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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"

27637 results found.

  1. Fermi GRB 260221B: Global MASTER-Net observations report
  2. GRB 260221B: Fermi GBM Final Real-time Localization
  3. EP-WXT01709258519: Xinglong optical upper limit
  4. EP260221a: Xinglong optical upper limit
  5. Fermi GRB 260221A: Global MASTER-Net observations report
  6. GRB 260221A: Fermi GBM Final Real-time Localization
  7. EP260221a: GOTO optical upper limit
  8. EP260221a: COLIBRÍ optical upper limit
  9. SVOM alert sb26021801: LCO optical upper limit
  10. The EP-WXT trigger 01709258519 is likely caused by Mrk 421
  11. Fermi GRB 260219A: Global MASTER-Net observations report
  12. GRB 260219A: Fermi GBM Final Real-time Localization
  13. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  14. IceCube Alert 260217A: Global MASTER-Net observations report
  15. GRB 260217A: Fermi GBM Final Localization
  16. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  17. sb26021801: SVOM detection of a long faint X-ray transient
  18. The EP-WXT trigger 01709258455 is likely a flaring star
  19. EP-WXT 01709258455: NOT optical upper limits
  20. EP260214b: 1.3m DFOT optical upper limit
  21. IPN triangulation of GRB 260212A
  22. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  23. GRB 260216A: Fermi GBM Final Real-time Localization
  24. EP260214b: Liverpool Telescope optical observations
  25. EP260214b: Optical upper limit with Kinder observations
  26. EP260214a: Optical upper limits with Kinder observations
  27. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  28. EP260214b: DDOTI Optical Detection
  29. EP260214b: GROWTH-India Telescope optical upper limit
  30. EP260214a: VLT near-infrared observation
  31. EP260214b: SVOM/VT optical observation
  32. EP260214a: NOT optical upper limits
  33. EP260214a: COLIBRÍ optical upper limits
  34. EP260214b: OHP/T120 optical observations
  35. EP260214b: LCO optical counterpart detection
  36. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  37. GRB 260211A: SVOM/VT optical counterpart
  38. EP260214b: COLIBRÍ optical observations
  39. EP260214a: SVOM/VT optical upper limits
  40. EP260214b: NOT optical counterpart detection
  41. EP260214a: Global MASTER-Net observations report
  42. GRB 260212A: Fermi GBM Observation
  43. EP260213a: Global MASTER-Net observations report
  44. EP260213a: COLIBRÍ optical upper limits
  45. EP260213a: Optical upper limits with Kinder observations
  46. EP260213a: SVOM/VT optical upper limit
  47. EP260213a: NUTTelA-TAO Early Optical Limits
  48. EP260213a: SVOM/C-GFT upper limit
  49. EP/WXT 01709258378: NOT optical upper limits
  50. GRB 260213B: Fermi GBM Final Localization
  51. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  52. GRB 260213A: Fermi GBM Final Localization
  53. GRB 260211A: EP-FXT follow-up observation
  54. GRB 260211A: SVOM/VT optical observation
  55. GRB 260211A: GOTO optical upper limit
  56. Fermi GRB 260212A: Global MASTER-Net observations report
  57. GRB 260212A: Fermi GBM Final Real-time Localization
  58. GRB 260210A: SVOM/GRM observation
  59. Fermi GBM Sub-Threshold Detection of GRB 260211A
  60. GRID detection of GRB 260207B
  61. GRB 260211A: LCO optical upper limits
  62. GRB260131A/B: 3.6m DOT Optical Observations
  63. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  64. Fermi trigger No 792537871: Global MASTER-Net observations report
  65. GRB 260211A: SVOM detection of a burst
  66. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  67. GRB 260208A: Swift UVOT detection
  68. EP260209a: COLIBRÍ optical upper limit
  69. Fermi GRB 260210C: Global MASTER-Net observations report
  70. EP260209a: LCO optical upper limits
  71. EP260210a: Global MASTER-Net observations report
  72. EP260210a: refined analysis of the EP-FXT observation
  73. EP260209a: Global MASTER-Net observations report
  74. GRB 260208A: LCO detection of the optical counterpart
  75. EP260210a: Optical upper limits with Kinder observations
  76. IPN triangulation of GRB 260207B (short/hard with EE)
  77. GRB 260210C: Fermi GBM Final Real-time Localization
  78. GRB 260210B: Fermi GBM Final Real-time Localization
  79. EP260210a: SVOM/VT optical upper limit
  80. EP260210a: COLIBRÍ optical upper limit
  81. EP260210a: SVOM/C-GFT upper limit
  82. GRB 260208B: refined analysis of the EP-FXT observation
  83. GRB260208A: Liverpool Telescope optical follow-up observations
  84. GRB 260208A: Fermi GBM Observation
  85. Fermi GRB 260209A: Global MASTER-Net observations report
  86. GRB 260208B: Swift-XRT observations
  87. GRB 260204A: Swift/UVOT Upper Limits
  88. GRB 260208B: COLIBRÍ optical observations
  89. GRB 260208A: 1.3m DFOT optical detection
  90. GRB 260208A: COLIBRÍ optical observations
  91. GRB 260208B: EP-FXT observation
  92. GRB 260208A: Liverpool Telescope optical detection
  93. Fermi GRB 260208C: Global MASTER-Net observations report
  94. GRB 260208B: SVOM/VT optical candidate
  95. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  96. GRB 260209A: Fermi GBM Final Real-time Localization
  97. GRB 260208A: SVOM/VT optical observation
  98. Fermi GRB 260208D: Global MASTER-Net observations report
  99. GRB 260208D: Fermi GBM Final Real-time Localization
  100. GRB 260208B: SVOM/GRM observation of a bright burst

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