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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 181010A: MASTER-Argentina OT detection
  2. GRB 181010A: Swift detection of a burst with an optical counterpart
  3. GRB 181002A: Mondy optical upper limit
  4. GRB 181003A: RATIR Optical and NIR Observations
  5. GRB 181003A: Swift-BAT refined analysis
  6. GRB 181003A: Swift-XRT afterglow detection
  7. GRB 180925A: Astrosat CZTI detection
  8. GRB 181003A: Swift/UVOT Upper Limits
  9. GRB 180930A: TSHAO optical upper limit
  10. GRB 181002A: Swift-XRT refined Analysis
  11. GRB 181003A: LCO Cerro Tololo observations
  12. GRB 181003A: MASTER optical observation
  13. GRB181002A: GOTO optical limits
  14. GRB 181002A: Swift/UVOT Upper Limits
  15. GRB 181003A: Swift-XRT observations
  16. GRB 181003A: Swift detection of a burst
  17. GRB 181002A: Swift-BAT refined analysis
  18. GRB 181002A: MASTER optical observation
  19. GRB 181002A: Enhanced Swift-XRT position
  20. Konus-Wind observation of GRB 180925A
  21. GRB 181002A: Swift detection of a burst
  22. Trigger 864882: Swift detection of Crab in its normal state
  23. GRB 180914B: RTT150 optical observations
  24. GRB 180914B: RTT150 optical observations
  25. GRB 180930A: Swift-BAT refined analysis
  26. GRB 180930A: Swift-XRT refined Analysis
  27. GRB 180930A: NOT optical upper limits
  28. GRB 180930A: Swift/UVOT Upper Limits
  29. GRB 180930A: Enhanced Swift-XRT position
  30. GRB 180930A: KAIT Optical Upper Limit
  31. GRB 180930A: Prompt enhanced Swift-XRT position
  32. GRB 180930A: Swift detection of a burst
  33. INTEGRAL detections of the prompt gamma-ray emission of GRB 180914B
  34. GRB 180924A: Swift/UVOT Upper Limits
  35. GRB 180925A: VLT optical observations
  36. GRB 180925A: Insight-HXMT/HE detection
  37. GRB 180925A: Swift/UVOT Detection
  38. GRB 180925A: Swift-BAT refined analysis
  39. GRB 180925A: Swift-XRT refined Analysis
  40. GRB 180925A: Enhanced Swift-XRT position
  41. GRB 180925A: Prompt enhanced Swift-XRT position
  42. Konus-Wind observation of GRB 180923A
  43. GRB 180925A: Swift detection of a burst
  44. GRB 180924A: MASTER inspection
  45. GRB 180924A: Swift-XRT refined Analysis
  46. GRB 180923B - GBM Correction to GCN 23263
  47. GRB 180924A: Swift-BAT refined analysis
  48. GRB 180923B: Fermi GBM detection
  49. GRB 180924A: Enhanced Swift-XRT position
  50. GRB 180924A: Swift detection of a burst
  51. Swift Trigger 863053 is not an astrophysical event
  52. GRB 180923A: CALET Gamma-Ray Burst Monitor detection
  53. GRB 180923A: MASTER inspection MAXI/GSC error box
  54. GRB 180923A: MAXI/GSC detection
  55. GRB 180914B: OSN Detection and light curve/SED analysis
  56. GRB 180914B: OAJ multi-color follow-up
  57. Konus-Wind observation of GRB 180914A
  58. GRB 180914B: DDOTI/OAN Detection and Confirmation of Fading
  59. GRB 180914B: GOTO optical detection
  60. GRB180914B: Swift UVOT position correction to circ. 23241
  61. GRB 180914B: AstroSat CZTI detection
  62. GRB 180914B : continued TSHAO optical observations
  63. GRB 180914A: AstroSat CZTI detection
  64. IPN Triangulation of GRB 180914A (long)
  65. GRB 180914B: VLT/X-shooter spectroscopic redshift
  66. GRB 180914B: MASTER OT automatic dtection
  67. GRB 180914B : TSHAO optical observations
  68. GRB 180914B: Continued RATIR Optical and NIR Observations
  69. GRB 180914B: AGILE/MCAL refined analysis
  70. GRB180914B: Swift UVOT detection of an optical afterglow
  71. Konus-Wind of the very bright GRB 180914B
  72. GRB 180914B: Optical counterpart observation from OAJ
  73. GRB 180914B: RATIR Optical and NIR Observations
  74. GRB 180914B: KAIT Optical Afterglow Candidate
  75. GRB 180914B: Swift-XRT afterglow detection
  76. GRB 180914A: RATIR Optical and NIR Observations
  77. GRB 180914B: Tiled Swift observations
  78. GRB 180914B: Fermi-LAT detection
  79. GRB 180914B: AGILE/GRID detection
  80. GRB 180914A: MASTER automatic inspection
  81. GRB 180914A: Swift-XRT observations
  82. GRB 180914A: Tiled Swift observations
  83. GRB 180914A: Fermi GBM detection
  84. GRB 180914B: AGILE/MCAL detection of a burst
  85. GRB 180914A: Fermi-LAT detection
  86. IceCube-180908A: CALET Gamma-Ray Burst Monitor upper limits
  87. Fermi-LAT Gamma-ray Observations of IceCube-180908A
  88. INTEGRAL observation of IceCube-180908A
  89. Search for counterparts to IceCube-180908A with IceCube
  90. IceCube-180908A: HAWC follow-up
  91. Search for counterpart to IceCube-180908A with ANTARES
  92. GRB 180715A: 15 GHz upper limits from the AMI Short GRB Program
  93. GRB 180718A: 15 GHz upper limits from the AMI Short GRB Program
  94. GRB 180905A: Swift/UVOT Upper Limits
  95. IceCube-180908A - IceCube observation of a high-energy neutrino candidate event
  96. GRB 180905A, Swift-BAT refined analysis
  97. GRB 180905A: RATIR Optical and NIR Observations
  98. GRB 180905A: MITSuME Akeno optical upper limits
  99. GRB 180905A: Swift-XRT refined Analysis
  100. GRB 180904A: BOOTES-2/TELMA early observations

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