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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. GRB090201: Swift UVOT upper limits
  2. GRB 090201: object inside the enhanced XRT error circle
  3. GRB 090201: Enhanced Swift-XRT position
  4. GRB 090201: VLT NIR observations
  5. GRB 090201: Swift-BAT refined analysis
  6. GRB 090201: VLT afterglow candidate
  7. GRB 090201: Swift-XRT detection of the possible X-ray afterglow
  8. GRB090113: MAGIC telescope GeV observation
  9. GRB 090201: ROTSE-III Optical Limits
  10. GRB 090201: Swift detection of a burst
  11. GRB 090126A: Swift/UVOT Upper Limits
  12. Konus-Wind observation of bright burst from AXP/SGR 1E1547.0-5408 on January 29
  13. GRB 090129: Swift-BAT refined analysis
  14. GRB 090129: Swift detection of a burst
  15. IBAS Alert N. 5442 is not a GRB
  16. Suzaku ToO Observation of AXP 1E 1547.0-5408
  17. Konus-Wind observation of AXP/SGR 1E1547.0-5408 bursting activity
  18. AXP 1E1547.0-5408: RHESSI observations up to 400 keV
  19. GRB 090102: HST observations and host galaxy
  20. GRB 090126C: Fermi GBM detection
  21. GRB 090126A: Swift-XRT Refined Analysis
  22. GRB 090126B: Fermi GBM detection
  23. GRB 090126: SuperAGILE Localization of a Long GRB
  24. Konus-Wind detection of very bright SGR-like burst on January 25, 2009
  25. GRB 090118: no afterglow candidate
  26. GRB 090123: GROND detection
  27. 1E1547.0-5408: Swift detection of dust halo
  28. GRB 090123: Swift XRT refined analysis
  29. GRB 090123: Swift/UVOT Observations
  30. AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
  31. GRB 090123: Swift-BAT refined analysis
  32. GRB090123: Enhanced Swift-XRT position
  33. GRB 090123: Swift detection of a burst
  34. AXP 1E1547.0-5408: long bursts with INTEGRAL SPI-ACS
  35. GRB 090118: Swift XRT Observations - Confirmation of an Afterglow
  36. Swift-BAT trigger 340734 is not a GRB
  37. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  38. AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
  39. GRB 090117C: Suzaku WAM observation of the prompt emission
  40. AXP 1E1547.0-5408: Fermi GBM observations
  41. Trigger 340734: Swift detection of a possible short burst
  42. AXP 1E1547.0-5408 activity with SGR bursts
  43. GRB 090118: Subaru NIR Observation
  44. GRB 090118: KPNO 4m 2nd Epoch Observations
  45. GRB 090118 (BATSS): GRT Optical Observation
  46. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  47. GRB 090118: Swift-XRT observations
  48. GRB090118 Swift/UVOT upper limits
  49. GRB 090118: GROND Upper Limits
  50. GRB 090118: Possible burst detection from Swift-BAT slew data
  51. GRB 090117B : Fermi GBM detection
  52. GRB 090117: confirmation of the X-ray afterglow
  53. GRB 090117C - Fermi GRB Detection
  54. GRB 090117 - Fermi GBM Observations
  55. GRB 090117: GROND Upper Limits
  56. GRB090117 Swift/UVOT upper limits
  57. GRB090117: Swift-XRT detection of a possible candidate afterglow
  58. GRB 090117 - SuperAGILE Localization of a long GRB
  59. GRB090102: MAGIC telescope GeV observation
  60. GRB 090112B: Suzaku WAM observation of the prompt emission
  61. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  62. GRB 090113: Swift UVOT upper limits
  63. GRB 090113: GROND Upper Limits
  64. GRB 090113: Swift-XRT refined analysis
  65. GRB 090113: Observations from NOT
  66. GRB 090113: Enhanced Swift-XRT position
  67. GRB 090113: Swift-BAT refined analysis
  68. GRB 090113: ROTSE-III Optical Limits
  69. GRB090113: XRT position
  70. GRB 090112B: Fermi GBM Detection
  71. GRB 090113: Swift detection of a burst
  72. GRB 090112: Fermi GBM detection
  73. GRB 090109: Fermi GBM detection
  74. GRB 090108B: Fermi GBM detection
  75. GRB 090111, Swift-BAT refined analysis
  76. GRB 090111: Swift UVOT Upper Limits
  77. GRB 090108: Fermi GBM Detection
  78. GRB 090111: Swift-XRT refined analysis
  79. GRB 090111: Enhanced Swift-XRT position
  80. GRB 090111: Swift detection of a burst
  81. GRB 090107B: Suzaku WAM observation of the prompt emission
  82. GRB090107B: Fermi GBM Detection
  83. GRB 090102: WSRT Radio Observations
  84. GRB 090107B: Swift XRT afterglow confirmation
  85. GRB 090107B: Swift/UVOT Observations
  86. GRB 090107B: Swift-XRT detection of possible afterglow
  87. GRB 090107B optical observations
  88. GRB 090107B: ROTSE-III Optical Limits
  89. GRB 090107B: a long GRB localized by INTEGRAL
  90. Fermi/GBM detection of GRB 081226A
  91. Fermi/GBM detection of GRB 081225
  92. GRB 090107: Swift-BAT refined analysis
  93. GRB 090107: Swift detection of a burst
  94. GRB 081231: Fermi GBM Detection
  95. GRB 090102: optical decay
  96. VLA radio upper limit on GRB 090102
  97. GRB 090102: GRT Optical Observation
  98. Swift triggered on the HMXB 1A 1118-61
  99. Konus-Wind observation of GRB 090102
  100. GRB 081229: Fermi GBM detection

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