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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"

41622 results found.

  1. EP Alert 260921.01: Global MASTER-Net observations report
  2. EP260920b: Global MASTER-Net observations report
  3. EP260920b: Einstein Probe detection of an X-ray transient
  4. IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
  5. EP Alert 260920.66: Global MASTER-Net observations report
  6. EP-WXT detected a brightening of HMXB LS V +44 17
  7. EP260920a: NOT early time optical upper limits
  8. EP260920a: NOT optical upper limits
  9. GRB 260920A: Fermi GBM Final Real-time Localization
  10. EP260920a: SVOM/VT optical upper limits
  11. EP260917a: Global MASTER-Net observations report
  12. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  13. EP260920a: COLIBRÍ optical upper limits
  14. EP260917b: EP-FXT non-detection and upper limit
  15. IceCube Alert 260919A: Global MASTER-Net observations report
  16. EP260920a: Einstein Probe detection of an X-ray transient
  17. EP Alert 260919.40: Global MASTER-Net observations report
  18. GRB 260915A: VLT optical and near-infrared upper limits
  19. EP260917a: refined analysis of the EP-FXT observations
  20. IceCube-260919A - IceCube observation of a high-energy neutrino candidate track-like event
  21. The EP-WXT trigger 01709318491 is likely a flaring star
  22. EP260806a: Yamaguchi Interferometer radio detections
  23. EP260917a: SVOM/VT optical upper limits
  24. GRB 260918A: SVOM/C-GFT optical upper limits
  25. EP Alert 260918.62: Global MASTER-Net observations report
  26. Fermi GBM Sub-Threshold Detection of GRB 260918A
  27. EP Alert 260918.24: Global MASTER-Net observations report
  28. SVOM GRB260918.16: Global MASTER-Net observations report
  29. Konus-Wind detection of GRB 260916B (short/hard)
  30. The EP-WXT trigger 01709318279 is likely a flaring star
  31. GRB 260918A: SVOM/VT optical upper limits
  32. GRB 260916B: Glowbug gamma-ray detection of a short burst
  33. GRB 260918A: EP-FXT follow-up observation
  34. GRB 260917B: Mondy optical upper limit
  35. EP260917b: EP-WXT detection of an X-ray transient
  36. EP260917A: J-band upper limit with WINTER
  37. EP Alert 260917.32: Global MASTER-Net observations report
  38. GRB 260917B: EP-FXT follow-up observation
  39. EP260917a: COLIBRÍ optical upper limits
  40. GRB 260915A: Swift-XRT afterglow detection
  41. GRB 260918A: LCO optical upper limits
  42. EP260917a: Einstein Probe detection of an X-ray transient
  43. GRB 260918A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  44. GRB 260918A: SVOM detection of a burst
  45. GRB 260917C: Fermi GBM Final Real-time Localization
  46. GRB 260917B: FRAM-Auger optical limits
  47. GRB 260916B: Fermi GBM Detection
  48. IceCube-260916A: Upper limits from a search for additional neutrino events in IceCube
  49. GRB 260916B: Fermi GBM Final Localization
  50. GRB 260917A: Glowbug gamma-ray detection
  51. GRB 260915A: SVOM/ECLAIRs refined analysis
  52. GRB 260917B: WINTER J-band observations
  53. GRB 260917B: SVOM/VT optical observations
  54. SVOM GRB260917.16: Global MASTER-Net observations report
  55. GRB 260917B: LCO optical observation
  56. GRB 260917B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  57. GRB 260917B: SVOM detection of a faint burst
  58. GRB 260914A: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  59. GRB 260917A: BALROG localization (Fermi Trigger 811304653 / GRB 260917100)
  60. GRB 260917A: Fermi GBM Final Real-time Localization
  61. Fermi trigger No 811304653: Global MASTER-Net observations report
  62. The EP-WXT trigger 01709317235 is likely a flaring star
  63. GRB 260915A: J-band upper limit with WINTER
  64. Fermi trigger No 811264269: Global MASTER-Net observations report
  65. IceCube-260916A - IceCube observation of a high-energy neutrino candidate track-like event
  66. GRB 260909A: NOEMA detection
  67. GRB 260914A: SVOM/GRM observation
  68. GRB 260914A: Mondy and TShAO optical observations
  69. GRB 260914A: SVOM/ECLAIRs refined analysis
  70. GRB 260909A: Swift-XRT observations
  71. GRB 260916A: MAXI/GSC detection
  72. MAXI GRB260916.37: Global MASTER-Net observations report
  73. GRB 260915A: Swift ToO observations
  74. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  75. GRB 260915A: SVOM/C-GFT optical upper limits
  76. GRB 260915A: EP-FXT follow-up observation
  77. GRB 260915A: SVOM/VT refined early optical upper limits
  78. GRB 260915A: REM optical/NIR observations
  79. GRB 260914A: REM optical/NIR observations
  80. GRB 260914A: VLT/X-shooter observations and redshift confirmation
  81. GRB 260915A: SVOM/VT optical upper limits
  82. GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  83. GRB 260914A: VLT/X-shooter spectroscopic redshift z = 0.778
  84. GRB 260915A: 10.4m GTC deep optical limits
  85. GRB 260915A: NOT optical upper limit
  86. SVOM GRB260915.05: Global MASTER-Net observations report
  87. GRB 260915A: SVOM/VT optical upper limits from VHF data
  88. Fermi GBM Sub-Threshold Detection of GRB 260915A
  89. GRB 260915A: LCO optical upper limits
  90. EP Alert 260914.53: Global MASTER-Net observations report
  91. GRB 260914A: EP-FXT follow-up observation
  92. GRB 260915A: SVOM detection of a burst
  93. Fermi GBM Sub-Threshold Detection of GRB 260914A
  94. GRB 260914A: LCO optical observation
  95. GRB 260914A: SVOM/C-GFT optical observations
  96. GRB 260914A: SVOM/VT optical counterpart confirmation
  97. GRB 260914A: SVOM/VT optical observation from VHF data
  98. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  99. SVOM GRB260914.47: Global MASTER-Net observations report
  100. GRB 260914A: SVOM detection of a burst

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