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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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.

Lucene Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

3363 results found.

  1. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  2. Fermi GRB 250128B: Global MASTER-Net observations report
  3. Fermi GRB 250127B: Global MASTER-Net observations report
  4. IPN triangulation of GRB 250119C
  5. GRB 250126A: CALET Gamma-Ray Burst Monitor detection
  6. GRB 250126A: MAXI/GSC detection
  7. GRB 250114A: Swift-BAT refined analysis
  8. GRB 250101A: Terskol Zeiss-2000 optical observations
  9. EP250111a: Mondy optical observation
  10. EP250111a: Global MASTER-Net observations report
  11. GRB 250108B: 1.3m DFOT upper limit
  12. EP250109a: Global MASTER-Net observations report
  13. EP250108a: Global MASTER-Net observations report
  14. Fermi GRB 250107B: Global MASTER-Net observations report
  15. Fermi trigger No 757753930: Global MASTER-Net observations report
  16. GRB 250103A: Fermi GBM Observation
  17. GRB 250103A: SVOM/C-GFT optical upper limit
  18. GRB 250101A NUTTelA-TAO / BSTI Early Measurements
  19. GRB 250101A: OASDG optical observations
  20. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  21. GRB 241228B: SAO RAS optical observations
  22. Konus-Wind detection of GRB 241228A
  23. GRB 241229B: Swift-BAT refined analysis
  24. Fermi GRB 241228B: Global MASTER-Net observations report
  25. GRB 241228A: Fermi GBM Observation
  26. GRB 241228B: TRT optical counterpart confirmation
  27. GRB 241228A: Swift detection of a burst
  28. Fermi trigger No 756678579: Global MASTER-Net observations report
  29. GRB 241217A/EP241217b: SOAR afterglow detection
  30. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  31. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  32. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  33. EP241217a: Liverpool Telescope optical follow-up
  34. EP241217a: Global MASTER-Net observations report
  35. GRB 241217A: GMG Optical Upper Limit
  36. GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
  37. GRB 241213B: Swift-XRT observations
  38. GRB 241213B: Tiled Swift observations
  39. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  40. GRB 241213B: MAXI/GSC detection
  41. EP241208a: Global MASTER-Net observations report
  42. Fermi GRB 241209E: Global MASTER-Net observations report
  43. Fermi GRB 241209A: Global MASTER-Net observations report
  44. GRB 241207C: MASTER optical observations
  45. GRB 241207C: Tiled Swift observations
  46. GRB 241207C: MAXI/GSC detection
  47. Fermi GRB 241206A: Global MASTER-Net observations report
  48. Fermi GRB 241204A: Global MASTER-Net observations report
  49. Fermi GRB 241201A: Global MASTER-Net observations report
  50. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  51. GRB 241127A: Swift-BAT refined analysis
  52. GRB 241026A: radio detection with the VLA
  53. GRB241120A: OHP/T193 optical observations
  54. GRB 241120A: Mondy and AbAO optical observations
  55. Fermi GRB 241118A: Global MASTER-Net observations report
  56. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  57. EP241113a: Global MASTER-Net observations report
  58. Fermi trigger No 753166198: Global MASTER-Net observations report
  59. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  60. GRB 241112B: SVOM/GRM observation
  61. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  62. Fermi trigger No 752990530: Global MASTER-Net observations report
  63. Fermi trigger No 752878030: Global MASTER-Net observations report
  64. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  65. EP241107a: AKO Optical Afterglow Follow-Up Observations
  66. GRB 240511A: LCO upper limits
  67. Fermi GRB 241105A: Global MASTER-Net observations report
  68. Fermi GRB 241104A: Global MASTER-Net observations report
  69. EP241101a: EP-FXT observations update
  70. Fermi trigger No 752365806: Global MASTER-Net observations report
  71. EP241103a: Swift XRT detection and improved X-ray position
  72. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  73. GRB 241101A: Swift detection of a burst
  74. Fermi trigger No 752083996: Global MASTER-Net observations report
  75. EP EP241030a: Global MASTER-Net observations report
  76. Fermi trigger No 752006065: Global MASTER-Net observations report
  77. GRB 241030B: Swift detection of a burst
  78. GRB 240912A: radio detection with the VLA
  79. Fermi GRB 241030A: Global MASTER-Net observations report
  80. GRB 241026A: SAO RAS observations of possible optical afterglow
  81. Fermi GRB 241026A: Global MASTER-Net observations report
  82. GRB 241026A: Prompt enhanced Swift-XRT position
  83. EP241021a: optical follow-up observations with Xinglong Observatory
  84. Fermi GRB 241025A: Global MASTER-Net observations report
  85. IPN triangulation of GRB 241021A (long)
  86. GRB241017A: 1.3m DFOT optical upper limit
  87. Fermi trigger No 750788395: Global MASTER-Net observations report
  88. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  89. Fermi GRB 241016A: Global MASTER-Net observations report
  90. GRB 240916A: radio detection with the VLA
  91. GRB241013A: REM observations
  92. Fermi trigger No 750211959: Global MASTER-Net observations report
  93. IceCube Alert 241006.94: Global MASTER-Net observations report
  94. EP EP240930a: Global MASTER-Net observations report
  95. Fermi GRB 240929A: Global MASTER-Net observations report
  96. LIGO/Virgo S240919bn: GOTO optical upper limits
  97. GRB 240918B: AstroSat CZTI detection
  98. EP240919a: EP-FXT follow-up observation update
  99. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  100. GRB 240918B: Fermi GBM Detection

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