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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"

37579 results found.

  1. EP-WXT trigger 01709195487: KAIT confirmation of the stellar flare
  2. GRB 250808A: SVOM detection of a long burst
  3. GRB 250808A: Fermi GBM Final Real-time Localization
  4. Konus-Wind detection of GRB 250807A
  5. GRB 250807B: Swift/UVOT Detection
  6. GRB 250807B: Kilonova-Catcher optical afterglow detection
  7. GRB 250807A: Swift/UVOT Detection
  8. GRB 250807A: Swift-XRT refined Analysis
  9. GRB 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
  10. GRB 250806A: SVOM/MXT refined analysis
  11. GRB 250806A: SVOM/ECLAIRs refined analysis
  12. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  13. GRB 250804B: Insight-HXMT detection
  14. GRB 250807A: SVOM/GRM observation
  15. GRB 250807A: AstroSat CZTI detection of bright long burst
  16. GRB 250807B: Swift-XRT refined Analysis
  17. GRB 250806A: NOT z-band upper limit and host galaxy candidate
  18. GRB 250807B: NTT optical observations
  19. GRB 250807A: SVOM/VT optical observation
  20. EP250806a: Upper limit from Fermi-GBM Observations
  21. GRB 250807B: Enhanced Swift-XRT position
  22. GRB 250807A: Enhanced Swift-XRT position
  23. GRB 250807B: Swift detection of a burst with an optical counterpart.
  24. GRB 250805A: Kilonova-Catcher optical upper limits
  25. GRB 250805A: Swift/UVOT Upper Limits
  26. GRB 250806A: Swift/UVOT U-band detection
  27. GRB 250807A: Swift detection of a burst with an optical counterpart
  28. GRB 250806A: EP-FXT observation
  29. GRB 250806A: J-band upper limit from WINTER
  30. GRB 250805A: Swift-BAT refined analysis
  31. GRB 250806A: KAIT optical upper limit
  32. GRB 250806A: SVOM/VT refined analysis
  33. GRB 250806A: Swift-XRT counterpart detection
  34. GRB 250806A: Kilonova-Catcher optical upper limits
  35. GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  36. GRB 250806A: SVOM/VT optical upper limit
  37. GRB 250806A: SVOM detection of a soft burst
  38. GRB 250805A: SVOM/VT optical counterpart
  39. GRB 250805A: ESO/VLT observations
  40. GRB 250805A: Swift-XRT refined Analysis
  41. GRB 250804B: Swift-XRT observations
  42. GRB 250805A: Enhanced Swift-XRT position
  43. GRB 250804C: AstroSat CZTI detection of a long burst
  44. GRB 250805A: TRT optical upper limits
  45. IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
  46. GRB 250805A: Swift-XRT observations
  47. GRB 250805A: Swift detection of a burst
  48. GRB 250804B: Tiled Swift observations
  49. Fermi trigger No 776041355: Global MASTER-Net observations report
  50. GRB 250804B: SVOM/GRM observation of a short burst
  51. GRB 250804A: Fermi GBM Final Localization
  52. Fermi Gamma-ray Burst Monitor trigger 775945985/250803856 is not a GRB
  53. GRB 250702B: SMA observations
  54. EP250711a: CrAO and Assy optical observations
  55. GRB 250727A: Swift-XRT afterglow confirmation and refined analysis
  56. LIGO/Virgo/KAGRA S250726ak: Upper limits from Swift/BAT-GUANO
  57. LIGO/Virgo/KAGRA S250725l: Upper limits from Swift/BAT-GUANO
  58. LIGO/Virgo/KAGRA S250727dc: Upper limits from Swift/BAT-GUANO
  59. GRB 250725A: AstroSat CZTI detection
  60. GRB 250727A: EP-FXT follow-up observation
  61. GRB 250725A: PRIME near-infrared observations
  62. GRB: Clarification on Gamma-Ray Burst Naming Convention
  63. GRB 250728A: Swift-XRT observations
  64. GRB 250727A: SVOM/ECLAIRs refined analysis
  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 250727A: AST3-2 Upper limit
  71. GRB 250727A: EP-FXT counterpart detection
  72. GRB250727A: SVOM/VT optical upper limit
  73. GRB 250727A: Swift-XRT observations
  74. GRB 250727A: SVOM detection of a burst
  75. GRB 250725A: Swift-XRT refined Analysis
  76. GRB 250725A: Fermi GBM Observation
  77. GRB 250725A: Swift-BAT refined analysis
  78. Konus-Wind detection of GRB 250725A
  79. GRB 250725A: SVOM/GRM observation
  80. GRB 250725A: Global MASTER-Net: First Optical Synchronous Observatios of Short GRB.
  81. GRB 250725A: Swift/UVOT Upper Limits
  82. GRB 250725A: Fermi-LAT detection
  83. GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
  84. GRB 250725A: BOOTES-7 early optical detection
  85. GRB 250725A: SVOM/VT optical candidate
  86. GRB 250725A: MASTER-OAFA optical detection of very fast afterglow
  87. GRB 250725A: Enhanced Swift-XRT position
  88. GRB 250725A: Swift detection of a burst
  89. Swift GRB 250725A: Global MASTER-Net OT detection
  90. GRB 250725A: Fermi GBM Final Real-time Localization
  91. Fermi GRB 250725A: Global MASTER-Net observations report
  92. Swift GRB 250725A: Global MASTER-Net observations report
  93. GRB 250723B: Fermi GBM Final Real-time Localization
  94. GRB 250721A: Fermi GBM Observation
  95. GRB 250723A: Fermi GBM Final Real-time Localization
  96. Swift-BAT trigger 1334535 is not a GRB
  97. GRB 250721A: Swift-XRT observations
  98. GRB 250722A: Fermi GBM Final Real-time Localization
  99. GRB 250713A : SVOM/ECLAIRs refined analysis
  100. GRB 250717B: SVOM/GRM observation

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