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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"

11618 results found.

  1. GRB 250821B: Fermi GBM Detection
  2. GRB 250821B: BALROG localization (Fermi Trigger / GRB 250821672)
  3. GRB 250821B: Fermi GBM Final Localization of a Bright Burst
  4. GRB 250814A: CMO SAI and SAO RAS izJ observations.
  5. IPN triangulation of GRB 250816A (short)
  6. LIGO/Virgo/KAGRA S250818k: Upper limits from Fermi-GBM Observations
  7. GRB 250818A: AstroSat CZTI detection
  8. Fermi Gamma-ray Burst Monitor trigger 777342746/250820022 is not a GRB
  9. GRB 250820A: Fermi GBM Final Real-time Localization
  10. Fermi GRB 250816A: Global MASTER-Net observations report
  11. Fermi Gamma-ray Burst Monitor trigger 777251788/250818970 is not a GRB
  12. GRB 250818C: Fermi GBM Final Real-time Localization
  13. Fermi trigger No 776849714: Global MASTER-Net observations report
  14. GRB 250813B: SVOM/ECLAIRs refined analysis
  15. GRB 250818A: Fermi GBM Observation
  16. GRB 250814A: Further GRAWITA TNG NIR observations
  17. GRB 250818A: Fermi GBM Final Real-time Localization
  18. GRB 250816A: SVOM/GRM observation of a short burst
  19. Fermi GRB 250814B: Global MASTER-Net observations report
  20. GRB 250816A: Fermi GBM Final Real-time Localization
  21. GRB 250815A: Fermi GBM Final Localization
  22. GRB 250813B: Liverpool Telescope optical upper limits
  23. GRB 250814A: Further COLIBRÍ optical upper limit
  24. GRB 250814A: detection of the afterglow candidate with Liverpool Telescope
  25. GRB 250814A: GRAWITA TNG NIR observations
  26. GRB 250814A: Mondy optical observations of the candidate counterpart to LVK S250814bg
  27. GRB250814A: TRT optical upper limits
  28. GRB 250814B: SVOM/GRM observation
  29. GRB 250813B: SVOM/GRM observation
  30. GRB 250814A: P200/WIRC observations of the afterglow candidate
  31. GRB 250814A: possible optical afterglow candidate at Spanish observatories
  32. GRB 250814A: KAIT optical upper limit
  33. GRB 240814A: Fermi GBM Observation
  34. GRB 250814A: Possible afterglow candidate from P200/WIRC
  35. GRB 250813B: Fermi GBM Observation
  36. GRB 250814A: Optical observations with MDM Hiltner 2.4m telescope
  37. Fermi trigger No 776818276: Global MASTER-Net observations report
  38. GRB 250814A: J-band upper limit from WINTER
  39. GRB 250814A: COLIBRÍ optical upper limit
  40. GRB 250814B: Fermi GBM Final Real-time Localization
  41. GRB 250813A: AstroSat CZTI detection
  42. LIGO/Virgo/KAGRA S250814bg: Identification of a GW compact binary merger candidate possibly associated with GRB 250814A detected by Fermi GBM and Swift BAT
  43. Fermi-LAT Gamma-ray Observations of IceCube-250813A
  44. GRB 250814A: Fermi GBM Final Real-time Localization
  45. GRB 250813A: Fermi GBM Final Localization
  46. IceCube-250813A - IceCube observation of a high-energy neutrino candidate track-like event
  47. Fermi Gamma-ray Burst Monitor trigger 776705265/250812644 is not a GRB
  48. Fermi Gamma-ray Burst Monitor trigger 776620220/250811660 is not a GRB
  49. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  50. GRB 250702B: Chandra X-ray Detection
  51. Fermi GRB 250808A: Global MASTER-Net observations report
  52. Fermi Gamma-ray Burst Monitor trigger 776449964/250809689 is not a GRB
  53. GRB 250808A: Fermi GBM Observation
  54. GRB 250808A: SVOM detection of a long burst
  55. GRB 250808A: Fermi GBM Final Real-time Localization
  56. EP250806a: Upper limit from Fermi-GBM Observations
  57. GRB 250804C: AstroSat CZTI detection of a long burst
  58. IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
  59. Fermi trigger No 776041355: Global MASTER-Net observations report
  60. GRB 250804A: Fermi GBM Final Localization
  61. Fermi Gamma-ray Burst Monitor trigger 775945985/250803856 is not a GRB
  62. GRB 250725A: AstroSat CZTI detection
  63. GRB 250725A: PRIME near-infrared observations
  64. GRB 250728A: Swift-XRT observations
  65. GRB 250728A: COLIBRÍ optical upper limit
  66. GRB 250728A: Fermi GBM Observation
  67. Fermi trigger No 775387550: Global MASTER-Net observations report
  68. GRB 250728A: Swift ToO observations
  69. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst
  70. GRB 250725A: Fermi GBM Observation
  71. Konus-Wind detection of GRB 250725A
  72. GRB 250725A: SVOM/GRM observation
  73. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  74. GRB 250725A: Fermi-LAT detection
  75. GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
  76. GRB 250725A: SVOM/VT optical candidate
  77. GRB 250725A: Fermi GBM Final Real-time Localization
  78. Fermi GRB 250725A: Global MASTER-Net observations report
  79. GRB 250723B: Fermi GBM Final Real-time Localization
  80. GRB 250721A: Fermi GBM Observation
  81. GRB 250723A: Fermi GBM Final Real-time Localization
  82. GRB 250722A: Fermi GBM Final Real-time Localization
  83. GRB 250717B: SVOM/GRM observation
  84. GRB 250721A: MAXI/GSC detection
  85. GRB 250721A: Fermi GBM Final Localization
  86. GRB 250720B: Fermi GBM Final Localization Correction
  87. GRB 250720A: Fermi GBM Final Localization
  88. Fermi trigger No 774730635: Global MASTER-Net observations report
  89. LIGO/Virgo/KAGRA S250720j: Retraction of GW compact binary merger candidate
  90. Fermi Gamma-ray Burst Monitor trigger 774670514/250720094 is not a GRB
  91. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  92. GRB 250717B: COLIBRÍ optical upper limit
  93. GRB 250717B: Swift-XRT observations
  94. GRB 250718B: Fermi GBM Final Localization Correction
  95. GRB 250718B: Fermi GBM Final Real-time Localization
  96. GRB 250717B: Swift ToO observations
  97. GRB 250717B: Fermi GBM Observation
  98. GRB 250717B: Swift/BAT-GUANO arcminute localization of a burst
  99. Konus-Wind detection of GRB 250716A
  100. GRB 250716A: Swift-XRT afterglow detection

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