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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"

11649 results found.

  1. GRB 250902B: Fermi GBM Final Real-time Localization
  2. GRB 250902A: SVOM/GRM observation
  3. GRB 250902A: Fermi GBM Final Real-time Localization
  4. IceCube-250831A - IceCube observation of a high-energy neutrino candidate track-like event
  5. LIGO/Virgo/KAGRA S250725j: Observations with the NSF-DOE Vera C. Rubin Observatory
  6. GRB 250828A: Fermi GBM Final Localization
  7. GRID detection of GRB 250824A
  8. Fermi GRB 250827A: Global MASTER-Net observations report
  9. GRB 250826A: SVOM/GRM observation
  10. GRB 250827A: Fermi GBM Final Real-time Localization
  11. Fermi GRB 250826A: Global MASTER-Net observations report
  12. Fermi trigger No 777883624: Global MASTER-Net observations report
  13. Fermi Gamma-ray Burst Monitor trigger 777883624/250826283 is not a GRB
  14. GRB 250826A: Fermi GBM Final Real-time Localization
  15. Fermi GRB 250824B: Global MASTER-Net observations report
  16. GRB 250821B: AstroSat CZTI detection
  17. GRB 250821B: Insight-HXMT detection
  18. GRB 250824B: Fermi GBM Final Real-time Localization
  19. GRB 250823A: COLIBRÍ optical observations
  20. GRB 250823A: SVOM/VT optical observation
  21. GRB 250824A: Fermi GBM Final Real-time Localization
  22. GRB 250823A: NOT optical observations
  23. GRB 250823A: Fermi GBM Observation
  24. GRB 250823A: BOOTES6/DPRT early optical detection
  25. GRB 250823A: Liverpool Telescope optical detection
  26. GRB 250823A: Fermi GBM Final Real-time Localization
  27. Konus-Wind detection of GRB 250821B
  28. IPN triangulation of GRB 250821B (long/bright)
  29. GRB 250821B: SVOM/GRM observation
  30. Fermi GRB 250821B: Global MASTER-Net observations report
  31. GRB 250821C: Fermi GBM Final Real-time Localization
  32. GRB 250821B: Fermi GBM Detection
  33. GRB 250821B: BALROG localization (Fermi Trigger / GRB 250821672)
  34. GRB 250821B: Fermi GBM Final Localization of a Bright Burst
  35. GRB 250814A: CMO SAI and SAO RAS izJ observations.
  36. IPN triangulation of GRB 250816A (short)
  37. LIGO/Virgo/KAGRA S250818k: Upper limits from Fermi-GBM Observations
  38. GRB 250818A: AstroSat CZTI detection
  39. Fermi Gamma-ray Burst Monitor trigger 777342746/250820022 is not a GRB
  40. GRB 250820A: Fermi GBM Final Real-time Localization
  41. Fermi GRB 250816A: Global MASTER-Net observations report
  42. Fermi Gamma-ray Burst Monitor trigger 777251788/250818970 is not a GRB
  43. GRB 250818C: Fermi GBM Final Real-time Localization
  44. Fermi trigger No 776849714: Global MASTER-Net observations report
  45. GRB 250813B: SVOM/ECLAIRs refined analysis
  46. GRB 250818A: Fermi GBM Observation
  47. GRB 250814A: Further GRAWITA TNG NIR observations
  48. GRB 250818A: Fermi GBM Final Real-time Localization
  49. GRB 250816A: SVOM/GRM observation of a short burst
  50. Fermi GRB 250814B: Global MASTER-Net observations report
  51. GRB 250816A: Fermi GBM Final Real-time Localization
  52. GRB 250815A: Fermi GBM Final Localization
  53. GRB 250813B: Liverpool Telescope optical upper limits
  54. GRB 250814A: Further COLIBRÍ optical upper limit
  55. GRB 250814A: detection of the afterglow candidate with Liverpool Telescope
  56. GRB 250814A: GRAWITA TNG NIR observations
  57. GRB 250814A: Mondy optical observations of the candidate counterpart to LVK S250814bg
  58. GRB250814A: TRT optical upper limits
  59. GRB 250814B: SVOM/GRM observation
  60. GRB 250813B: SVOM/GRM observation
  61. GRB 250814A: P200/WIRC observations of the afterglow candidate
  62. GRB 250814A: possible optical afterglow candidate at Spanish observatories
  63. GRB 250814A: KAIT optical upper limit
  64. GRB 240814A: Fermi GBM Observation
  65. GRB 250814A: Possible afterglow candidate from P200/WIRC
  66. GRB 250813B: Fermi GBM Observation
  67. GRB 250814A: Optical observations with MDM Hiltner 2.4m telescope
  68. Fermi trigger No 776818276: Global MASTER-Net observations report
  69. GRB 250814A: J-band upper limit from WINTER
  70. GRB 250814A: COLIBRÍ optical upper limit
  71. GRB 250814B: Fermi GBM Final Real-time Localization
  72. GRB 250813A: AstroSat CZTI detection
  73. LIGO/Virgo/KAGRA S250814bg: Identification of a GW compact binary merger candidate possibly associated with GRB 250814A detected by Fermi GBM and Swift BAT
  74. Fermi-LAT Gamma-ray Observations of IceCube-250813A
  75. GRB 250814A: Fermi GBM Final Real-time Localization
  76. GRB 250813A: Fermi GBM Final Localization
  77. IceCube-250813A - IceCube observation of a high-energy neutrino candidate track-like event
  78. Fermi Gamma-ray Burst Monitor trigger 776705265/250812644 is not a GRB
  79. Fermi Gamma-ray Burst Monitor trigger 776620220/250811660 is not a GRB
  80. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  81. GRB 250702B: Chandra X-ray Detection
  82. Fermi GRB 250808A: Global MASTER-Net observations report
  83. Fermi Gamma-ray Burst Monitor trigger 776449964/250809689 is not a GRB
  84. GRB 250808A: Fermi GBM Observation
  85. GRB 250808A: SVOM detection of a long burst
  86. GRB 250808A: Fermi GBM Final Real-time Localization
  87. EP250806a: Upper limit from Fermi-GBM Observations
  88. GRB 250804C: AstroSat CZTI detection of a long burst
  89. IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
  90. Fermi trigger No 776041355: Global MASTER-Net observations report
  91. GRB 250804A: Fermi GBM Final Localization
  92. Fermi Gamma-ray Burst Monitor trigger 775945985/250803856 is not a GRB
  93. GRB 250725A: AstroSat CZTI detection
  94. GRB 250725A: PRIME near-infrared observations
  95. GRB 250728A: Swift-XRT observations
  96. GRB 250728A: COLIBRÍ optical upper limit
  97. GRB 250728A: Fermi GBM Observation
  98. Fermi trigger No 775387550: Global MASTER-Net observations report
  99. GRB 250728A: Swift ToO observations
  100. GRB 250728A: Swift/BAT-GUANO arcminute localization of a short burst

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