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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.

Advanced Search Examples (click to copy):

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

11115 results found.

  1. GRB 241030A: Fermi GBM Final Real-time Localization
  2. GRB 241029A: SAO RAS optical observations
  3. GRB 241026A: SAO RAS optical observations
  4. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  5. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  6. GRB 241026A: Swift/UVOT Upper Limits
  7. GRB 241029A: Fermi GBM Observation
  8. GRB 241029A: AKO Optical Afterglow Detection
  9. GRB 241029A: GOTO optical afterglow detection
  10. GRB 241029A: MASTER early optical counterpart detection
  11. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  12. GRB 241029A: Mephisto observations
  13. GRB 241029A: TRT optical afterglow candidate detection
  14. GRB 241029A: SVOM/GRM observation
  15. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  16. Fermi trigger No 751861204: Global MASTER-Net observations report
  17. GRB 241029A: Fermi GBM Final Real-time Localization
  18. GRB 241026A: the 100th GRB detected by GRBAlpha
  19. GRB 241026A: TNOT optical counterpart detection
  20. Konus-Wind detection of GRB 241025A
  21. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  22. GRB 241026A: LBT redshift confirmation
  23. GRB 241026A: GECAM detection
  24. GRB 241025A: further SAO RAS optical observations
  25. GRB 241026A: BTA and Zeiss-1000 optical observations
  26. GRB 241026A: SVOM/GRM observation
  27. GRB 241026A: GROWTH-India Telescope optical observations
  28. GRB 241026A Fermi GBM Analysis
  29. GRB 241026A: BTA redshift identification of z = 2.79
  30. GRB 241026A: J-band observations with WINTER
  31. GRB 241026A: Las Cumbres optical detection
  32. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  33. GRB 241026A: Swift-XRT refined Analysis
  34. GRB 241026A: Enhanced Swift-XRT position
  35. GRB 241026A: KAIT optical observations
  36. Fermi trigger No 751616906: Global MASTER-Net observations report
  37. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  38. GRB 241026A: SAO RAS observations of possible optical afterglow
  39. Fermi GRB 241026A: Global MASTER-Net observations report
  40. GRB 241026A: Prompt enhanced Swift-XRT position
  41. GRB 241026A: Swift detection of a burst
  42. GRB 241026A: Fermi GBM Final Real-time Localization
  43. ​GRB 241025A: optical photometry from Konkoly
  44. GRB 241025A: GROWTH-India Telescope optical observations
  45. GRB 241025A: COLIBRÍ Detection of the Afterglow
  46. GRB 241025C: Fermi GBM Detection
  47. GRB 241025A: Fermi GBM Observation
  48. GRB 241025C: Fermi GBM Final Localization
  49. GRB 241025B: Fermi GBM Final Localization
  50. Fermi trigger No 751563375: Global MASTER-Net observations report
  51. Fermi trigger No 751554401: Global MASTER-Net observations report
  52. Fermi GRB 241025A: Global MASTER-Net observations report
  53. EP241025a (GRB 241025A): EP observations update
  54. GRB 241025A : SVOM/VT optical afterglow observations
  55. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  56. GRB 241025A: DDOTI Afterglow detection
  57. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  58. GRB 241025A: SVOM/GRM observation
  59. GRB 241025A: TRT optical afterglow observation
  60. Fermi GRB 241024B: Global MASTER-Net observations report
  61. GRB 241025A: Fermi GBM Final Real-time Localization
  62. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  63. GRB 241024B: Fermi GBM Final Localization
  64. EP241021a: No Detection in Fermi-GBM Observation
  65. GRB 241024A: Fermi GBM Final Localisation
  66. Fermi trigger No 751449953: Global MASTER-Net observations report
  67. GRB 241018A: REM optical/NIR upper limits
  68. GRB 241016B: Fermi GBM Observations
  69. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  70. Fermi trigger No 750788395: Global MASTER-Net observations report
  71. GRB 241016B: SVOM/GRM observation
  72. GRB241016C: Fermi GBM Final Localization
  73. Fermi Gamma-ray Burst Monitor trigger 750792698/241016730 is not a GRB
  74. Fermi GRB 241016B: Global MASTER-Net observations report
  75. GRB 241016B: Fermi GBM Final Localization
  76. Fermi GRB 241016A: Global MASTER-Net observations report
  77. GRB 241016A: Fermi GBM Final Real-time Localization
  78. GRB 241013B: Fermi GBM Observation
  79. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  80. GRB 241013A: Fermi GBM Observation
  81. GRB 240916A: radio detection with the VLA
  82. GRB241013A: REM observations
  83. GRB 241013B: SVOM/GRM observation
  84. Fermi GRB 241013B: Global MASTER-Net observations report
  85. GRB 241013B: Fermi GBM Final Real-time Localization
  86. GRB 241013A: a long GRB detected by INTEGRAL
  87. GRB 241013A: Fermi GBM Final Real-time Localization
  88. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  89. GRB 241011A: Fermi GBM Final Real-time Localization
  90. Fermi trigger No 750211959: Global MASTER-Net observations report
  91. Fermi Gamma-ray Burst Monitor trigger 750303285/241011066 is not a GRB
  92. Fermi Gamma-ray Burst Monitor trigger 750291012/241010924 is not a GRB
  93. Fermi trigger No 750291012: Global MASTER-Net observations report
  94. Fermi GRB 241010B: Global MASTER-Net observations report
  95. GRB 241010B: Fermi GBM Final Real-time Localization
  96. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  97. GRB 241008A: Fermi GBM Observation
  98. GRB 241008A: Fermi-LAT detection
  99. GRB 241002B: Swift-XRT afterglow detection
  100. Fermi GRB 241008A: Global MASTER-Net observations report

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