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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"

42975 results found.

  1. GRB 251214D: GECAM-B observation of a long burst
  2. GRB 251214B: Fermi GBM Observation
  3. GRB 251209A: Insight-HXMT/HE detection
  4. GRB 251215A: Swift ToO observations
  5. EP251214b (EP trigger 01709250023): LCO optical limits
  6. GRID detection of GRB 251213A
  7. GRB 251203B: AbAO optical observations
  8. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  9. GRB 251214B: GECAM-B observation of a long burst
  10. GRB 251214B: Swift-XRT refined Analysis
  11. GRB 251213A: SVOM/GRM observation
  12. EP251214a: KAIT optical upper limit
  13. GRB 251214D: AstroSat CZTI detection of a long burst
  14. GRB 251213A: AstroSat CZTI detection
  15. GRB 251214A: AstroSat CZTI detection
  16. GRB 251213A: GECAM-B detection
  17. GRB 251214B: Swift/UVOT Detection
  18. GRB 251215A: Fermi GBM Final Real-time Localization
  19. GRB 251214B: COLIBRÍ observations of the afterglow
  20. EP251214a: EP-FXT non-detection and upper limit
  21. GRB 251214A: GECAM-B observation of a likely long burst
  22. GRB 251214B: 1.3m DFOT optical detection
  23. EP251214a: Global MASTER-Net observations report
  24. GRB 251214B: Enhanced Swift-XRT position
  25. GRB 251214B: Xinglong-2.16m optical observation
  26. GRB 251214C: Fermi GBM Final Localization
  27. GRB 251214B : MASTER optical afterglow detection
  28. Fermi trigger No 787396657: Global MASTER-Net observations report
  29. GRB 251214B: SVOM/C-GFT optical observations
  30. EP251214a: COLIBRÍ optical upper limit
  31. Swift GRB 251214B: Global MASTER-Net observations report
  32. EP251214.305: COLIBRÍ optical upper limit
  33. GRB 251214B: Swift detection of a burst with an optical counterpart
  34. GRB 251214B: Fermi GBM Final Real-time Localization
  35. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  36. Fermi GRB 251214A: Global MASTER-Net observations report
  37. GRB 251214A: Fermi GBM Final Real-time Localization
  38. EP251212a: Global MASTER-Net observations report
  39. EP251212a: KAIT optical upper limit
  40. EP251212a / GRB 251212A: AstroSat CZTI detection
  41. EP251212a: EP-FXT follow-up observation
  42. GRB 251211B: AstroSat CZTI detection
  43. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  44. GRB 251209A: NuSTAR detection of prompt emission
  45. EP251212a : COLIBRÍ optical upper limit
  46. EP251212a: Einstein Probe detection of an X-ray transient
  47. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  48. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  49. Fermi GRB 251211B: Global MASTER-Net observations report
  50. GRB 251211B: Fermi GBM Final Real-time Localization
  51. IceCube-251210A: DDOTI Optical Upper Limit
  52. SVOM GRB251211.12: Global MASTER-Net observations report
  53. GRB 251211A: Fermi GBM Final Real-time Localization
  54. GRB 251209A: Fermi GBM observation
  55. GRB 251205A: 1.3m DFOT optical upper limit
  56. GRB 251209A: AstroSat CZTI detection
  57. IceCube Alert 251210.46: Global MASTER-Net observations report
  58. IceCube-251210A - IceCube observation of a high-energy neutrino candidate track-like event
  59. EP251124a: Mondy optical upper limit
  60. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  61. EP251130a: Mondy and AbAO optical observations
  62. GRB 251208A: AstroSat CZTI detection
  63. Fermi GBM Sub-Threshold Detection of GRB 251205A
  64. GRB 251208A: Glowbug gamma-ray detection
  65. GRB 251208B: COLIBRÍ optical upper limits
  66. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  67. GRB 251208C: GECAM-B observation of a short burst
  68. GRB 251208A: GECAM-B observation of a short burst
  69. Fermi GRB 251209A: Global MASTER-Net observations report
  70. Fermi GRB 251208C: Global MASTER-Net observations report
  71. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  72. GRB 251208B: Swift-XRT afterglow detection
  73. GRB 251208D: LAST optical upper limit
  74. GRB 251209A: Fermi GBM Final Real-time Localization
  75. GRB 251208D: LCO analysis of the XRT sources
  76. GRB 251208B: Fermi GBM Observation
  77. GRB 251208B: GROWTH-India Telescope optical upper limits
  78. GRB 251205A: J-band detection with WINTER
  79. GRB 251208D: Swift-XRT observations
  80. GRB 251208A: SVOM/GRM observation of a short burst
  81. GRB 251208C: SVOM/GRM observation of a short burst
  82. GRB 251129A: e-MERLIN C-band observations
  83. LAT GRB251208.43: Global MASTER-Net observations report
  84. GRB 251205A: Liverpool Telescope further optical follow-up observations
  85. GRB 251208D: LCO optical upper limits
  86. SVOM GRB251208D: Global MASTER-Net observations report
  87. GRB 251208B: Swift ToO observations
  88. GRB 251208B: Fermi-LAT detection
  89. GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
  90. GRB 251208D: SVOM possible detection of a faint burst
  91. GRB 251206A: SVOM detection of a burst through offline search
  92. GRB 251208C: Fermi GBM Final Real-time Localization
  93. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  94. GRB 251208B: Fermi GBM Final Real-time Localization
  95. GRB 251208A: Fermi GBM Final Real-time Localization
  96. GRB 251205A: FTW optical and NIR observations
  97. EP-WXT trigger 01709249380: KAIT confirmation of a stellar flare
  98. GRB 251205A: Liverpool Telescope further optical follow-up observations
  99. SVOM GRB251206.86: Global MASTER-Net observations report
  100. EP-WXT trigger 01709249380: confirmation of a stellar flare by BOOTES-5

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