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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"

19866 results found.

  1. Swift Trigger 361477, called GRB090831B, is probably not real.
  2. GRB090831C: Swift/UVOT upper limits
  3. GRB 090831B: MITSuME optical upper limits
  4. GRB 090831C: Enhanced Swift-XRT position
  5. GRB 090831C: Swift detection of a burst
  6. GRB 090831B, RIMOTS optical upper limits
  7. GRB 090831B: Swift detection of a possible burst
  8. GRB090829: Fermi GBM Detection
  9. GRB 090827: Swift XRT and UVOT observations
  10. GRB 090827 Burst discovered in BAT ground analysis
  11. GRB 090817 - TLS Observations
  12. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  13. GRB 090823 Correction to BAT position
  14. GRB 090817: No host galaxy, no supernova
  15. GRB 090823 Long burst with IPN triangulation and BAT position
  16. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  17. GRB 090820: MASTER-Net optical polarization observations
  18. GRB 090817: optical upper limit
  19. GRB 090817: Confirmation of the X-ray afterglow
  20. GRB 090817: Swift/UVOT Upper Limits
  21. GRB 090817: Swift-XRT observations
  22. GRB 090814A: optical observations
  23. VLA radio non-detection of GRB 090812
  24. GRB 090813: CrAO optical obsevations
  25. GRB090814A: NOT optical follow-ups
  26. GRB 090814B: Swift/UVOT Upper Limits
  27. GRB 090814B: Swift-XRT detection of a possible afterglow.
  28. GRB 090814A: Swift/UVOT Observations
  29. GRB 090814A, RIMOTS optical upper limits
  30. GRB090814A: VLT spectroscopy
  31. GRB 090814: Enhanced Swift-XRT position
  32. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  33. GRB 090814: Swift detection of a burst
  34. GRB090813: Swift/UVOT upper limits
  35. GRB 090813: Enhanced Swift-XRT position
  36. GRB 090813: P60 Optical Afterglow Confirmation
  37. GRB 090813: Swift detection of a burst
  38. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  39. GRB 090812: RAPTOR detections during the burst
  40. GRB 090812, RIMOTS optical upper limits
  41. GRB 090812 Swift-BAT Refined Analysis
  42. GRB090812: Swift/UVOT observations
  43. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  44. GRB 090812: Enhanced Swift-XRT position
  45. GRB 090812: P60 Confirmation of Optical Afterglow
  46. GRB 090812: Swift detection of a burst with an optical counterpart
  47. GRB 090809: Further NOT optical observations
  48. VLA radio upper limit on GRB 090809
  49. GRB 090621B: MAGIC telescope GeV observation
  50. GRB 090809: WHT observations
  51. GRB090809: Swift/UVOT observations
  52. GRB 090809: Enhanced Swift-XRT position
  53. GRB 090809: afterglow confirmation at the NOT
  54. GRB 090809: Swift detection of a burst with a possible optical counterpart
  55. GRB 090807: MITSuME optical upper limit
  56. GRB 090807: Swift/UVOT Upper Limits
  57. GRB 090807: Enhanced Swift-XRT position
  58. GRB 090807, RIMOTS optical upper limits
  59. GRB 090807: Swift detection of a burst
  60. GRB 090726: optical observation
  61. Swift trigger 358760 is probably a noise event
  62. GRB 090727: GRT Optical Observation
  63. GRB 090728: Swift XRT refined analysis
  64. GRB 090726: GRT Optical Observation
  65. GRB 090727: Swift/UVOT Upper Limits
  66. GRB 090728: Swift/UVOT Upper Limits
  67. GRB 090728: Enhanced Swift-XRT position
  68. GRB 090728, RIMOTS optical upper limits
  69. GRB 090728: Swift detection of a burst
  70. GRB 090727: Enhanced Swift-XRT position
  71. GRB 090715B: Late-time Lick 3m observations
  72. GRB 090727: Swift detection of a burst
  73. GRB090726: Swift/UVOT observations
  74. GRB 090726: Enhanced Swift-XRT position
  75. GRB 090726: optical transient candidate
  76. Swift XRT and UVOT refned analysis of GRB 090720
  77. GRB 090715B: VLA radio detection
  78. GRB 090720 Source found in ground processing of Swift-BAT data
  79. GRB 090715B: further NOT optical observations
  80. GRB 090709A - CARMA mm Observations
  81. GRB 090715A: VLA observations
  82. GRB 090715B: Swift/UVOT followup observations
  83. GRB 090715B: Enhanced Swift-XRT position
  84. GRB 090715B: Observation of the optical afterglow
  85. GRB 090715B: NOT optical observations
  86. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  87. Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite
  88. VLA radio observations of GRB 090709A
  89. GRB 090621B: MTM-500 optical observations
  90. GRB 090709A: deep optical observation with the 10.4m GTC
  91. GRB 090709A: Swift UVOT upper limits
  92. GRB 090709A: WHT LIRIS observations
  93. GRB 090709A: P60 Observations
  94. GRB 090709A: NOT optical observations
  95. GRB 090709A: RAPTOR Limits During Gamma-Ray Emission
  96. GRB090709A: High Energy BAT/XRT Analysis Suggests Low to Moderate Redshift
  97. GRB 090709A: Wyoming Infrared Observatory NIR upper limits
  98. GRB 090709A, RIMOTS optical upper limits
  99. GRB 090709A: Enhanced Swift-XRT position
  100. GRB 090709A: Subaru NIR observation

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