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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

11622 results found.

  1. IPN triangulation of GRB 250821B (long/bright)
  2. GRB 250821B: SVOM/GRM observation
  3. Fermi GRB 250821B: Global MASTER-Net observations report
  4. GRB 250821C: Fermi GBM Final Real-time Localization
  5. GRB 250821B: Fermi GBM Detection
  6. GRB 250821B: BALROG localization (Fermi Trigger / GRB 250821672)
  7. GRB 250821B: Fermi GBM Final Localization of a Bright Burst
  8. GRB 250814A: CMO SAI and SAO RAS izJ observations.
  9. IPN triangulation of GRB 250816A (short)
  10. LIGO/Virgo/KAGRA S250818k: Upper limits from Fermi-GBM Observations
  11. GRB 250818A: AstroSat CZTI detection
  12. Fermi Gamma-ray Burst Monitor trigger 777342746/250820022 is not a GRB
  13. GRB 250820A: Fermi GBM Final Real-time Localization
  14. Fermi GRB 250816A: Global MASTER-Net observations report
  15. Fermi Gamma-ray Burst Monitor trigger 777251788/250818970 is not a GRB
  16. GRB 250818C: Fermi GBM Final Real-time Localization
  17. Fermi trigger No 776849714: Global MASTER-Net observations report
  18. GRB 250813B: SVOM/ECLAIRs refined analysis
  19. GRB 250818A: Fermi GBM Observation
  20. GRB 250814A: Further GRAWITA TNG NIR observations
  21. GRB 250818A: Fermi GBM Final Real-time Localization
  22. GRB 250816A: SVOM/GRM observation of a short burst
  23. Fermi GRB 250814B: Global MASTER-Net observations report
  24. GRB 250816A: Fermi GBM Final Real-time Localization
  25. GRB 250815A: Fermi GBM Final Localization
  26. GRB 250813B: Liverpool Telescope optical upper limits
  27. GRB 250814A: Further COLIBRÍ optical upper limit
  28. GRB 250814A: detection of the afterglow candidate with Liverpool Telescope
  29. GRB 250814A: GRAWITA TNG NIR observations
  30. GRB 250814A: Mondy optical observations of the candidate counterpart to LVK S250814bg
  31. GRB250814A: TRT optical upper limits
  32. GRB 250814B: SVOM/GRM observation
  33. GRB 250813B: SVOM/GRM observation
  34. GRB 250814A: P200/WIRC observations of the afterglow candidate
  35. GRB 250814A: possible optical afterglow candidate at Spanish observatories
  36. GRB 250814A: KAIT optical upper limit
  37. GRB 240814A: Fermi GBM Observation
  38. GRB 250814A: Possible afterglow candidate from P200/WIRC
  39. GRB 250813B: Fermi GBM Observation
  40. GRB 250814A: Optical observations with MDM Hiltner 2.4m telescope
  41. Fermi trigger No 776818276: Global MASTER-Net observations report
  42. GRB 250814A: J-band upper limit from WINTER
  43. GRB 250814A: COLIBRÍ optical upper limit
  44. GRB 250814B: Fermi GBM Final Real-time Localization
  45. GRB 250813A: AstroSat CZTI detection
  46. LIGO/Virgo/KAGRA S250814bg: Identification of a GW compact binary merger candidate possibly associated with GRB 250814A detected by Fermi GBM and Swift BAT
  47. Fermi-LAT Gamma-ray Observations of IceCube-250813A
  48. GRB 250814A: Fermi GBM Final Real-time Localization
  49. GRB 250813A: Fermi GBM Final Localization
  50. IceCube-250813A - IceCube observation of a high-energy neutrino candidate track-like event
  51. Fermi Gamma-ray Burst Monitor trigger 776705265/250812644 is not a GRB
  52. Fermi Gamma-ray Burst Monitor trigger 776620220/250811660 is not a GRB
  53. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  54. GRB 250702B: Chandra X-ray Detection
  55. Fermi GRB 250808A: Global MASTER-Net observations report
  56. Fermi Gamma-ray Burst Monitor trigger 776449964/250809689 is not a GRB
  57. GRB 250808A: Fermi GBM Observation
  58. GRB 250808A: SVOM detection of a long burst
  59. GRB 250808A: Fermi GBM Final Real-time Localization
  60. EP250806a: Upper limit from Fermi-GBM Observations
  61. GRB 250804C: AstroSat CZTI detection of a long burst
  62. IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
  63. Fermi trigger No 776041355: Global MASTER-Net observations report
  64. GRB 250804A: Fermi GBM Final Localization
  65. Fermi Gamma-ray Burst Monitor trigger 775945985/250803856 is not a GRB
  66. GRB 250725A: AstroSat CZTI detection
  67. GRB 250725A: PRIME near-infrared observations
  68. GRB 250728A: Swift-XRT observations
  69. GRB 250728A: COLIBRÍ optical upper limit
  70. GRB 250728A: Fermi GBM Observation
  71. Fermi trigger No 775387550: Global MASTER-Net observations report
  72. GRB 250728A: Swift ToO observations
  73. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
  74. GRB 250725A: Fermi GBM Observation
  75. Konus-Wind detection of GRB 250725A
  76. GRB 250725A: SVOM/GRM observation
  77. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  78. GRB 250725A: Fermi-LAT detection
  79. GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
  80. GRB 250725A: SVOM/VT optical candidate
  81. GRB 250725A: Fermi GBM Final Real-time Localization
  82. Fermi GRB 250725A: Global MASTER-Net observations report
  83. GRB 250723B: Fermi GBM Final Real-time Localization
  84. GRB 250721A: Fermi GBM Observation
  85. GRB 250723A: Fermi GBM Final Real-time Localization
  86. GRB 250722A: Fermi GBM Final Real-time Localization
  87. GRB 250717B: SVOM/GRM observation
  88. GRB 250721A: MAXI/GSC detection
  89. GRB 250721A: Fermi GBM Final Localization
  90. GRB 250720B: Fermi GBM Final Localization Correction
  91. GRB 250720A: Fermi GBM Final Localization
  92. Fermi trigger No 774730635: Global MASTER-Net observations report
  93. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  94. Fermi Gamma-ray Burst Monitor trigger 774670514/250720094 is not a GRB
  95. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  96. GRB 250717B: COLIBRÍ optical upper limit
  97. GRB 250717B: Swift-XRT observations
  98. GRB 250718B: Fermi GBM Final Localization Correction
  99. GRB 250718B: Fermi GBM Final Real-time Localization
  100. GRB 250717B: Swift ToO observations

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