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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

28057 results found.

  1. GRB 190204A: COATLI Optical Detection of the Fading Afterglow
  2. GRB 190203A: Liverpool Telescope near-IR observations
  3. GRB 190203A: Swift-XRT refined Analysis
  4. GRB 190204A: Swift-XRT refined Analysis
  5. Swift Trigger 887541: MASTER inspect
  6. GRB 190204A: MAXI/GSC detection
  7. GRB 190202A: R and I band observation from HCT
  8. GRB 190204A: Swift detection of a burst with a possible optical counterpart
  9. GRB 190203A: MASTER OT detection
  10. Swift Trigger 887541: Swift detection of Swift J1728.9-3613
  11. GRB 190203A: Enhanced Swift-XRT position
  12. GRB 190203A: SAO RAS optical observations, afterglow fading
  13. GRB 190203A: Koshka Zeiss-1000 optical upper limit
  14. GRB 190203A: Swift detection of a burst with an optical counterpart
  15. GRB 190202A: SAO RAS optical observations
  16. GRB 190202A: TSHAO optical observations
  17. GRB 190202A: Swift-XRT refined Analysis
  18. GRB 190202A: LCO-CTIO optical observations
  19. GRB 190202A: Fermi GBM observation
  20. GRB 190202A, Swift-BAT refined analysis
  21. GRB 190202A: Swift/UVOT Detection
  22. GRB 190202A: GOTO optical observations
  23. GRB 190202A: Enhanced Swift-XRT position
  24. GRB 190202A: Koshka Zeiss-1000 optical observations
  25. GRB 190202A: Swift detection of a burst with an optical counterpart
  26. Fermi GBM trigger 570716645/190201517 is not a GRB
  27. GRB 190131A: Insight-HXMT/HE detection
  28. GRB 190129B: Insight-HXMT/HE detection
  29. GRB 190129B: DDOTI Detection of the Possible Afterglow and Suggestion of Fading
  30. GRB 190129B: Swift/UVOT Upper Limits
  31. GRB 190129B: ePESSTO NTT optical observations
  32. GRB 190129B: MASTER Global Robotic Net optical observation
  33. GRB 190129B: GROND possible host candidate
  34. GRB 190129B: Swift-XRT candidate afterglow detection
  35. Fermi GBM Observations of IceCube-190124A
  36. GRB 190129A: Fermi GBM detection
  37. INTEGRAL observation of IceCube-190124A
  38. GRB 190129A: MAXI/GSC detection
  39. Trigger 886496: Another Swift trigger on MAXI J1348-630
  40. Trigger 886486: Swift detection of MAXI J1631-479
  41. Trigger 886266: Another Swift trigger on MAXI J1348-630
  42. GRB 190114C: Optical follow-up from HCT
  43. Swift Trigger 885960: A third Swift trigger on MAXI J1348-630
  44. Trigger 885807: Swift detection of MAXI J1348-630
  45. Search for counterparts to IceCube-190124A with IceCube
  46. Search for counterpart to IceCube-190124A with ANTARES
  47. Fermi-LAT Gamma-ray Observations of IceCube-190124A
  48. GRB 190123A: IKI-GRB-FuN optical upper limit
  49. GRB 190123A: NEXT-0.6m optical limit
  50. GRB 190114C: CHILESCOPE optical observations
  51. GRB 190123A: AROMA-N Optical Observation
  52. GRB 190123A: Swift/UVOT Upper Limits
  53. GRB 190123A: COATLI Optical Observations
  54. GRB 190123A: Swift-BAT refined analysis
  55. GRB 190123A: GMG observational limit
  56. Trigger 885456: Swift detection of MAXI J1631-479
  57. GRB 190123A: Swift-XRT refined Analysis
  58. GRB 190123A: GOTO optical limit
  59. GRB 190123A: Fermi GBM observation
  60. GRB 190123A: Enhanced Swift-XRT position
  61. GRB 190123A: MASTER Global Robotic Net optical observation
  62. GRB 190123A: Swift detection of a burst
  63. GRB 190122A: Fermi GBM observation
  64. GRB 190122A: Fermi-LAT detection
  65. GRB 190114C: RTT150 optical observations
  66. IPN Triangulation of GRB 190118A (long)
  67. IPN Triangulation of GRB 190117A (long)
  68. Trigger 884906: Swift detection of MAXI J1631-479
  69. GRB 190114C: GMRT detection at 1.26GHz
  70. GRB 190114C: MeerKAT radio observation
  71. GRB 190117A: Insight-HXMT/HE detection
  72. Swift ToO Website Down
  73. GRB 190114C: RATIR Optical and NIR Detections
  74. GRB 190114C: RT-22 detection at 36.8 GHz
  75. GRB 190114C: COATLI Optical Detection
  76. GRB 190114C: continued CHILESCOPE optical obs
  77. GRB190114C: ATCA detection of the radio afterglow
  78. GRB 190114B: continued optical observations in Mondy
  79. GRB 190114C: Optical detection from HCT
  80. GRB 190114C: CHILESCOPE optical observations
  81. Konus-Wind observation of GRB 190114C
  82. GRB190114C, Long follow up urged
  83. GRB190114C: GRowth-India detection of optical afterglow
  84. GRB 190114B: Swift-XRT refined Analysis
  85. GRB 190114C: REM optical/NIR detection
  86. GRB 190114C: Mondy optical observations
  87. GRB 190114C: Swift/UVOT Detection
  88. GRB 190114C: Swift-BAT refined analysis
  89. GRB 190114B: Liverpool Telescope near-IR observations
  90. GRB 190114B: optical afterglow observations in Mondy and Abastumani observatories
  91. GRB 190114B, Swift-BAT refined analysis
  92. GRB 190114B: Swift/UVOT Upper Limits
  93. GRB 190114A: Swift/UVOT Observations
  94. GRB 190114A: Mondy optical afterglow detectio
  95. GRB 190114C:Insight-HXMT/HE detection
  96. GRB 190114C: A type 1 BdHN with TeV emission
  97. GRB 190114C: AGILE/MCAL detection
  98. GRB 190114C: Fermi-LAT detection
  99. GRB 190114C: Fermi GBM detection
  100. GRB 190114C: Swift-XRT refined Analysis

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