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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"
  1. GRB180914B: Swift UVOT position correction to circ. 23241
  2. GRB 180914B: AstroSat CZTI detection
  3. GRB 180914B : continued TSHAO optical observations
  4. GRB 180914A: AstroSat CZTI detection
  5. IPN Triangulation of GRB 180914A (long)
  6. GRB 180914B: VLT/X-shooter spectroscopic redshift
  7. GRB 180914B: MASTER OT automatic dtection
  8. GRB 180914B : TSHAO optical observations
  9. GRB 180914B: Continued RATIR Optical and NIR Observations
  10. GRB 180914B: AGILE/MCAL refined analysis
  11. GRB180914B: Swift UVOT detection of an optical afterglow
  12. Konus-Wind of the very bright GRB 180914B
  13. GRB 180914B: Optical counterpart observation from OAJ
  14. GRB 180914B: RATIR Optical and NIR Observations
  15. GRB 180914B: KAIT Optical Afterglow Candidate
  16. GRB 180914B: Swift-XRT afterglow detection
  17. GRB 180914A: RATIR Optical and NIR Observations
  18. GRB 180914B: Tiled Swift observations
  19. GRB 180914B: Fermi-LAT detection
  20. GRB 180914B: AGILE/GRID detection
  21. GRB 180914A: MASTER automatic inspection
  22. GRB 180914A: Swift-XRT observations
  23. GRB 180914A: Tiled Swift observations
  24. GRB 180914A: Fermi GBM detection
  25. GRB 180914B: AGILE/MCAL detection of a burst
  26. GRB 180914A: Fermi-LAT detection
  27. IceCube-180908A: CALET Gamma-Ray Burst Monitor upper limits
  28. Fermi-LAT Gamma-ray Observations of IceCube-180908A
  29. INTEGRAL observation of IceCube-180908A
  30. Search for counterparts to IceCube-180908A with IceCube
  31. IceCube-180908A: HAWC follow-up
  32. Search for counterpart to IceCube-180908A with ANTARES
  33. GRB 180715A: 15 GHz upper limits from the AMI Short GRB Program
  34. GRB 180718A: 15 GHz upper limits from the AMI Short GRB Program
  35. GRB 180905A: Swift/UVOT Upper Limits
  36. IceCube-180908A - IceCube observation of a high-energy neutrino candidate event
  37. GRB 180905A, Swift-BAT refined analysis
  38. GRB 180905A: RATIR Optical and NIR Observations
  39. GRB 180905A: MITSuME Akeno optical upper limits
  40. GRB 180905A: Swift-XRT refined Analysis
  41. GRB 180904A: BOOTES-2/TELMA early observations
  42. GRB 180905A: BOOTES-3/YA optical observations
  43. GRB 180905A: Enhanced Swift-XRT position
  44. GRB 180904A: AbAO optical upper limit
  45. GRB 180904A: Swift/UVOT Upper Limits
  46. GRB 180904A: RATIR Optical and NIR Observations
  47. GRB 180904A: Swift-BAT refined analysis
  48. Fermi GBM trigger 557852757/180905629 is not a GRB
  49. GRB 180905A: Swift detection of a burst
  50. GRB 180904A: Swift-XRT refined Analysis
  51. GRB 180904A: LT early observations
  52. GRB 180904A: SAO RAS optical observations
  53. GRB 180904A: OSN observations
  54. GRB 180904A: Enhanced Swift-XRT position
  55. GRB 180904A: NOT optical observations, candidate host galaxy
  56. GRB 180904A: Swift detection of a burst
  57. Konus-Wind observation of GRB 180828A
  58. GRB 180829A: Swift-XRT observations
  59. GRB 180828A: AstroSat CZTI detection
  60. GRB 180828A: Swift/UVOT Upper Limits
  61. GRB 180828A: RATIR Optical and NIR Observations
  62. GRB 180828A: Swift-BAT refined analysis
  63. GRB 180829A: Tiled Swift observations
  64. GRB 180829A/MAXI J0406-019: MAXI/GSC detection
  65. GRB 180828A: Swift-XRT refined Analysis
  66. GRB 180828A / Swift J1754.9-2548: Enhanced Swift-XRT position
  67. GRB 180828A: Fermi GBM observation
  68. GRB 180828A: Swift detection of a GRB or possible Galactic Transient Swift J1754.9-2548
  69. GRB 180728A: classification of the associated SN 2018fip
  70. Konus-Wind observation of GRB 180824A
  71. Fermi GBM trigger 557014342/180826925 is not a GRB
  72. Fermi GBM trigger 557008382/180826856 is not a GRB
  73. GRB 180818B: TSHAO optical upper limit
  74. GRB 180824A: MASTER inspection IPN short GRB error box
  75. GRB 180823A, Swift-BAT refined analysis
  76. IPN Triangulation of GRB 180824A (short)
  77. GRB 180823A: Swift/UVOT Upper Limits
  78. GRB 180823A: RATIR Optical and NIR Observations
  79. GRB 180823A: Swift-XRT refined Analysis
  80. GRB 180823A: Enhanced Swift-XRT position
  81. GRB 180823A: Swift detection of a burst
  82. GRB 180821A: VLT observations
  83. GRB 180821A: Swift/UVOT Upper Limits
  84. GRB 180821A: Swift-BAT refined analysis
  85. GRB 180821A: iTelescope counterpart is not the afterglow
  86. GRB 180821A: Swift-XRT refined Analysis
  87. GRB 180821A: LCO Siding Springs observations
  88. GRB 180821A: Enhanced Swift-XRT position
  89. GRB 180818B: 1.5m OSN optical afterglow candidate
  90. GRB 180821A: iTelescope optical afterglow detection
  91. GRB 180821A: BOOTES-3/YA optical observations
  92. GRB 180821A: Swift detection of a burst
  93. GRB180806A: confirmation of the X-ray afterglow
  94. GRB 180818B: Swift-XRT refined Analysis
  95. GRB 180818B: Swift-BAT refined analysis
  96. GRB 180818A: Swift-BAT refined analysis
  97. GRB 180818B: Fermi GBM observations
  98. GRB 180818B: Swift/UVOT Upper Limits
  99. GRB 180818B: Enhanced Swift-XRT position
  100. GRB 180818A: Swift/UVOT Upper Limits

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