. GRB 200829A: Enhanced Swift-XRT position

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