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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"

19549 results found.

  1. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  2. GRB 090820: MASTER-Net optical polarization observations
  3. GRB 090820: Fermi GBM Detection of a bright burst.
  4. GRB 090817: optical upper limit
  5. GRB 090817: Confirmation of the X-ray afterglow
  6. GRB 090815C: Swift refined analysis
  7. GRB 090817: Fermi GBM observation
  8. GRB 090817: Swift/UVOT Upper Limits
  9. GRB 090817: Swift-XRT observations
  10. GRB 090814A: optical observations
  11. GRB 090813: Suzaku WAM observation of the prompt emission
  12. VLA radio non-detection of GRB 090812
  13. GRB 090815B: Fermi GBM detection
  14. GRB 090815: Fermi GBM detection
  15. GRB 090813: CrAO optical obsevations
  16. GRB090814A: NOT optical follow-ups
  17. GRB 090814B: Swift/UVOT Upper Limits
  18. GRB 090814C: Fermi GBM detection
  19. GRB 090814B: Swift-XRT detection of a possible afterglow.
  20. GRB 090814A: Swift/UVOT Observations
  21. GRB 090814A, RIMOTS optical upper limits
  22. GRB 090814A: Swift-BAT refined analysis
  23. GRB090814A: VLT spectroscopy
  24. GRB 090814: Enhanced Swift-XRT position
  25. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  26. GRB 090814: Swift detection of a burst
  27. GRB 090813: Fermi GBM observation
  28. Fermi Gamma-ray Burst Monitor trigger 271446248 is not a GRB
  29. GRB090813: Swift/UVOT upper limits
  30. GRB 090813: Enhanced Swift-XRT position
  31. GRB 090813: P60 Optical Afterglow Confirmation
  32. GRB 090813: Swift detection of a burst
  33. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  34. GRB 090812: RAPTOR detections during the burst
  35. GRB 090812, RIMOTS optical upper limits
  36. GRB090812: Swift/UVOT observations
  37. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  38. GRB 090812: Enhanced Swift-XRT position
  39. GRB 090812: P60 Confirmation of Optical Afterglow
  40. GRB 090812: Swift detection of a burst with an optical counterpart
  41. GRB 090807B: Fermi GBM detection
  42. GRB 090809: Further NOT optical observations
  43. VLA radio upper limit on GRB 090809
  44. GRB 090809: WHT observations
  45. GRB 090809B: Fermi GBM detection
  46. GRB090809: Swift/UVOT observations
  47. GRB 090809: Enhanced Swift-XRT position
  48. GRB 090809: afterglow confirmation at the NOT
  49. GRB 090809: Swift detection of a burst with a possible optical counterpart
  50. GRB 090807: MITSuME optical upper limit
  51. GRB 090807: Swift/UVOT Upper Limits
  52. GRB 090807: Enhanced Swift-XRT position
  53. GRB 090807, RIMOTS optical upper limits
  54. GRB 090807: Swift detection of a burst
  55. GRB 090802: Fermi GBM detection
  56. GRB 090726: optical observation
  57. Swift trigger 358760 is probably a noise event
  58. GRB 090727: GRT Optical Observation
  59. GRB 090726: GRT Optical Observation
  60. GRB 090727: Swift/UVOT Upper Limits
  61. GRB 090728: Swift/UVOT Upper Limits
  62. GRB 090728: Enhanced Swift-XRT position
  63. GRB 090728, RIMOTS optical upper limits
  64. GRB 090728: Swift detection of a burst
  65. GRB 090727: Enhanced Swift-XRT position
  66. GRB 090715B: Late-time Lick 3m observations
  67. GRB 090727: Swift detection of a burst
  68. GRB090726: Swift/UVOT observations
  69. GRB 090711: Fermi GBM detection
  70. GRB 090726: Enhanced Swift-XRT position
  71. GRB 090726: optical transient candidate
  72. GRB 090726: Swift/UVOT Finding Chart Observation
  73. Konus-Wind observations of bright hard GRB 090720B
  74. GRB 090720B: Fermi GBM detection
  75. Swift XRT and UVOT refned analysis of GRB 090720
  76. GRB 090709A: Swift XRT Timing Analysis
  77. GRB 090715B: VLA radio detection
  78. GRB 090720 Source found in ground processing of Swift-BAT data
  79. GRB 090717B: Fermi GBM detection
  80. GRB 090717: Fermi GBM detection
  81. GRB 090719: Fermi GBM detection
  82. GRB 090718B: Fermi GBM detection
  83. GRB 090720: Fermi GBM detection
  84. GRB 090715B: further NOT optical observations
  85. GRB 090709A - CARMA mm Observations
  86. GRB 090715A: VLA observations
  87. GRB 090715B: Swift/UVOT followup observations
  88. GRB 090715B: Enhanced Swift-XRT position
  89. GRB 090715B: Observation of the optical afterglow
  90. GRB 090715B: NOT optical observations
  91. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  92. GRB 090712: Fermi GBM observation
  93. GRB 090713: Fermi GBM detection
  94. VLA radio observations of GRB 090709A
  95. GRB 090621B: MTM-500 optical observations
  96. GRB 090709A: deep optical observation with the 10.4m GTC
  97. GRB 090709A: Swift UVOT upper limits
  98. GRB 090709A: WHT LIRIS observations
  99. GRB 090709B: Fermi GBM detection
  100. GRB 090709A: confirmation of the periodicity in the SPI-ACS data

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