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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"

27026 results found.

  1. Fermi GRB 260219A: Global MASTER-Net observations report
  2. GRB 260219A: Fermi GBM Final Real-time Localization
  3. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  4. IceCube Alert 260217A: Global MASTER-Net observations report
  5. GRB 260217A: Fermi GBM Final Localization
  6. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  7. sb26021801: SVOM detection of a long faint X-ray transient
  8. The EP-WXT trigger 01709258455 is likely a flaring star
  9. EP-WXT 01709258455: NOT optical upper limits
  10. EP260214b: 1.3m DFOT optical upper limit
  11. IPN triangulation of GRB 260212A
  12. GRB 260213A: GECAM-B observation of a short burst
  13. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  14. GRB 260216A: Fermi GBM Final Real-time Localization
  15. EP260214b: Liverpool Telescope optical observations
  16. EP260214b: Optical upper limit with Kinder observations
  17. EP260214a: Optical upper limits with Kinder observations
  18. EP260214b: EP-FXT follow-up observation
  19. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  20. EP260214b: DDOTI Optical Detection
  21. EP260214b: GROWTH-India Telescope optical upper limit
  22. EP260214a: VLT near-infrared observation
  23. EP260214b: SVOM/VT optical observation
  24. EP260214a: NOT optical upper limits
  25. EP260214a: COLIBRÍ optical upper limits
  26. EP260214b: OHP/T120 optical observations
  27. EP260214a: refined analysis of the EP-FXT observation
  28. EP260214b: LCO optical counterpart detection
  29. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  30. GRB 260211A: SVOM/VT optical counterpart
  31. EP260214b: COLIBRÍ optical observations
  32. EP260214a: SVOM/VT optical upper limits
  33. EP260214b: NOT optical counterpart detection
  34. EP260214b: Einstein Probe detection of a fast X-ray transient
  35. EP260214a: Global MASTER-Net observations report
  36. EP260214a: Einstein Probe detection of an X-ray transient
  37. GRB 260212A: Fermi GBM Observation
  38. EP260213a: Global MASTER-Net observations report
  39. EP260213a: COLIBRÍ optical upper limits
  40. GRB 260212A: GECAM-B observation
  41. EP260213a: Optical upper limits with Kinder observations
  42. EP260213a: SVOM/VT optical upper limit
  43. EP260213a: NUTTelA-TAO Early Optical Limits
  44. EP260213a: SVOM/C-GFT upper limit
  45. EP260213a: refined analysis of the EP-FXT observation
  46. EP260213a: Einstein Probe detection of a fast X-ray transient
  47. EP/WXT 01709258378: NOT optical upper limits
  48. GRB 260212A: SVOM/GRM observation of a long burst
  49. GRB 260213B: Fermi GBM Final Localization
  50. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  51. GRB 260211A - SVOM/ECLAIRs refined analysis
  52. GRB 260204A: SVOM/ECLAIRs refined analysis
  53. GRB 260213A: Fermi GBM Final Localization
  54. GRB 260211A: EP-FXT follow-up observation
  55. GRB 260211A: SVOM/VT optical observation
  56. GRB 260211A: GOTO optical upper limit
  57. Fermi GRB 260212A: Global MASTER-Net observations report
  58. GRB 260212A: Fermi GBM Final Real-time Localization
  59. GRB 260210A: SVOM/GRM observation
  60. Fermi GBM Sub-Threshold Detection of GRB 260211A
  61. GRB 260128B: SVOM/ECLAIRs refined analysis
  62. GRID detection of GRB 260207B
  63. GRB 260211A: LCO optical upper limits
  64. GRB260131A/B: 3.6m DOT Optical Observations
  65. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  66. Fermi trigger No 792537871: Global MASTER-Net observations report
  67. GRB 260211A: SVOM detection of a burst
  68. GRB 260208A: Swift UVOT detection
  69. EP260209a: COLIBRÍ optical upper limit
  70. Fermi GRB 260210C: Global MASTER-Net observations report
  71. EP260209a: LCO optical upper limits
  72. EP260210a: Global MASTER-Net observations report
  73. EP260210a: refined analysis of the EP-FXT observation
  74. EP260209a: Global MASTER-Net observations report
  75. GRB 260208A: LCO detection of the optical counterpart
  76. EP260209a: Einstein Probe detection of a fast X-ray transient
  77. EP260210a: Optical upper limits with Kinder observations
  78. IPN triangulation of GRB 260207B (short/hard with EE)
  79. GRB 260210C: Fermi GBM Final Real-time Localization
  80. GRB 260210B: Fermi GBM Final Real-time Localization
  81. EP260210a: SVOM/VT optical upper limit
  82. EP260210a: COLIBRÍ optical upper limit
  83. EP260210a: SVOM/C-GFT upper limit
  84. GRB 260208B: refined analysis of the EP-FXT observation
  85. EP260210a: Einstein Probe detection of an X-ray transient
  86. GRB 260208C: SVOM/GRM observation
  87. GRB260208A: Liverpool Telescope optical follow-up observations
  88. GRB 260208A: Fermi GBM Observation
  89. Fermi GRB 260209A: Global MASTER-Net observations report
  90. GRB 260208B: Swift-XRT observations
  91. GRB 260204A: Swift/UVOT Upper Limits
  92. GRB 260208B: COLIBRÍ optical observations
  93. GRB 260208A: 1.3m DFOT optical detection
  94. GRB 260208A: COLIBRÍ optical observations
  95. GRB 260208B: EP-FXT observation
  96. GRB 260208A: Liverpool Telescope optical detection
  97. Fermi GRB 260208C: Global MASTER-Net observations report
  98. GRB 260208B: SVOM/VT optical candidate
  99. GRB 260208A: GECAM-B observation of a bright burst
  100. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)

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