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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"

28857 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. SVOM GRB260917.16: Global MASTER-Net observations report
  12. GRB 260917B: LCO optical observation
  13. GRB 260917B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  14. GRB 260917B: SVOM detection of a faint burst
  15. GRB 260914A: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  16. GRB 260917A: BALROG localization (Fermi Trigger 811304653 / GRB 260917100)
  17. GRB 260917A: Fermi GBM Final Real-time Localization
  18. Fermi trigger No 811304653: Global MASTER-Net observations report
  19. The EP-WXT trigger 01709317235 is likely a flaring star
  20. GRB 260915A: J-band upper limit with WINTER
  21. Fermi trigger No 811264269: Global MASTER-Net observations report
  22. IceCube-260916A - IceCube observation of a high-energy neutrino candidate track-like event
  23. GRB 260914A: SVOM/GRM observation
  24. GRB 260914A: Mondy and TShAO optical observations
  25. GRB 260914A: SVOM/ECLAIRs refined analysis
  26. MAXI GRB260916.37: Global MASTER-Net observations report
  27. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  28. GRB 260915A: SVOM/C-GFT optical upper limits
  29. GRB 260915A: EP-FXT follow-up observation
  30. GRB 260915A: REM optical/NIR observations
  31. GRB 260914A: REM optical/NIR observations
  32. GRB 260914A: VLT/X-shooter observations and redshift confirmation
  33. GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  34. GRB 260914A: VLT/X-shooter spectroscopic redshift z = 0.778
  35. GRB 260915A: 10.4m GTC deep optical limits
  36. GRB 260915A: NOT optical upper limit
  37. SVOM GRB260915.05: Global MASTER-Net observations report
  38. GRB 260915A: SVOM/VT optical upper limits from VHF data
  39. Fermi GBM Sub-Threshold Detection of GRB 260915A
  40. GRB 260915A: LCO optical upper limits
  41. EP Alert 260914.53: Global MASTER-Net observations report
  42. GRB 260914A: EP-FXT follow-up observation
  43. GRB 260915A: SVOM detection of a burst
  44. Fermi GBM Sub-Threshold Detection of GRB 260914A
  45. GRB 260914A: LCO optical observation
  46. GRB 260914A: SVOM/C-GFT optical observations
  47. GRB 260914A: SVOM/VT optical counterpart confirmation
  48. GRB 260914A: SVOM/VT optical observation from VHF data
  49. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  50. SVOM GRB260914.47: Global MASTER-Net observations report
  51. GRB 260914A: SVOM detection of a burst
  52. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  53. GRB 260818A: Continued ATCA observations
  54. SVOM GRB260913.32: Global MASTER-Net observations report
  55. GRB 260913A: SVOM/C-GFT optical upper limit
  56. GRB 260913A: SVOM detection of a faint burst
  57. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  58. GRB 260907A: SVOM/GRM observation
  59. GRB 260909A: CrAO and AbAO optical upper limits
  60. GRB 260909A: SVOM/ECLAIRs refined analysis
  61. GRB 260910B: GOTO tentative optical counterpart candidates
  62. GRB 260910B: Fermi GBM Final Real-time Localization
  63. EP Alert 260909.53: Global MASTER-Net observations report
  64. GRB 260909A: EP-FXT follow-up observation
  65. GRB 260910A: Fermi GBM Final Real-time Localization
  66. GRB 260909A: SVOM/GRM observation
  67. GRB 260909A: Mondy optical observations and afterglow candidate
  68. GRB 260909A: Xinglong 2.16m optical upper limit
  69. GRB 260909A: SVOM/C-GFT optical upper limit
  70. GRB 260909A: SVOM detection of a burst
  71. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  72. Fermi trigger No 810554827: Global MASTER-Net observations report
  73. EP Alert 260908.60: Global MASTER-Net observations report
  74. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  75. Fermi GRB 260907B: Global MASTER-Net observations report
  76. The EP-WXT trigger 01709305715 is likely a flaring star
  77. GRB 260907B: Fermi GBM Final Real-time Localization
  78. Fermi GRB 260907A: Global MASTER-Net observations report
  79. GRB 260907A: Fermi GBM Final Real-time Localization
  80. EP Alert 260905.11: Global MASTER-Net observations report
  81. The EP-WXT trigger 01709302592 is likely a flaring star
  82. GRB 260903A: J-band upper limit with WINTER
  83. EP Alert 260903.47: Global MASTER-Net observations report
  84. GRB 260903A: SVOM/ECLAIRs refined analysis
  85. GRB260903A: Liverpool Telescope optical observations
  86. EP Alert 260903.62: Global MASTER-Net observations report
  87. GRB 260903A: EP-FXT follow-up observation
  88. GRB 260903A: NOT optical observations and afterglow fading
  89. SVOM GRB260903A: Global MASTER-Net observations report
  90. GRB 260903A: LCO optical observations
  91. GRB 260903A: SVOM/VT optical candidate
  92. GRB 260831A: GECAM-B observation
  93. GRB 260903A: LCO optical counterpart detection
  94. GRB 260827A: Insight-HXMT/HE detection
  95. GRB 260903A: SVOM detection of a soft faint burst
  96. EP260901a: SVOM/VT optical upper limits
  97. Konus-Wind detection of GRB 260829A
  98. GRB 260829A: SVOM/GRM observation
  99. GRB 260818A: ATCA detection of a candidate radio counterpart
  100. EP260901a: Global MASTER-Net observations report

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