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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 090205: Swift/UVOT Upper Limits
  2. GRB 090205: VLT refined redshift
  3. GRB 090205: Swift-XRT refined analysis
  4. GRB 090205: Swift burst of interest
  5. GRB 090205: VLT spectroscopic redshift
  6. GRB 090205: GROND observations and photometric redshift estimate
  7. GRB 090205: VLT candidate afterglow
  8. GRB 090205: Swift-BAT refined analysis
  9. GRB 090205: Enhanced Swift-XRT position
  10. GRB 090205: Swift detection of a burst
  11. GRB 080319B: IceCube upper limit on high-energy neutrino flux
  12. GRB 090131: Suzaku WAM observation of the prompt emission
  13. ICSP VLF observation of the signatures of SGR/AXP 1E1547.0-5408 bursts
  14. GRB 090126A: Swift-XRT afterglow confirmation
  15. Fermi Gamma-ray Burst Monitor trigger 255342766 is not a GRB
  16. Konus-Wind observation of GRB 090201
  17. GRB 090202: Fermi GBM detection
  18. GRB 090131: Fermi GBM detection
  19. GRB 090201: Swift-XRT refined analysis
  20. GRB090201: Swift UVOT upper limits
  21. GRB 090201: object inside the enhanced XRT error circle
  22. GRB 090201: Enhanced Swift-XRT position
  23. GRB 090201: VLT NIR observations
  24. GRB 090201: Swift-BAT refined analysis
  25. GRB 090201: VLT afterglow candidate
  26. GRB 090201: Swift-XRT detection of the possible X-ray afterglow
  27. GRB090113: MAGIC telescope GeV observation
  28. GRB 090201: ROTSE-III Optical Limits
  29. GRB 090201: Swift detection of a burst
  30. GRB 090126A: Swift/UVOT Upper Limits
  31. Konus-Wind observation of bright burst from AXP/SGR 1E1547.0-5408 on January 29
  32. GRB 090129: Swift-BAT refined analysis
  33. GRB 090129: Swift detection of a burst
  34. IBAS Alert N. 5442 is not a GRB
  35. Suzaku ToO Observation of AXP 1E 1547.0-5408
  36. Konus-Wind observation of AXP/SGR 1E1547.0-5408 bursting activity
  37. AXP 1E1547.0-5408: RHESSI observations up to 400 keV
  38. GRB 090102: HST observations and host galaxy
  39. GRB 090126C: Fermi GBM detection
  40. GRB 090126A: Swift-XRT Refined Analysis
  41. GRB 090126B: Fermi GBM detection
  42. GRB 090126: SuperAGILE Localization of a Long GRB
  43. Konus-Wind detection of very bright SGR-like burst on January 25, 2009
  44. GRB 090118: no afterglow candidate
  45. GRB 090123: GROND detection
  46. 1E1547.0-5408: Swift detection of dust halo
  47. GRB 090123: Swift XRT refined analysis
  48. GRB 090123: Swift/UVOT Observations
  49. AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
  50. GRB 090123: Swift-BAT refined analysis
  51. GRB090123: Enhanced Swift-XRT position
  52. GRB 090123: Swift detection of a burst
  53. AXP 1E1547.0-5408: long bursts with INTEGRAL SPI-ACS
  54. GRB 090118: Swift XRT Observations - Confirmation of an Afterglow
  55. Swift-BAT trigger 340734 is not a GRB
  56. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  57. AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
  58. GRB 090117C: Suzaku WAM observation of the prompt emission
  59. AXP 1E1547.0-5408: Fermi GBM observations
  60. Trigger 340734: Swift detection of a possible short burst
  61. AXP 1E1547.0-5408 activity with SGR bursts
  62. GRB 090118: Subaru NIR Observation
  63. GRB 090118: KPNO 4m 2nd Epoch Observations
  64. GRB 090118 (BATSS): GRT Optical Observation
  65. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  66. GRB 090118: Swift-XRT observations
  67. GRB090118 Swift/UVOT upper limits
  68. GRB 090118: GROND Upper Limits
  69. GRB 090118: Possible burst detection from Swift-BAT slew data
  70. GRB 090117B : Fermi GBM detection
  71. GRB 090117: confirmation of the X-ray afterglow
  72. GRB 090117C - Fermi GRB Detection
  73. GRB 090117 - Fermi GBM Observations
  74. GRB 090117: GROND Upper Limits
  75. GRB090117 Swift/UVOT upper limits
  76. GRB090117: Swift-XRT detection of a possible candidate afterglow
  77. GRB 090117 - SuperAGILE Localization of a long GRB
  78. GRB090102: MAGIC telescope GeV observation
  79. GRB 090112B: Suzaku WAM observation of the prompt emission
  80. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  81. GRB 090113: Swift UVOT upper limits
  82. GRB 090113: GROND Upper Limits
  83. GRB 090113: Swift-XRT refined analysis
  84. GRB 090113: Observations from NOT
  85. GRB 090113: Enhanced Swift-XRT position
  86. GRB 090113: Swift-BAT refined analysis
  87. GRB 090113: ROTSE-III Optical Limits
  88. GRB090113: XRT position
  89. GRB 090112B: Fermi GBM Detection
  90. GRB 090113: Swift detection of a burst
  91. GRB 090112: Fermi GBM detection
  92. GRB 090109: Fermi GBM detection
  93. GRB 090108B: Fermi GBM detection
  94. GRB 090111, Swift-BAT refined analysis
  95. GRB 090111: Swift UVOT Upper Limits
  96. GRB 090108: Fermi GBM Detection
  97. GRB 090111: Swift-XRT refined analysis
  98. GRB 090111: Enhanced Swift-XRT position
  99. GRB 090111: Swift detection of a burst
  100. GRB 090107B: Suzaku WAM observation of the prompt emission

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