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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. Swift-BAT trigger 358760 is most likely not a GRB
  2. Swift trigger 358760 is probably a noise event
  3. GRB 090717A: Suzaku WAM observation of the prompt emission
  4. GRB 090709A : Quick look analysis of the Suzaku observation
  5. GRB 090728: Swift-BAT refined analysis
  6. GRB 090727: GRT Optical Observation
  7. GRB 090728: Swift XRT refined analysis
  8. GRB 090727: optical observations
  9. GRB 090726: GRT Optical Observation
  10. GRB 090727: Swift/UVOT Upper Limits
  11. GRB 090728: Swift/UVOT Upper Limits
  12. GRB 090728: Enhanced Swift-XRT position
  13. GRB 090727: I-band observations from 1.23m CAHA
  14. GRB 090728, RIMOTS optical upper limits
  15. GRB 090728A: Faulkes Telescope North Optical Afterglow Candidate
  16. GRB 090728: Swift detection of a burst
  17. GRB 090727: Swift-BAT refined analysis
  18. GRB 090727: Swift-XRT refined analysis
  19. GRB 090727: Liverpool Telescope Afterglow Confirmation and Optical Flare
  20. GRB 090727: Enhanced Swift-XRT position
  21. GRB 090715B: Late-time Lick 3m observations
  22. GRB 090727: Liverpool Telescope possible OT candidate
  23. GRB 090727: Swift detection of a burst
  24. GRB090726: Swift/UVOT observations
  25. GRB 090726, Swift-BAT refined analysis
  26. GRB 090726: Afterglow candidate photometryfrom Crni Vrh
  27. GRB 090726: D50 optical observations
  28. GRB 090711: Fermi GBM detection
  29. GRB090726: 6-meter telescope redshift
  30. GRB 090726: Swift-XRT Team refined analysis
  31. GRB 090726: Enhanced Swift-XRT position
  32. GRB 090726: optical transient candidate
  33. GRB 090726: Swift/UVOT Finding Chart Observation
  34. GRB 090726: Swift-XRT position of probable counterpart
  35. GRB 090726: Swift detection of a burst
  36. Swift Trigger 358354 is not a GRB
  37. Konus-Wind and Konus-RF observations of GRB 090719
  38. Konus-RF and Konus-Wind observations of GRB 090718B
  39. Fermi Gamma-ray Burst Monitor triggers 269935914 through 270021937 are not GRBs
  40. Konus-Wind observations of bright hard GRB 090720B
  41. IPN Triangulation of bright GRB 090720B
  42. GRB 090720: Gemini-North Imaging and Optical Afterglow
  43. GRB 090720B: Fermi GBM detection
  44. Swift XRT and UVOT refned analysis of GRB 090720
  45. GRB 090709A: Swift XRT Timing Analysis
  46. GRB 090715B: VLA radio detection
  47. GRB 090720 Source found in ground processing of Swift-BAT data
  48. GRB 090717B: Fermi GBM detection
  49. GRB 090717: Fermi GBM detection
  50. GRB 090719: Fermi GBM detection
  51. GRB 090718B: Fermi GBM detection
  52. GRB 090718: Fermi GBM detection
  53. GRB 090720: Fermi GBM detection
  54. GRB 090715B: further NOT optical observations
  55. GRB 090715A: Suzaku WAM observation of the prompt emission
  56. GRB 090709A - CARMA mm Observations
  57. GRB 090715B: Lick observations
  58. GRB 090715A: VLA observations
  59. Konus-Wind observations of short/hard GRB 090715A
  60. GRB 090715B: MASTER optical limit
  61. GRB 090715A: Swift-BAT refined analysis
  62. Konus-Wind and Konus-RF observations of GRB 090715B
  63. GRB 090715B: Swift/UVOT followup observations
  64. GRB 090715B: break in the optical afterglow decay
  65. GRB 090715B: Enhanced Swift-XRT position
  66. GRB 090715B: Observation of the optical afterglow
  67. GRB 090715B: Swift XRT Refined Analysis
  68. GRB090715B: WHT redshift
  69. GRB 090715B: Swift-BAT refined analysis
  70. GRB 090715B: NOT optical observations
  71. GRB 090715B - Liverpool Telescope Optical Afterglow Candidate
  72. Swift problem fixed
  73. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  74. GRB 090715A: ROTSE-III Optical Limits
  75. GRB 090715: Swift detection of a short hard burst
  76. Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite
  77. Swift satellite anomaly
  78. GRB090713 optical limit by "Pi of the Sky"
  79. GRB 090712: Fermi GBM observation
  80. GRB 090713: Fermi GBM detection
  81. GRB 090712: Swift-BAT refined analysis
  82. GRB 090712: Swift detection of a burst
  83. GRB 090709A: Xinglong TNT optical upper limit
  84. VLA radio observations of GRB 090709A
  85. GRB 090621B: MTM-500 optical observations
  86. GRB 090709A: deep optical observation with the 10.4m GTC
  87. GRB090709A : WSRT Radio observation
  88. GRB 090709A: Suzaku WAM observation of the prompt emission
  89. GRB 090709A: Swift UVOT upper limits
  90. GRB 090709A: WHT LIRIS observations
  91. GRB 090709B: Fermi GBM detection
  92. GRB 090709A: confirmation of the periodicity in the SPI-ACS data
  93. GRB 090709A: evidence for a very red afterglow at low z
  94. Konus-Wind and Konus-RF observations of GRB 090709A
  95. GRB 090709A: P60 Observations
  96. GRB 090709A: Quasiperiodic variations in the BAT light curve
  97. GRB 090709A: NOT optical observations
  98. GRB 090709A: RAPTOR Limits During Gamma-Ray Emission
  99. GRB 090709A: Swift XRT Refined Analysis
  100. GRB 090709B, Swift-BAT refined analysis

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