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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"

22215 results found.

  1. EP251220a: Global MASTER-Net observations report
  2. SVOM GRB251220.98: Global MASTER-Net observations report
  3. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  4. GRB 251215A: Swift-XRT afterglow detection
  5. IceCube-251218A: COLIBRÍ optical upper limits
  6. SVOM GRB251219.11: Global MASTER-Net observations report
  7. IceCube Alert 251218.85: Global MASTER-Net observations report
  8. Fermi trigger No 787736968: Global MASTER-Net observations report
  9. Fermi GRB 251217A: Global MASTER-Net observations report
  10. GRB 251215A: Swift/UVOT Upper LImits
  11. Fermi GRB 251216A: Global MASTER-Net observations report
  12. GRB 251215A: COLIBRÍ optical upper limit
  13. GRB 251215A: Swift-XRT observations
  14. Fermi GRB 251215A: Global MASTER-Net observations report
  15. EP251214a: Optical upper limit with Kinder observations
  16. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  17. GRB 251214B: UAFO optical upper limit
  18. GRB 251214B: VLT/X-shooter observations
  19. GRB 251202A: radio detection with the VLA
  20. EP251214b: Global MASTER-Net observations report
  21. GRB 251214B: AbAO optical observations
  22. GRB 251214B: LCO detection of the optical counterpart
  23. GRB 251215A: Swift ToO observations
  24. EP251214b (EP trigger 01709250023): LCO optical limits
  25. GRB 251203B: AbAO optical observations
  26. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  27. GRB 251214B: Swift/UVOT Detection
  28. GRB 251214B: COLIBRÍ observations of the afterglow
  29. GRB 251214B: 1.3m DFOT optical detection
  30. EP251214a: Global MASTER-Net observations report
  31. GRB 251214B: Xinglong-2.16m optical observation
  32. GRB 251214B : MASTER optical afterglow detection
  33. Fermi trigger No 787396657: Global MASTER-Net observations report
  34. GRB 251214B: SVOM/C-GFT optical observations
  35. Swift GRB 251214B: Global MASTER-Net observations report
  36. Fermi GRB 251214A: Global MASTER-Net observations report
  37. EP251212a: Global MASTER-Net observations report
  38. EP251212a: KAIT optical upper limit
  39. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  40. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  41. Fermi GRB 251211B: Global MASTER-Net observations report
  42. IceCube-251210A: DDOTI Optical Upper Limit
  43. SVOM GRB251211.12: Global MASTER-Net observations report
  44. GRB 251205A: 1.3m DFOT optical upper limit
  45. IceCube Alert 251210.46: Global MASTER-Net observations report
  46. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  47. EP251130a: Mondy and AbAO optical observations
  48. Fermi GRB 251209A: Global MASTER-Net observations report
  49. Fermi GRB 251208C: Global MASTER-Net observations report
  50. GRB 251208B: Swift-XRT afterglow detection
  51. GRB 251208D: LAST optical upper limit
  52. GRB 251208D: LCO analysis of the XRT sources
  53. GRB 251208B: GROWTH-India Telescope optical upper limits
  54. GRB 251205A: J-band detection with WINTER
  55. GRB 251208D: Swift-XRT observations
  56. GRB 251129A: e-MERLIN C-band observations
  57. LAT GRB251208.43: Global MASTER-Net observations report
  58. GRB 251205A: Liverpool Telescope further optical follow-up observations
  59. SVOM GRB251208D: Global MASTER-Net observations report
  60. GRB 251208B: Swift ToO observations
  61. GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
  62. GRB 251205A: FTW optical and NIR observations
  63. EP-WXT trigger 01709249380: KAIT confirmation of a stellar flare
  64. GRB 251205A: Liverpool Telescope further optical follow-up observations
  65. SVOM GRB251206.86: Global MASTER-Net observations report
  66. GRB 251205A: ZTF and ATLAS optical afterglow detections
  67. GRB 251205A: GROWTH-India Telescope optical observations
  68. GRB 251205A: Swift/UVOT Detection
  69. GRB 251205A: Liverpool Telescope optical follow-up observations
  70. GRB 251203C: Swift/UVOT Upper Limit
  71. Konus-Wind detection of GRB 251118A
  72. GRB 251205A: Zeiss-1000 Koshka observatory optical observations
  73. GRB 251205A: COLIBRÍ optical observations
  74. GRB 251205A: GOTO optical afterglow detection
  75. GRB 251205A: NOT optical observations
  76. Swift GRB 251205A : MASTER OT detection with host galaxy
  77. Swift GRB251205A: Global MASTER-Net observations report
  78. GRB 251203C: SVOM/ECLAIRs refined analysis
  79. GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
  80. GRB 251203C: J-band observations with WINTER
  81. EP251130a: JinShan near-infrared observations
  82. GRB 251203C: SVOM/VT optical counterpart
  83. GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis
  84. GRB 251203B: Swift-XRT observations
  85. GRB 251203B : SVOM trigger sb25120304 is not a GRB
  86. GRB 251203B: LCO optical upper limits
  87. GRB 251203B: SVOM/VT optical observation
  88. GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations
  89. SVOM GRB251203.77: Global MASTER-Net observations report
  90. SVOM GRB251203B: Global MASTER-Net observations report
  91. GRB 251129A / EP251129a: SVOM/VT optical color bluer
  92. EP251130a: MAO/AZT-22 optical observations
  93. GRB 251202A / EP251202a: SVOM/VT optical observation
  94. EP251202a/GRB 251202A: KAIT optical observations
  95. EP251130a: ULL-ASTRO-MASTER late detection of the optical afterglow with LCO 1-m telescope at Teide Observatory
  96. Fermi GRB 251202B: Global MASTER-Net observations report
  97. GRB251129A/EP251129a: Swift UVOT detection
  98. GRB 251202A: Swift/UVOT Detection
  99. GRB 251201B: Kilonova-Catcher optical afterglow detection
  100. GRB 251201B: Swift/UVOT Detection

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