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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 060204C: XRT analysis of Swift J061223.0+701243.9
  2. GRB060203: WHT Z-band observations
  3. BAT GRB 060204C is probably not a GRB
  4. GRB060204C: optical observation
  5. GRB 060204B: BVRi-band detections of optical afterglow
  6. GRB 060204A: Swift XRT upper limit
  7. GRB 060204A: FRAM optical observations
  8. GRB060204B: Swift/UVOT refined analysis
  9. GRB 060204C: optical observations
  10. Swift XRT Observation of GRB 060204C
  11. GRB 060204B: Swift-BAT refined analysis
  12. GRB 060204B: ART early limit
  13. GRB060204B: Swift XRT Team Refined Analysis
  14. GRB 060204C: OSN limits
  15. GRB 060204b: Keck/LRIS Afterglow Confirmation
  16. GRB 060204C: BOOTES-IR optical limits
  17. GRB 060204C: Liverpool Telescopes optical limit
  18. GRB 060204C: ROTSE-III Optical Limits
  19. GRB 060204C: Swift-BAT detection of a burst
  20. GRB 060124: Radio Observations
  21. GRB060204B: Faulkes OT candidate
  22. GRB 060204B: ART optical limit
  23. GRB 060204A: further INTEGRAL results
  24. GRB060204B, optical observation
  25. GRB060204B - SDSS pre-burst observations
  26. GRB 060203: Swift-BAT refined analysis
  27. GRB 060204B: Swift detection of a burst
  28. GRB 060204: a long GRB detected by INTEGRAL
  29. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  30. GRB 060203: RTT150 optical observations
  31. GRB060203: Swift XRT Team Refined Analysis
  32. GRB060203 - Swift UVOT observation
  33. Swift-BAT trigger is GRB 060203
  34. GRB 060203: IR Counterpart
  35. GRB060203: Observations with SARA
  36. GRB 060203: P60 Confirmation of Optical Afterglow
  37. Possible GRB 060203: candidate optical counterpart
  38. Swift BAT Trigger 180151: Swift XRT source detection
  39. Possible GRB 060203: optical observations at Asiago
  40. GRB 060202: PROMPT Observations
  41. Swift-BAT trigger 180151 is unknown origin at this time
  42. GRB 060202: GETS observation
  43. GRB 060202: Gemini-N J, H, K_s observations
  44. GRB 060202 : Kiso B and R band limit
  45. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  46. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  47. GRB 060202: Refined analysis of the Swift-BAT burst
  48. GRB060202, optical observation
  49. GRB 060202: Swift/UVOT upper limits
  50. GRB 060202: Swift XRT Team Refined Analysis
  51. GRB 060202 : Lulin R and I band limit
  52. GRB060202: Faulkes North observation
  53. GRB 060202: Swift detection of a burst
  54. GRB 060121: Gemini Late-time Observations
  55. Erratum: SDSS pre-burst observations of GRB fields
  56. GRB 060130: PROMPT Observations
  57. GRB060130: Further R-band imaging
  58. GRB 060130: Swift/XRT observation
  59. GRB 051211A: MDM Observations
  60. GRB 060123: Gemini spectroscopy of the putative host galaxy
  61. GRB 060123: VLA Radio Observations
  62. GRB060130: Optical imaging
  63. GRB060130: REM infrared observations
  64. GRB 060130, SMARTS optical observations
  65. GRB 060130: FRAM optical observations
  66. GRB 060130: further INTEGRAL IBIS results
  67. GRB 060130: a long GRB detected with INTEGRAL
  68. Possible GRB 051221B: MDM Correction
  69. GRB050121: optical observation
  70. GRB050121b: optical observation
  71. GRB 060121: Confirmation of NIR Afterglow
  72. GRB060124: optical observation
  73. GRB060124: optical observations
  74. GRB 060123: Swift refined analysis of an unusual GRB
  75. GRB060124, BVRcIc field calibration
  76. GRB060105: refined analysis of the Suzaku observation
  77. GRB060124 optical observations
  78. GRB 060121: Probable Detection of NIR Afterglow
  79. GRB060124: optical observation
  80. GRB 060116 HST observations
  81. GRB 060124: HETE detection and spectrum of the main peak
  82. Refined XRT Position for GRB 060123
  83. Konus-Wind observation of GRB 060124
  84. GRB060124: detailed XRT analysis
  85. GRB 060124 Optical Observations
  86. GRB 060124: ART optical limits during the burst
  87. GRB060123: Optical and IR Imaging
  88. GRB 060123: P200 Observations
  89. GRB 060124: Keck optical spectrum
  90. GRB 060124: Keck Absorption Redshift
  91. GRB 060124: MDM Optical Spectrum
  92. GRB 060124: XRT refined analysis
  93. GRB 060124: R band Observations
  94. GRB 060124 : Optical observation at Xinglong and Kiso
  95. GRB060124: optical observations at Asiago
  96. GRB 060124: Extremely long burst, Swift-BAT refined analysis
  97. GRB060123: SDSS pre-burst observations
  98. GRB 060123: Swift detection of a very long, faint burst
  99. GRB 060116: Further analysis of VLT photometry and optical spectroscopy
  100. GRB 060121: OHP optical limits

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