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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. GRB 181002A: Swift detection of a burst
  2. Trigger 864882: Swift detection of Crab in its normal state
  3. GRB 180914B: RTT150 optical observations
  4. GRB 180914B: RTT150 optical observations
  5. GRB 180930A: Swift-BAT refined analysis
  6. GRB 180930A: Swift-XRT refined Analysis
  7. GRB 180930A: NOT optical upper limits
  8. GRB 180930A: Swift/UVOT Upper Limits
  9. GRB 180930A: Enhanced Swift-XRT position
  10. GRB 180930A: KAIT Optical Upper Limit
  11. GRB 180930A: Prompt enhanced Swift-XRT position
  12. GRB 180930A: Swift detection of a burst
  13. INTEGRAL detections of the prompt gamma-ray emission of GRB 180914B
  14. GRB 180924A: Swift/UVOT Upper Limits
  15. GRB 180925A: VLT optical observations
  16. GRB 180925A: Insight-HXMT/HE detection
  17. GRB 180925A: Swift/UVOT Detection
  18. GRB 180925A: Swift-BAT refined analysis
  19. GRB 180925A: Swift-XRT refined Analysis
  20. GRB 180925A: Enhanced Swift-XRT position
  21. GRB 180925A: Prompt enhanced Swift-XRT position
  22. Konus-Wind observation of GRB 180923A
  23. GRB 180925A: Swift detection of a burst
  24. GRB 180924A: MASTER inspection
  25. GRB 180924A: Swift-XRT refined Analysis
  26. GRB 180923B - GBM Correction to GCN 23263
  27. GRB 180924A: Swift-BAT refined analysis
  28. GRB 180923B: Fermi GBM detection
  29. GRB 180924A: Enhanced Swift-XRT position
  30. GRB 180924A: Swift detection of a burst
  31. Swift Trigger 863053 is not an astrophysical event
  32. GRB 180923A: CALET Gamma-Ray Burst Monitor detection
  33. GRB 180923A: MASTER inspection MAXI/GSC error box
  34. GRB 180923A: MAXI/GSC detection
  35. GRB 180914B: OSN Detection and light curve/SED analysis
  36. GRB 180914B: OAJ multi-color follow-up
  37. Konus-Wind observation of GRB 180914A
  38. GRB 180914B: DDOTI/OAN Detection and Confirmation of Fading
  39. GRB 180914B: GOTO optical detection
  40. GRB180914B: Swift UVOT position correction to circ. 23241
  41. GRB 180914B: AstroSat CZTI detection
  42. GRB 180914B : continued TSHAO optical observations
  43. GRB 180914A: AstroSat CZTI detection
  44. IPN Triangulation of GRB 180914A (long)
  45. GRB 180914B: VLT/X-shooter spectroscopic redshift
  46. GRB 180914B: MASTER OT automatic dtection
  47. GRB 180914B : TSHAO optical observations
  48. GRB 180914B: Continued RATIR Optical and NIR Observations
  49. GRB 180914B: AGILE/MCAL refined analysis
  50. GRB180914B: Swift UVOT detection of an optical afterglow
  51. Konus-Wind of the very bright GRB 180914B
  52. GRB 180914B: Optical counterpart observation from OAJ
  53. GRB 180914B: RATIR Optical and NIR Observations
  54. GRB 180914B: KAIT Optical Afterglow Candidate
  55. GRB 180914B: Swift-XRT afterglow detection
  56. GRB 180914A: RATIR Optical and NIR Observations
  57. GRB 180914B: Tiled Swift observations
  58. GRB 180914B: Fermi-LAT detection
  59. GRB 180914B: AGILE/GRID detection
  60. GRB 180914A: MASTER automatic inspection
  61. GRB 180914A: Swift-XRT observations
  62. GRB 180914A: Tiled Swift observations
  63. GRB 180914A: Fermi GBM detection
  64. GRB 180914B: AGILE/MCAL detection of a burst
  65. GRB 180914A: Fermi-LAT detection
  66. IceCube-180908A: CALET Gamma-Ray Burst Monitor upper limits
  67. Fermi-LAT Gamma-ray Observations of IceCube-180908A
  68. INTEGRAL observation of IceCube-180908A
  69. Search for counterparts to IceCube-180908A with IceCube
  70. IceCube-180908A: HAWC follow-up
  71. Search for counterpart to IceCube-180908A with ANTARES
  72. GRB 180715A: 15 GHz upper limits from the AMI Short GRB Program
  73. GRB 180718A: 15 GHz upper limits from the AMI Short GRB Program
  74. GRB 180905A: Swift/UVOT Upper Limits
  75. IceCube-180908A - IceCube observation of a high-energy neutrino candidate event
  76. GRB 180905A, Swift-BAT refined analysis
  77. GRB 180905A: RATIR Optical and NIR Observations
  78. GRB 180905A: MITSuME Akeno optical upper limits
  79. GRB 180905A: Swift-XRT refined Analysis
  80. GRB 180904A: BOOTES-2/TELMA early observations
  81. GRB 180905A: BOOTES-3/YA optical observations
  82. GRB 180905A: Enhanced Swift-XRT position
  83. GRB 180904A: AbAO optical upper limit
  84. GRB 180904A: Swift/UVOT Upper Limits
  85. GRB 180904A: RATIR Optical and NIR Observations
  86. GRB 180904A: Swift-BAT refined analysis
  87. Fermi GBM trigger 557852757/180905629 is not a GRB
  88. GRB 180905A: Swift detection of a burst
  89. GRB 180904A: Swift-XRT refined Analysis
  90. GRB 180904A: LT early observations
  91. GRB 180904A: SAO RAS optical observations
  92. GRB 180904A: OSN observations
  93. GRB 180904A: Enhanced Swift-XRT position
  94. GRB 180904A: NOT optical observations, candidate host galaxy
  95. GRB 180904A: Swift detection of a burst
  96. Konus-Wind observation of GRB 180828A
  97. GRB 180829A: Swift-XRT observations
  98. GRB 180828A: AstroSat CZTI detection
  99. GRB 180828A: Swift/UVOT Upper Limits
  100. GRB 180828A: RATIR Optical and NIR Observations

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