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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 090118: no afterglow candidate
  2. GRB 090123: GROND detection
  3. 1E1547.0-5408: Swift detection of dust halo
  4. GRB 090123: Swift XRT refined analysis
  5. GRB 090123: Swift/UVOT Observations
  6. AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
  7. GRB 090123: Swift-BAT refined analysis
  8. GRB090123: Enhanced Swift-XRT position
  9. GRB 090123: Swift detection of a burst
  10. AXP 1E1547.0-5408: long bursts with INTEGRAL SPI-ACS
  11. GRB 090118: Swift XRT Observations - Confirmation of an Afterglow
  12. Swift-BAT trigger 340734 is not a GRB
  13. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  14. AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
  15. GRB 090117C: Suzaku WAM observation of the prompt emission
  16. AXP 1E1547.0-5408: Fermi GBM observations
  17. Trigger 340734: Swift detection of a possible short burst
  18. AXP 1E1547.0-5408 activity with SGR bursts
  19. GRB 090118: Subaru NIR Observation
  20. GRB 090118: KPNO 4m 2nd Epoch Observations
  21. GRB 090118 (BATSS): GRT Optical Observation
  22. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  23. GRB 090118: Swift-XRT observations
  24. GRB090118 Swift/UVOT upper limits
  25. GRB 090118: GROND Upper Limits
  26. GRB 090118: Possible burst detection from Swift-BAT slew data
  27. GRB 090117B : Fermi GBM detection
  28. GRB 090117: confirmation of the X-ray afterglow
  29. GRB 090117C - Fermi GRB Detection
  30. GRB 090117 - Fermi GBM Observations
  31. GRB 090117: GROND Upper Limits
  32. GRB090117 Swift/UVOT upper limits
  33. GRB090117: Swift-XRT detection of a possible candidate afterglow
  34. GRB 090117 - SuperAGILE Localization of a long GRB
  35. GRB090102: MAGIC telescope GeV observation
  36. GRB 090112B: Suzaku WAM observation of the prompt emission
  37. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  38. GRB 090113: Swift UVOT upper limits
  39. GRB 090113: GROND Upper Limits
  40. GRB 090113: Swift-XRT refined analysis
  41. GRB 090113: Observations from NOT
  42. GRB 090113: Enhanced Swift-XRT position
  43. GRB 090113: Swift-BAT refined analysis
  44. GRB 090113: ROTSE-III Optical Limits
  45. GRB090113: XRT position
  46. GRB 090112B: Fermi GBM Detection
  47. GRB 090113: Swift detection of a burst
  48. GRB 090112: Fermi GBM detection
  49. GRB 090109: Fermi GBM detection
  50. GRB 090108B: Fermi GBM detection
  51. GRB 090111, Swift-BAT refined analysis
  52. GRB 090111: Swift UVOT Upper Limits
  53. GRB 090108: Fermi GBM Detection
  54. GRB 090111: Swift-XRT refined analysis
  55. GRB 090111: Enhanced Swift-XRT position
  56. GRB 090111: Swift detection of a burst
  57. GRB 090107B: Suzaku WAM observation of the prompt emission
  58. GRB090107B: Fermi GBM Detection
  59. GRB 090102: WSRT Radio Observations
  60. GRB 090107B: Swift XRT afterglow confirmation
  61. GRB 090107B: Swift/UVOT Observations
  62. GRB 090107B: Swift-XRT detection of possible afterglow
  63. GRB 090107B optical observations
  64. GRB 090107B: ROTSE-III Optical Limits
  65. GRB 090107B: a long GRB localized by INTEGRAL
  66. Fermi/GBM detection of GRB 081226A
  67. Fermi/GBM detection of GRB 081225
  68. GRB 090107: Swift-BAT refined analysis
  69. GRB 090107: Swift detection of a burst
  70. GRB 081231: Fermi GBM Detection
  71. GRB 090102: optical decay
  72. VLA radio upper limit on GRB 090102
  73. GRB 090102: GRT Optical Observation
  74. Swift triggered on the HMXB 1A 1118-61
  75. Konus-Wind observation of GRB 090102
  76. GRB 081229: Fermi GBM detection
  77. GRB 090102: Hobby-Eberly Telescope Spectroscopy
  78. GRB 090102: P60 Imaging and P200 Spectroscopy
  79. GRB 090102 Observations from IAC80
  80. GRB 090102: GROND observations of the optical afterglow
  81. Swift UVOT observations of GRB 090102
  82. GRB 090102: Swift-BAT refined analysis
  83. GRB 090102: Swift burst of interest
  84. GRB 090102: Swift XRT refined analysis
  85. GRB 090102: NOT redshift
  86. GRB 090102: Enhanced Swift-XRT position
  87. GRB 090102: TAROT Calern observatory optical light curve
  88. GRB 090102: REM observations of a bright afterglow
  89. GRB 090102: Swift detection of a burst with an optical counterpart
  90. GRB 090102: TAROT Calern observatory optical observations
  91. GRB 081230: GROND confirmation of the afterglow
  92. GRB 081230, Swift-BAT refined analysis
  93. GRB081230: Swift-XRT refined analysis
  94. GRB 081230 Swift/UVOT Observations
  95. GRB 081230: Enhanced Swift-XRT position
  96. GRB 081230: Swift/UVOT Detection of an Optical Afterglow
  97. GRB 081230: ROTSE-III Detection of Optical Counterpart
  98. GRB 081230: Swift detection of a burst
  99. GRB 081228: GROND confirmation of the optical/NIR afterglow
  100. GRB 081226B: Fermi GBM observation

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