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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"

37712 results found.

  1. GRB 251113A: BALROG localization (Fermi Trigger 784748255 / GRB 251113734)
  2. GRB 251113A: Fermi GBM Final Real-time Localization
  3. GRB 251111A: SVOM/ECLAIRs refined analysis
  4. GRB 251025B: SVOM/ECLAIRs refined analysis
  5. Fermi Gamma-ray Burst Monitor trigger 784717756/251113381 is not a GRB
  6. GRB 251112A: Swift/UVOT Upper Limits
  7. GRB 251112A: Swift-XRT refined Analysis
  8. GRB 251108C: AstroSat CZTI detection
  9. GRB 251112B: MAXI/GSC detection
  10. Fermi Gamma-ray Burst Monitor trigger 784687703/251113034 is not a GRB
  11. Fermi Gamma-ray Burst Monitor trigger 784687099/251113027 is not a GRB
  12. GRB 251108B: Glowbug gamma-ray detection
  13. Swift Trigger 1413695: a possible GRB 251112A
  14. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  15. Fermi trigger No 784621743: Global MASTER-Net observations report
  16. Fermi Gamma-ray Burst Monitor trigger 784653403/251112637 is not a GRB
  17. GRB 251106B: Glowbug gamma-ray detection of a likely short burst
  18. GRB 251111A: Swift-XRT afterglow detection
  19. GRB 251111A: SVOM/VT optical observations with X-band data
  20. GRB 251111A: Swift-XRT observations
  21. GRB 251111A: EP-FXT counterpart detection
  22. GRB 251013C: Chandra X-ray observations and jet break detection
  23. GRB 251111A: SVOM/VT optical observations with VHF data
  24. GRB 251111A: KAIT optical upper limit
  25. GRB 251111A: LCO optical observation
  26. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  27. GRB 251111A: SVOM detection of a soft burst
  28. GRB 251103B: Swift-BAT refined analysis
  29. GRB 251106A: Swift/UVOT Upper Limits
  30. GRB 251105B: Insight-HXMT/HE detection
  31. GRB 251106B: Insight-HXMT detection
  32. GRB 251105A: AstroSat CZTI detection
  33. GRB 251108A: Fermi GBM Final Localization Correction
  34. Fermi trigger No 784329591: Global MASTER-Net observations report
  35. Fermi trigger No 784279167: Global MASTER-Net observations report
  36. GRB 251102B: SVOM/GRM observation
  37. Fermi Gamma-ray Burst Monitor trigger 784279167/251108305 is not a GRB
  38. IPN triangulation of GRB 251105B (possible sGRB with EE)
  39. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  40. GRB 251106B: SVOM/GRM observation of a short burst
  41. GRB 251106A: Swift-XRT afterglow detection
  42. GRB 251106A: Kilonova-Catcher optical upper limit
  43. Fermi GBM Sub-Threshold Detection of GRB 251106A
  44. GRB 251106A: Swift/BAT arcminute localization of a burst
  45. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  46. GRB 251106A: MASTER optical observations
  47. GRB 251106A: SVOM detection of a burst
  48. GRB 251103B: AstroSat CZTI detection
  49. GRB 251025C: TERI Gamma-ray detection
  50. GRB 251016B: TERI Gamma-ray detection
  51. GRB 251016A: TERI Gamma-ray detection of a short burst
  52. GRB 250920C: TERI Gamma-ray detection
  53. Fermi trigger No 784034269: Global MASTER-Net observations report
  54. Fermi Gamma-ray Burst Monitor trigger 784109140/251106337 is not a GRB
  55. GRB 251105A: Fermi GBM Observation
  56. GRB 251105C: Fermi GBM Final Localization Correction
  57. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  58. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  59. GRB 251105B: AstroSat CZTI detection of a short burst with extended emission
  60. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  61. Fermi GBM Sub-Threshold Detection of GRB 251105B
  62. GRB 251103B: Swift/UVOT Upper Limits
  63. GRB 251105B: SVOM/GRM observation of a possible short burst with extended emission
  64. Fermi GRB 251105A: Global MASTER-Net observations report
  65. GRB 251105A: Fermi GBM Final Real-time Localization
  66. Fermi Gamma-ray Burst Monitor trigger 783986701/251104920 is not a GRB
  67. GRB 251103B: Fermi GBM observation
  68. GRB 251104A: SVOM detection of a burst
  69. GRB 251028A: Insight-HXMT/HE detection
  70. GRB 251103A: Optical afterglow detection by ZTF’s public survey
  71. GRB 251103A: WFST optical observations
  72. EP251102a: OHP/T193 optical observations
  73. GRB 251103A: OHP/T193 optical observations
  74. GRB 251103A: Xinglong 2.16m optical detection
  75. GRB 251103A: Insight-HXMT detection
  76. GRB 251103A: KAIT optical observations
  77. GRB 251103B: Nanshan/HMT optical upper limit
  78. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  79. GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
  80. GRB 251103B: MITSuME Akeno optical upper limits
  81. GRB 251103B: Swift-XRT refined Analysis
  82. Fermi GRB 251103A: Global MASTER-Net observations report
  83. GRB 251103A: J-band detection with WINTER
  84. Swift GRB 251103B: Global MASTER-Net observations report
  85. GRB 251103B: GROWTH-India Telescope optical upper limits
  86. GRB 251103A: Kilonova-Catcher optical afterglow detection
  87. GRB 251103B: Enhanced Swift-XRT position
  88. GRB 251103B: Prompt enhanced Swift-XRT position
  89. GRB 251103B: Swift detection of a burst
  90. GRB 251103B: Fermi GBM Final Real-time Localization
  91. GRB 251103A: Swift/UVOT Detection
  92. GRB 251103A: Fermi GBM Observation
  93. GRB 251103A: SVOM/GRM observation
  94. GRB 251103A: Swift-XRT afterglow detection
  95. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  96. GRB 251025B: OHP/T193 optical upper limit
  97. GRB 251103A: LCO optical observation
  98. GRB 251103A: GOTO optical afterglow detection
  99. GRB 251102A: AstroSat CZTI detection
  100. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart

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