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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"

37940 results found.

  1. GRB 260918A: LCO optical upper limits
  2. GRB 260918A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  3. GRB 260918A: SVOM detection of a burst
  4. GRB 260917C: Fermi GBM Final Real-time Localization
  5. GRB 260917B: FRAM-Auger optical limits
  6. GRB 260916B: Fermi GBM Detection
  7. GRB 260916B: Fermi GBM Final Localization
  8. GRB 260917A: Glowbug gamma-ray detection
  9. GRB 260915A: SVOM/ECLAIRs refined analysis
  10. GRB 260917B: WINTER J-band observations
  11. GRB 260917B: SVOM/VT optical observations
  12. SVOM GRB260917.16: Global MASTER-Net observations report
  13. GRB 260917B: LCO optical observation
  14. GRB 260917B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  15. GRB 260917B: SVOM detection of a faint burst
  16. GRB 260914A: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  17. GRB 260917A: BALROG localization (Fermi Trigger 811304653 / GRB 260917100)
  18. GRB 260917A: Fermi GBM Final Real-time Localization
  19. Fermi trigger No 811304653: Global MASTER-Net observations report
  20. GRB 260915A: J-band upper limit with WINTER
  21. Fermi trigger No 811264269: Global MASTER-Net observations report
  22. GRB 260909A: NOEMA detection
  23. GRB 260914A: SVOM/GRM observation
  24. GRB 260914A: Mondy and TShAO optical observations
  25. GRB 260914A: SVOM/ECLAIRs refined analysis
  26. GRB 260909A: Swift-XRT observations
  27. GRB 260916A: MAXI/GSC detection
  28. MAXI GRB260916.37: Global MASTER-Net observations report
  29. GRB 260915A: Swift ToO observations
  30. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  31. GRB 260915A: SVOM/C-GFT optical upper limits
  32. GRB 260915A: EP-FXT follow-up observation
  33. GRB 260915A: SVOM/VT refined early optical upper limits
  34. GRB 260915A: EP-FXT follow-up observation
  35. GRB 260915A: REM optical/NIR observations
  36. GRB 260914A: REM optical/NIR observations
  37. GRB 260914A: VLT/X-shooter observations and redshift confirmation
  38. GRB 260915A: SVOM/VT optical upper limits
  39. GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  40. GRB 260914A: VLT/X-shooter spectroscopic redshift z = 0.778
  41. GRB 260915A: 10.4m GTC deep optical limits
  42. GRB 260915A: NOT optical upper limit
  43. SVOM GRB260915.05: Global MASTER-Net observations report
  44. GRB 260915A: SVOM/VT optical upper limits from VHF data
  45. Fermi GBM Sub-Threshold Detection of GRB 260915A
  46. GRB 260915A: LCO optical upper limits
  47. EP Alert 260914.53: Global MASTER-Net observations report
  48. GRB 260914A: EP-FXT follow-up observation
  49. GRB 260915A: SVOM detection of a burst
  50. Fermi GBM Sub-Threshold Detection of GRB 260914A
  51. GRB 260914A: LCO optical observation
  52. GRB 260914A: SVOM/C-GFT optical observations
  53. GRB 260914A: SVOM/VT optical counterpart confirmation
  54. GRB 260914A: SVOM/VT optical observation from VHF data
  55. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  56. SVOM GRB260914.47: Global MASTER-Net observations report
  57. GRB 260914A: SVOM detection of a burst
  58. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  59. GRB 260818A: Continued ATCA observations
  60. SVOM GRB260913.32: Global MASTER-Net observations report
  61. GRB 260913A: SVOM/C-GFT optical upper limit
  62. GRB 260913A: SVOM detection of a faint burst
  63. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  64. GRB 260907A: SVOM/GRM observation
  65. GRB 260909A: CrAO and AbAO optical upper limits
  66. GRB 260909A: SVOM/ECLAIRs refined analysis
  67. GRB 260910B: GOTO tentative optical counterpart candidates
  68. GRB 260909A: Swift ToO observations
  69. GRB 260910B: Fermi GBM Final Real-time Localization
  70. GRB 260909A: KAIT optical upper limit
  71. GRB 260903A: Swift-XRT observations
  72. GRB 260909A: OHP/T193 z-band upper limit
  73. GRB 260909A: VLT optical and near-infrared upper limits
  74. EP Alert 260909.53: Global MASTER-Net observations report
  75. GRB 260909A: EP-FXT follow-up observation
  76. GRB 260910A: Fermi GBM Final Real-time Localization
  77. GRB 260909A: SVOM/VT optical upper limits
  78. GRB 260909A: SVOM/GRM observation
  79. GRB 260909A: Mondy optical observations and afterglow candidate
  80. GRB 260909A: Xinglong 2.16m optical upper limit
  81. GRB 260909A: SVOM/C-GFT optical upper limit
  82. GRB 260909A: SVOM detection of a burst
  83. Fermi trigger No 810554827: Global MASTER-Net observations report
  84. EP Alert 260908.60: Global MASTER-Net observations report
  85. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  86. GRB 260903A: Swift ToO observations
  87. Fermi GRB 260907B: Global MASTER-Net observations report
  88. GRB 260903A: SAO RAS optical upper limit
  89. GRB 260907B: Fermi GBM Final Real-time Localization
  90. Fermi GRB 260907A: Global MASTER-Net observations report
  91. GRB 260907A: Fermi GBM Final Real-time Localization
  92. EP Alert 260905.11: Global MASTER-Net observations report
  93. GRB 260903A: J-band upper limit with WINTER
  94. EP Alert 260903.47: Global MASTER-Net observations report
  95. GRB 260903A: SVOM/ECLAIRs refined analysis
  96. GRB260903A: Liverpool Telescope optical observations
  97. GRB 260903A: SAO RAS optical observations
  98. GRB 260830A: GECAM-B detection of a burst
  99. EP Alert 260903.62: Global MASTER-Net observations report
  100. GRB 260830A: Insight-HXMT/HE detection

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