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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"

43681 results found.

  1. GRB 260601B / EP260601a: AstroSat CZTI detection
  2. GRB 260527A/EP260527a: 6 GHz VLA observations
  3. GRB 260604C: GOTO detections of the optical afterglow
  4. GRB 260604C: Correction to GCN 44828
  5. GRB 260604C: Kilonova-Catcher optical afterglow detection
  6. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
  7. The EP-WXT trigger 01709266798 is likely a flaring star
  8. GRB 260604C: Jinshan optical observations
  9. GRB 260604C: Fermi GBM Observation
  10. EP260602d: J-band upper limit with WINTER
  11. EP260602b: J-band upper limit with WINTER
  12. GRB 260604C: LAST detection of optical counterpart candidate
  13. Fermi GRB 260604C: Global MASTER-Net observations report
  14. Fermi GRB 260604C: Global MASTER-Net observations report
  15. SVOM GRB260604.85: Global MASTER-Net observations report
  16. GRB 260604C: SVOM detection of a long burst
  17. GRB 260604C: Fermi GBM Final Real-time Localization
  18. GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
  19. GRB 260603A: NOT optical observations
  20. GRB 260603A: Simeiz Zeiss-1000 optical upper limit
  21. GRB 260604B: Fermi GBM Final Real-time Localization
  22. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  23. EP260602a: EP-FXT follow-up observation
  24. EP260603a: Global MASTER-Net observations report
  25. EP260603a: Einstein Probe detection of a fast X-ray transient
  26. EP260602d: Optical Upper limits with kinder observations
  27. GRB 260604A: Fermi GBM Final Real-time Localization
  28. EP260602b: Liverpool Telescope observations
  29. EP260602a: Liverpool Telescope optical upper limits
  30. EP260602b: Liverpool Telescope and LCO observations
  31. GRB 260603B: Fermi GBM Final Localization
  32. EP260602a: GTC and Liverpool Telescope optical observations
  33. Konus-Wind detection of GRB 260601B/EP260601a
  34. GRB 260603A: EP-FXT follow-up observation
  35. EP260601a/GRB 260601B: EP-FXT follow-up observation
  36. GRB 260601B / EP260601a: Mondy optical upper limit
  37. EP260602b: EP-FXT follow-up observation
  38. GRB 260601B/EP260601a: Glowbug gamma-ray detection
  39. GRB 260603A: Kilonova-Catcher optical upper limit
  40. GRB 260603A: SVOM/VT optical observations
  41. EP260602a: NOT NIR J-band observations
  42. GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
  43. EP260602d: Einstein Probe detection of a fast X-ray transient
  44. Fermi trigger No 802141998: Global MASTER-Net observations report
  45. EP260602a: SVOM/VT optical magnitudes correction
  46. GRB 260601A: SVOM/GRM observation of a short burst
  47. EP260602c: Einstein Probe detection of a fast X-ray transient
  48. GRB 260603A: SVOM/COLIBRÍ (GFT-FM) optical counterpart candidate
  49. EP260602a: COLIBRÍ optical observations
  50. GRB260601B/EP260601a: NOT near-infrared observations
  51. SVOM GRB260603.23: Global MASTER-Net observations report
  52. GRB 260603A: SVOM detection of a burst
  53. EP260602b: Einstein Probe detection of a fast X-ray transient
  54. GRB 260601B/EP260601a: Insight-HXMT detection
  55. Fermi GRB 260602B: Global MASTER-Net observations report
  56. Fermi GRB 260602B: Global MASTER-Net observations report
  57. EP260530a: Xinglong optical spectroscopy of EP260530a / AT 2026nwl
  58. EP260602a: SVOM/VT optical candidate
  59. EP-WXT trigger 01709266414 (EP260602b): JinShan optical counterpart detection
  60. GRB 260602B: Fermi GBM Final Localization
  61. GRB 260601A: GECAM-B observation of a short burst
  62. GRB 260601B/EP260601a: J-band upper limit with WINTER
  63. EP260530a/AT 2026nwl: COLIBRÍ optical follow up
  64. EP260530a/AT 2026nwl: KAIT optical observations
  65. GRB 260602A: Fermi GBM Final Real-time Localization
  66. GRB 260601B: CALET Gamma-Ray Burst Monitor detection
  67. EP260602a: Optical upper limits with Kinder observations
  68. GRB 260601B / EP260601a: NuSTAR detection of prompt emission
  69. EP260602a: Einstein Probe detection of a fast X-ray transient
  70. GRB 260601B/EP260601a: SVOM/VT optical observations
  71. GRB 260601B/EP260601a: GECAM-B analysis suggests a possible long duration Type I burst
  72. GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
  73. EP260601a: Einstein Probe detection of an X-ray transient
  74. EP-WXT trigger 01709266307 (EP260601a): COLIBRÍ optical observations
  75. EP-WXT trigger 01709266307 (EP260601a): JinShan optical counterpart detection
  76. GRB 260601A: Glowbug gamma-ray detection of a short burst
  77. GRB 260531B: Glowbug gamma-ray detection
  78. GRB 260516D: VLA radio detection
  79. GRB 260601A: Fermi GBM Observation
  80. EP260530a/AT 2026nwl: COLIBRÍ optical observations
  81. GRB 260530C: SVOM/ECLAIRs detection of a burst through on-ground search
  82. GRB 260527A/EP260527a: Glowbug gamma-ray detection
  83. Fermi GRB 260601A: Global MASTER-Net observations report
  84. GRB 260601A: Fermi GBM Final Real-time Localization
  85. GRB 260531B: GECAM-B observation
  86. GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
  87. The EP-WXT trigger 01709266272 is likely a flaring star
  88. GRB 260531C: Fermi GBM Final Localization Correction
  89. Fermi Gamma-ray Burst Monitor trigger 801900520/260531256 is not a GRB
  90. AT2026nik: EP-FXT X-ray counterpart
  91. Fermi trigger No 801900520: Global MASTER-Net observations report
  92. GRB 260531B: Fermi GBM Final Real-time Localization
  93. GRB 260531A: MAXI/GSC detection
  94. AT 2026nuz: COLIBRÍ optical observations
  95. IPN triangulation of GRB 260527A / EP260527a
  96. EP260527a/GRB 260527A: further FTW optical and NIR observations
  97. GRB 260530B: SVOM/GRM detection of a possible bright short GRB
  98. GRB 260530A: Fermi GBM Final Real-time Localization
  99. GRB 260527A / EP260527a: VLA radio detection
  100. EP260527a/GRB 260527A: optical upper limit with Kinder observations

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