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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"

37162 results found.

  1. EP260116a: COLIBRÍ detection of a fading optical source
  2. GRB 251208D: SVOM/ECLAIRs refined analysis
  3. GRB 251208D: SVOM/ECLAIRs refined analysis
  4. GRB 260117A: Swift-XRT afterglow detection
  5. GRB 260115A: AstroSat CZTI detection
  6. GRB 260117A: ZTSh optical upper limit
  7. GRB 260110A: SVOM detection of a burst through offline search
  8. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  9. GRB 260117A: SVOM/VT optical candidate
  10. GRB 260117A: SVOM/C-GFT upper limit
  11. GRB 260117A: Swift-XRT observations
  12. GRB 260117A: Swift ToO observations
  13. GRB 260117A: SVOM detection of a long faint burst
  14. GRB 260115A: GECAM-B observation
  15. GRB 260114A: VLT/MUSE spectroscopic observations
  16. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  17. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  18. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  19. Fermi GRB 260115A: Global MASTER-Net observations report
  20. GRB 260115A: Fermi GBM Final Real-time Localization
  21. GRB 251222A: radio detection with the VLA
  22. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  23. Konus-Wind detection of GRB 260114A
  24. GRB 260114A: Swift-XRT refined Analysis
  25. GRB 260114A: 6 GHz VLA observations
  26. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  27. GRB 260114A : MITSuME Akeno optical upper limits
  28. GRB 260114A: COLIBRÍ optical upper limits
  29. GRB 260114A: TNG NIR upper limit
  30. GRB 260114A: NOT optical observations
  31. Konus-Wind detection of GRB 251230A / EP251230a
  32. GRB 260114A: SVOM/GRM observation of a short burst
  33. Swift GRB 260114A: Global MASTER-Net observations report
  34. GRB 260114A: GECAM-B observation of a short burst
  35. GRB 260114A: Mondy optical observations
  36. GRB 260114A: Fermi GBM observation
  37. GRB 260112B: GECAM-B observation
  38. GRB 260114A: GMG Optical Observation
  39. GRB 260114A: Swift detection of a short burst
  40. GRB 260114A: Fermi GBM Final Real-time Localization
  41. Konus-Wind detection of GRB 260101A
  42. GRB 260111A: Swift-XRT observations
  43. Swift Trigger 1439093: is probably not GRB 260113A
  44. GRB 260111A: COLIBRÍ optical afterglow candidate
  45. GRB 260111A: GECAM-B observation of a burst
  46. GRB 260111A: Fermi GBM Observation
  47. Swift Trigger 1434591 is not a GRB
  48. GRB 260111A: GOTO optical upper limits
  49. GRB 260112B: Fermi GBM Final Real-time Localization
  50. GRB 260111A: Swift ToO observations
  51. GRB 251230A: Mondy Optical Observations
  52. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  53. GRB 260112A: Fermi GBM Final Real-time Localization
  54. Fermi GRB 260111A: Global MASTER-Net observations report
  55. GRB 260111A: Fermi GBM Final Real-time Localization
  56. EP260110a: KAIT optical upper limit
  57. EP260110a: BOOTES-5/JGU optical upper limit
  58. GRB 260109C: LCO optical upper limits
  59. GRB 260109C: Kilonova-Catcher optical upper limit
  60. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  61. Swift Trigger 1434591: possible GRB 260109C
  62. GRB 260109B: Fermi GBM Final Real-time Localization
  63. GRB 260102A: Swift-XRT afterglow detection
  64. GRB 260109A: Fermi GBM Final Real-time Localization
  65. GRB 260104A: Swift-BAT refined analysis
  66. GRB 260101A: Swift-BAT refined analysis
  67. Swift GRB 251230A: Global MASTER-Net OT detection
  68. Fermi GRB 260107A: Global MASTER-Net observations report
  69. GRB 260102A: AbAO optical observations
  70. GRB 260107A: Fermi GBM Final Real-time Localization
  71. Fermi GRB 260105A: Global MASTER-Net observations report
  72. GRB 260105B: Fermi GBM Detection
  73. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  74. GRB 260105A: SVOM/GRM observation
  75. GRB 260105B: SVOM/GRM observation
  76. Fermi GRB 260105B: Global MASTER-Net observations report
  77. GRB 260105B: Fermi GBM Final Real-time Localization
  78. GRB 260105A: Fermi GBM Final Real-time Localization
  79. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  80. GRB 260101A: COLIBRÍ optical upper limits
  81. GRB 260103A: Insight-HXMT/HE detection
  82. GRB 260104A: COLIBRÍ optical upper limits
  83. GRB 260104C: Fermi GBM Final Real-time Localization
  84. Fermi GRB 260104B: Global MASTER-Net observations report
  85. Swift GRB 260104A: Global MASTER-Net observations report
  86. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  87. GRB 260104A: Swift-XRT refined Analysis
  88. GRB 260104A: Enhanced Swift-XRT position
  89. GRB 260101A: Swift/UVOT Detection
  90. GRB 260103A: GECAM-B observation of a burst
  91. GRB 260104B: Fermi GBM Final Localization
  92. GRB 260104A: Swift detection of a burst
  93. GRB 260103A: SVOM/GRM observation of a possible GRB
  94. GRB 260101A: COLIBRÍ optical observations
  95. GRB 260102B: Fermi GBM Final Real-time Localization
  96. Fermi GBM Sub-Threshold Detection of GRB 260102A
  97. GRB 260102A: EP-FXT follow-up observation
  98. GRB 260102A: LCO optical upper limits
  99. GRB 260102A: Swift-XRT observations
  100. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations

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