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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"

37221 results found.

  1. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  2. GRB 251116C: Swift-XRT observations
  3. GRB 251117A: Fermi GBM Final Localization Correction
  4. GRB 251116D: Glowbug gamma-ray detection
  5. EP251023a: Assy AZT-20 optical observations
  6. EP251023a: UAFO and AbAO optical observations
  7. GRB 251116D: AstroSat CZTI detection
  8. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  9. GRB 251116C: SVOM/VT optical upper limit
  10. GRB 251025B: further Mondy optical observations
  11. GRB 251111A: Mondy optical upper limit
  12. GRB 251116B: EP-FXT follow-up observation
  13. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  14. GRB 251116B: LCO optical upper limits
  15. GRB 251116C: LCO optical upper limits
  16. GRB 251116C: SVOM detection of a burst
  17. GRB 251116B: SVOM detection of a burst
  18. GRB 251116A: Fermi GBM Final Real-time Localization
  19. GRB 251115A: Tiled Swift observations
  20. GRB 251115A: Fermi-LAT detection
  21. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  22. Fermi GRB 251115A: Global MASTER-Net observations report
  23. GRB 251115A: Fermi GBM Final Real-time Localization
  24. GRB 251113A: Glowbug gamma-ray detection
  25. GRB 251113A: AstroSat CZTI detection
  26. GRB 251114B: Fermi GBM Final Real-time Localization
  27. GRB 251112A: Swift-BAT refined analysis
  28. Konus-Wind detection of GRB 251108C
  29. Konus-Wind detection of GRB 251103A
  30. IPN triangulation of GRB 251108C
  31. Fermi GRB 251114A: Global MASTER-Net observations report
  32. GRB 251114A: Fermi GBM Final Real-time Localization
  33. Fermi GRB 251113A: Global MASTER-Net observations report
  34. GRB 251113A: BALROG localization (Fermi Trigger 784748255 / GRB 251113734)
  35. GRB 251113A: Fermi GBM Final Real-time Localization
  36. GRB 251111A: SVOM/ECLAIRs refined analysis
  37. GRB 251025B: SVOM/ECLAIRs refined analysis
  38. Fermi Gamma-ray Burst Monitor trigger 784717756/251113381 is not a GRB
  39. GRB 251112A: Swift/UVOT Upper Limits
  40. LIGO/Virgo/KAGRA S251112cm: ATLAS pre-detections of AT2025adgp and AT2025adgq
  41. GRB 251112A: Swift-XRT refined Analysis
  42. GRB 251108C: AstroSat CZTI detection
  43. LIGO/Virgo/KAGRA S251112cm: Detection of two young transients by BlackGEM/MeerLICHT: AT2025adgp and AT2025adgq
  44. GRB 251112B: MAXI/GSC detection
  45. Fermi Gamma-ray Burst Monitor trigger 784687703/251113034 is not a GRB
  46. Fermi Gamma-ray Burst Monitor trigger 784687099/251113027 is not a GRB
  47. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  48. GRB 251108B: Glowbug gamma-ray detection
  49. Swift Trigger 1413695: a possible GRB 251112A
  50. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  51. Fermi Gamma-ray Burst Monitor trigger 784653403/251112637 is not a GRB
  52. GRB 251106B: Glowbug gamma-ray detection of a likely short burst
  53. GRB 251111A: Swift-XRT afterglow detection
  54. GRB 251111A: SVOM/VT optical observations with X-band data
  55. GRB 251111A: Swift-XRT observations
  56. GRB 251111A: EP-FXT counterpart detection
  57. GRB 251013C: Chandra X-ray observations and jet break detection
  58. GRB 251111A: SVOM/VT optical observations with VHF data
  59. GRB 251111A: KAIT optical upper limit
  60. GRB 251111A: LCO optical observation
  61. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  62. GRB 251111A: SVOM detection of a soft burst
  63. GRB 251103B: Swift-BAT refined analysis
  64. GRB 251106A: Swift/UVOT Upper Limits
  65. GRB 251105B: Insight-HXMT/HE detection
  66. GRB 251106B: Insight-HXMT detection
  67. GRB 251105A: AstroSat CZTI detection
  68. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  69. GRB 251108A: Fermi GBM Final Localization Correction
  70. GRB 251102B: SVOM/GRM observation
  71. Fermi Gamma-ray Burst Monitor trigger 784279167/251108305 is not a GRB
  72. IPN triangulation of GRB 251105B (possible sGRB with EE)
  73. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  74. GRB 251106B: SVOM/GRM observation of a short burst
  75. GRB 251106A: Swift-XRT afterglow detection
  76. GRB 251106A: Kilonova-Catcher optical upper limit
  77. Fermi GBM Sub-Threshold Detection of GRB 251106A
  78. GRB 251106A: Swift/BAT arcminute localization of a burst
  79. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  80. GRB 251106A: MASTER optical observations
  81. GRB 251106A: SVOM detection of a burst
  82. GRB 251103B: AstroSat CZTI detection
  83. GRB 251025C: TERI Gamma-ray detection
  84. GRB 251016B: TERI Gamma-ray detection
  85. GRB 251016A: TERI Gamma-ray detection of a short burst
  86. GRB 250920C: TERI Gamma-ray detection
  87. Fermi Gamma-ray Burst Monitor trigger 784109140/251106337 is not a GRB
  88. GRB 251105A: Fermi GBM Observation
  89. GRB 251105C: Fermi GBM Final Localization Correction
  90. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  91. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  92. GRB 251105B: AstroSat CZTI detection of a short burst with extended emission
  93. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  94. Fermi GBM Sub-Threshold Detection of GRB 251105B
  95. GRB 251103B: Swift/UVOT Upper Limits
  96. GRB 251105B: SVOM/GRM observation of a possible short burst with extended emission
  97. Fermi GRB 251105A: Global MASTER-Net observations report
  98. GRB 251105A: Fermi GBM Final Real-time Localization
  99. Fermi Gamma-ray Burst Monitor trigger 783986701/251104920 is not a GRB
  100. GRB 251103B: Fermi GBM observation

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