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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 090126C: Fermi GBM detection
  2. GRB 090126A: Swift-XRT Refined Analysis
  3. GRB 090126B: Fermi GBM detection
  4. GRB 090126: SuperAGILE Localization of a Long GRB
  5. Konus-Wind detection of very bright SGR-like burst on January 25, 2009
  6. GRB 090118: no afterglow candidate
  7. GRB 090123: GROND detection
  8. 1E1547.0-5408: Swift detection of dust halo
  9. GRB 090123: Swift XRT refined analysis
  10. GRB 090123: Swift/UVOT Observations
  11. AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
  12. GRB 090123: Swift-BAT refined analysis
  13. GRB090123: Enhanced Swift-XRT position
  14. GRB 090123: Swift detection of a burst
  15. AXP 1E1547.0-5408: long bursts with INTEGRAL SPI-ACS
  16. GRB 090118: Swift XRT Observations - Confirmation of an Afterglow
  17. Swift-BAT trigger 340734 is not a GRB
  18. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  19. AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
  20. GRB 090117C: Suzaku WAM observation of the prompt emission
  21. AXP 1E1547.0-5408: Fermi GBM observations
  22. Trigger 340734: Swift detection of a possible short burst
  23. AXP 1E1547.0-5408 activity with SGR bursts
  24. GRB 090118: Subaru NIR Observation
  25. GRB 090118: KPNO 4m 2nd Epoch Observations
  26. GRB 090118 (BATSS): GRT Optical Observation
  27. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  28. GRB 090118: Swift-XRT observations
  29. GRB090118 Swift/UVOT upper limits
  30. GRB 090118: GROND Upper Limits
  31. GRB 090118: Possible burst detection from Swift-BAT slew data
  32. GRB 090117B : Fermi GBM detection
  33. GRB 090117: confirmation of the X-ray afterglow
  34. GRB 090117C - Fermi GRB Detection
  35. GRB 090117 - Fermi GBM Observations
  36. GRB 090117: GROND Upper Limits
  37. GRB090117 Swift/UVOT upper limits
  38. GRB090117: Swift-XRT detection of a possible candidate afterglow
  39. GRB 090117 - SuperAGILE Localization of a long GRB
  40. GRB090102: MAGIC telescope GeV observation
  41. GRB 090112B: Suzaku WAM observation of the prompt emission
  42. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  43. GRB 090113: Swift UVOT upper limits
  44. GRB 090113: GROND Upper Limits
  45. GRB 090113: Swift-XRT refined analysis
  46. GRB 090113: Observations from NOT
  47. GRB 090113: Enhanced Swift-XRT position
  48. GRB 090113: Swift-BAT refined analysis
  49. GRB 090113: ROTSE-III Optical Limits
  50. GRB090113: XRT position
  51. GRB 090112B: Fermi GBM Detection
  52. GRB 090113: Swift detection of a burst
  53. GRB 090112: Fermi GBM detection
  54. GRB 090109: Fermi GBM detection
  55. GRB 090108B: Fermi GBM detection
  56. GRB 090111, Swift-BAT refined analysis
  57. GRB 090111: Swift UVOT Upper Limits
  58. GRB 090108: Fermi GBM Detection
  59. GRB 090111: Swift-XRT refined analysis
  60. GRB 090111: Enhanced Swift-XRT position
  61. GRB 090111: Swift detection of a burst
  62. GRB 090107B: Suzaku WAM observation of the prompt emission
  63. GRB090107B: Fermi GBM Detection
  64. GRB 090102: WSRT Radio Observations
  65. GRB 090107B: Swift XRT afterglow confirmation
  66. GRB 090107B: Swift/UVOT Observations
  67. GRB 090107B: Swift-XRT detection of possible afterglow
  68. GRB 090107B optical observations
  69. GRB 090107B: ROTSE-III Optical Limits
  70. GRB 090107B: a long GRB localized by INTEGRAL
  71. Fermi/GBM detection of GRB 081226A
  72. Fermi/GBM detection of GRB 081225
  73. GRB 090107: Swift-BAT refined analysis
  74. GRB 090107: Swift detection of a burst
  75. GRB 081231: Fermi GBM Detection
  76. GRB 090102: optical decay
  77. VLA radio upper limit on GRB 090102
  78. GRB 090102: GRT Optical Observation
  79. Swift triggered on the HMXB 1A 1118-61
  80. Konus-Wind observation of GRB 090102
  81. GRB 081229: Fermi GBM detection
  82. GRB 090102: Hobby-Eberly Telescope Spectroscopy
  83. GRB 090102: P60 Imaging and P200 Spectroscopy
  84. GRB 090102 Observations from IAC80
  85. GRB 090102: GROND observations of the optical afterglow
  86. Swift UVOT observations of GRB 090102
  87. GRB 090102: Swift-BAT refined analysis
  88. GRB 090102: Swift burst of interest
  89. GRB 090102: Swift XRT refined analysis
  90. GRB 090102: NOT redshift
  91. GRB 090102: Enhanced Swift-XRT position
  92. GRB 090102: TAROT Calern observatory optical light curve
  93. GRB 090102: REM observations of a bright afterglow
  94. GRB 090102: Swift detection of a burst with an optical counterpart
  95. GRB 090102: TAROT Calern observatory optical observations
  96. GRB 081230: GROND confirmation of the afterglow
  97. GRB 081230, Swift-BAT refined analysis
  98. GRB081230: Swift-XRT refined analysis
  99. GRB 081230 Swift/UVOT Observations
  100. GRB 081230: Enhanced Swift-XRT position

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