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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"

44408 results found.

  1. GRB 260212A: Fermi GBM Observation
  2. EP260213a: Liverpool Telescope optical upper limits
  3. EP260213a: Global MASTER-Net observations report
  4. EP260213a: COLIBRÍ optical upper limits
  5. GRB 260212A: GECAM-B observation
  6. EP260213a: Optical upper limits with Kinder observations
  7. EP260213a: SVOM/VT optical upper limit
  8. EP260213a: Mondy R-band optical upper limit
  9. EP260213a: NUTTelA-TAO Early Optical Limits
  10. EP260213a: SVOM/C-GFT upper limit
  11. EP260213a: refined analysis of the EP-FXT observation
  12. EP260213a: Einstein Probe detection of a fast X-ray transient
  13. EP/WXT 01709258378: NOT optical upper limits
  14. GRB 260212A: SVOM/GRM observation of a long burst
  15. GRB 260213B: Fermi GBM Final Localization
  16. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  17. GRB 260211A - SVOM/ECLAIRs refined analysis
  18. GRB 260204A: SVOM/ECLAIRs refined analysis
  19. GRB 260213A: Fermi GBM Final Localization
  20. GRB 260211A: EP-FXT follow-up observation
  21. GRB 260211A: SVOM/VT optical observation
  22. GRB 260212A: Glowbug gamma-ray detection
  23. GRB 260211A: GOTO optical upper limit
  24. Fermi GRB 260212A: Global MASTER-Net observations report
  25. GRB 260212A: Fermi GBM Final Real-time Localization
  26. GRB 260211A: LAST optical upper limit
  27. GRB 260210A: SVOM/GRM observation
  28. Fermi GBM Sub-Threshold Detection of GRB 260211A
  29. Konus-Wind detection of GRB 260207B
  30. GRB 260128B: SVOM/ECLAIRs refined analysis
  31. GRID detection of GRB 260207B
  32. GRB 260211A: LCO optical upper limits
  33. GRB260131A/B: 3.6m DOT Optical Observations
  34. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  35. Fermi trigger No 792537871: Global MASTER-Net observations report
  36. GRB 260211A: SVOM detection of a burst
  37. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  38. Konus-Wind detection of GRB 260209B
  39. GRB 260208A: Swift UVOT detection
  40. Konus-Wind detection of GRB 260127B
  41. EP260209a: COLIBRÍ optical upper limit
  42. Fermi GRB 260210C: Global MASTER-Net observations report
  43. EP260209a: LCO optical upper limits
  44. EP260210a: Global MASTER-Net observations report
  45. EP260210a: refined analysis of the EP-FXT observation
  46. EP260209a: Global MASTER-Net observations report
  47. GRB 260208A: LCO detection of the optical counterpart
  48. EP260209a: Einstein Probe detection of a fast X-ray transient
  49. EP260210a: Optical upper limits with Kinder observations
  50. IPN triangulation of GRB 260207B (short/hard with EE)
  51. GRB 260210C: Fermi GBM Final Real-time Localization
  52. GRB 260210A: Glowbug gamma-ray detection
  53. GRB 260210B: Fermi GBM Final Real-time Localization
  54. EP260210a: SVOM/VT optical upper limit
  55. GRB 260210A: AstroSat CZTI detection
  56. GRB 260208C: AstroSat CZTI detection
  57. EP260210a: COLIBRÍ optical upper limit
  58. EP260210a: SVOM/C-GFT upper limit
  59. GRB 260208B: refined analysis of the EP-FXT observation
  60. EP260210a: Einstein Probe detection of an X-ray transient
  61. GRB 260207B: AstroSat CZTI detection
  62. GRB 260208C: SVOM/GRM observation
  63. GRB 260204A: Swift-XRT afterglow detection
  64. GRB 260208B: AstroSat CZTI detection of a bright long burst
  65. GRB260208A: Liverpool Telescope optical follow-up observations
  66. GRB 260208A: Glowbug gamma-ray detection
  67. GRB 260208A: NuSTAR detection of prompt emission
  68. GRB 260208A: Fermi GBM Observation
  69. Fermi GRB 260209A: Global MASTER-Net observations report
  70. GRB 260208B: Swift-XRT observations
  71. GRB 260131A/B: continued Mondy optical observations
  72. GRB 260204A: Swift/UVOT Upper Limits
  73. GRB 260208B: COLIBRÍ optical observations
  74. GRB 260208A: Mondy optical observations (duplicate submission)
  75. GRB 260208A: Mondy optical observations
  76. GRB 260208A: 1.3m DFOT optical detection
  77. GRB 260208A: COLIBRÍ optical observations
  78. GRB 260208B: EP-FXT observation
  79. GRB 260208A: NOT spectroscopic redshift z = 2.36
  80. GRB 260208A: Liverpool Telescope optical detection
  81. Fermi GRB 260208C: Global MASTER-Net observations report
  82. GRB 260208B: SVOM/VT optical candidate
  83. GRB 260208A: GECAM-B observation of a bright burst
  84. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  85. GRB 260209A: Fermi GBM Final Real-time Localization
  86. GRB 260208A: SVOM/VT optical observation
  87. Fermi GRB 260208D: Global MASTER-Net observations report
  88. GRB 260208D: Fermi GBM Final Real-time Localization
  89. GRB 260208A: Swift-XRT observations
  90. GRB 260208B: Swift ToO observations
  91. GRB 260208B: SVOM/GRM observation of a bright burst
  92. GRB 260208B: Fermi GBM Detection
  93. LAT GRB 260208B: Global MASTER-Net observations report
  94. GRB 260208B: Fermi-LAT detection
  95. GRB 260208C: Fermi GBM Final Real-time Localization
  96. GRB 260208A: Fermi-LAT detection
  97. GRB 260207B: GECAM-B observation
  98. GRB 260208A: Swift ToO observations
  99. GRB 260208A: Fermi GBM Classification Correction
  100. GRB 260208A: GOTO detection of a potential optical counterpart (GOTO26aob)

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