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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 090202: Fermi GBM detection
  2. GRB 090131: Fermi GBM detection
  3. GRB 090201: Swift-XRT refined analysis
  4. GRB090201: Swift UVOT upper limits
  5. GRB 090201: object inside the enhanced XRT error circle
  6. GRB 090201: Enhanced Swift-XRT position
  7. GRB 090201: VLT NIR observations
  8. GRB 090201: Swift-BAT refined analysis
  9. GRB 090201: VLT afterglow candidate
  10. GRB 090201: Swift-XRT detection of the possible X-ray afterglow
  11. GRB090113: MAGIC telescope GeV observation
  12. GRB 090201: ROTSE-III Optical Limits
  13. GRB 090201: Swift detection of a burst
  14. GRB 090126A: Swift/UVOT Upper Limits
  15. Konus-Wind observation of bright burst from AXP/SGR 1E1547.0-5408 on January 29
  16. GRB 090129: Swift-BAT refined analysis
  17. GRB 090129: Swift detection of a burst
  18. IBAS Alert N. 5442 is not a GRB
  19. Suzaku ToO Observation of AXP 1E 1547.0-5408
  20. Konus-Wind observation of AXP/SGR 1E1547.0-5408 bursting activity
  21. AXP 1E1547.0-5408: RHESSI observations up to 400 keV
  22. GRB 090102: HST observations and host galaxy
  23. GRB 090126C: Fermi GBM detection
  24. GRB 090126A: Swift-XRT Refined Analysis
  25. GRB 090126B: Fermi GBM detection
  26. GRB 090126: SuperAGILE Localization of a Long GRB
  27. Konus-Wind detection of very bright SGR-like burst on January 25, 2009
  28. GRB 090118: no afterglow candidate
  29. GRB 090123: GROND detection
  30. 1E1547.0-5408: Swift detection of dust halo
  31. GRB 090123: Swift XRT refined analysis
  32. GRB 090123: Swift/UVOT Observations
  33. AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
  34. GRB 090123: Swift-BAT refined analysis
  35. GRB090123: Enhanced Swift-XRT position
  36. GRB 090123: Swift detection of a burst
  37. AXP 1E1547.0-5408: long bursts with INTEGRAL SPI-ACS
  38. GRB 090118: Swift XRT Observations - Confirmation of an Afterglow
  39. Swift-BAT trigger 340734 is not a GRB
  40. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  41. AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
  42. GRB 090117C: Suzaku WAM observation of the prompt emission
  43. AXP 1E1547.0-5408: Fermi GBM observations
  44. Trigger 340734: Swift detection of a possible short burst
  45. AXP 1E1547.0-5408 activity with SGR bursts
  46. GRB 090118: Subaru NIR Observation
  47. GRB 090118: KPNO 4m 2nd Epoch Observations
  48. GRB 090118 (BATSS): GRT Optical Observation
  49. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  50. GRB 090118: Swift-XRT observations
  51. GRB090118 Swift/UVOT upper limits
  52. GRB 090118: GROND Upper Limits
  53. GRB 090118: Possible burst detection from Swift-BAT slew data
  54. GRB 090117B : Fermi GBM detection
  55. GRB 090117: confirmation of the X-ray afterglow
  56. GRB 090117C - Fermi GRB Detection
  57. GRB 090117 - Fermi GBM Observations
  58. GRB 090117: GROND Upper Limits
  59. GRB090117 Swift/UVOT upper limits
  60. GRB090117: Swift-XRT detection of a possible candidate afterglow
  61. GRB 090117 - SuperAGILE Localization of a long GRB
  62. GRB090102: MAGIC telescope GeV observation
  63. GRB 090112B: Suzaku WAM observation of the prompt emission
  64. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  65. GRB 090113: Swift UVOT upper limits
  66. GRB 090113: GROND Upper Limits
  67. GRB 090113: Swift-XRT refined analysis
  68. GRB 090113: Observations from NOT
  69. GRB 090113: Enhanced Swift-XRT position
  70. GRB 090113: Swift-BAT refined analysis
  71. GRB 090113: ROTSE-III Optical Limits
  72. GRB090113: XRT position
  73. GRB 090112B: Fermi GBM Detection
  74. GRB 090113: Swift detection of a burst
  75. GRB 090112: Fermi GBM detection
  76. GRB 090109: Fermi GBM detection
  77. GRB 090108B: Fermi GBM detection
  78. GRB 090111, Swift-BAT refined analysis
  79. GRB 090111: Swift UVOT Upper Limits
  80. GRB 090108: Fermi GBM Detection
  81. GRB 090111: Swift-XRT refined analysis
  82. GRB 090111: Enhanced Swift-XRT position
  83. GRB 090111: Swift detection of a burst
  84. GRB 090107B: Suzaku WAM observation of the prompt emission
  85. GRB090107B: Fermi GBM Detection
  86. GRB 090102: WSRT Radio Observations
  87. GRB 090107B: Swift XRT afterglow confirmation
  88. GRB 090107B: Swift/UVOT Observations
  89. GRB 090107B: Swift-XRT detection of possible afterglow
  90. GRB 090107B optical observations
  91. GRB 090107B: ROTSE-III Optical Limits
  92. GRB 090107B: a long GRB localized by INTEGRAL
  93. Fermi/GBM detection of GRB 081226A
  94. Fermi/GBM detection of GRB 081225
  95. GRB 090107: Swift-BAT refined analysis
  96. GRB 090107: Swift detection of a burst
  97. GRB 081231: Fermi GBM Detection
  98. GRB 090102: optical decay
  99. VLA radio upper limit on GRB 090102
  100. GRB 090102: GRT Optical Observation

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