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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. GRB060206: Liverpool Telescope observation
  2. GRB 060206: Spectroscopic Redshift
  3. GRB060206: P60 Optical Observations
  4. GRB 060206: KAIT observations
  5. GRB060206: Swift XRT Position
  6. GRB060206: SARA Detection
  7. GRB 060206: RAPTOR observations of afterglow candidate variability.
  8. GRB 060206: High redshift burst
  9. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  10. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  11. GRB060206: Optical afterglow
  12. GRB060206: Swift-BAT detection of a burst
  13. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  14. GRB060203: WHT Z-band observations
  15. BAT GRB 060204C is probably not a GRB
  16. GRB060204C: optical observation
  17. GRB 060204B: BVRi-band detections of optical afterglow
  18. GRB 060204A: Swift XRT upper limit
  19. GRB 060204A: FRAM optical observations
  20. GRB060204B: Swift/UVOT refined analysis
  21. GRB 060204C: optical observations
  22. Swift XRT Observation of GRB 060204C
  23. GRB 060204B: Swift-BAT refined analysis
  24. GRB 060204B: ART early limit
  25. GRB060204B: Swift XRT Team Refined Analysis
  26. GRB 060204C: OSN limits
  27. GRB 060204b: Keck/LRIS Afterglow Confirmation
  28. GRB 060204C: BOOTES-IR optical limits
  29. GRB 060204C: Liverpool Telescopes optical limit
  30. GRB 060204C: ROTSE-III Optical Limits
  31. GRB 060204C: Swift-BAT detection of a burst
  32. GRB 060124: Radio Observations
  33. GRB060204B: Faulkes OT candidate
  34. GRB 060204B: ART optical limit
  35. GRB 060204A: further INTEGRAL results
  36. GRB060204B, optical observation
  37. GRB060204B - SDSS pre-burst observations
  38. GRB 060203: Swift-BAT refined analysis
  39. GRB 060204B: Swift detection of a burst
  40. GRB 060204: a long GRB detected by INTEGRAL
  41. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  42. GRB 060203: RTT150 optical observations
  43. GRB060203: Swift XRT Team Refined Analysis
  44. GRB060203 - Swift UVOT observation
  45. Swift-BAT trigger is GRB 060203
  46. GRB 060203: IR Counterpart
  47. GRB060203: Observations with SARA
  48. GRB 060203: P60 Confirmation of Optical Afterglow
  49. Possible GRB 060203: candidate optical counterpart
  50. Swift BAT Trigger 180151: Swift XRT source detection
  51. Possible GRB 060203: optical observations at Asiago
  52. GRB 060202: PROMPT Observations
  53. Swift-BAT trigger 180151 is unknown origin at this time
  54. GRB 060202: GETS observation
  55. GRB 060202: Gemini-N J, H, K_s observations
  56. GRB 060202 : Kiso B and R band limit
  57. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  58. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  59. GRB 060202: Refined analysis of the Swift-BAT burst
  60. GRB060202, optical observation
  61. GRB 060202: Swift/UVOT upper limits
  62. GRB 060202: Swift XRT Team Refined Analysis
  63. GRB 060202 : Lulin R and I band limit
  64. GRB060202: Faulkes North observation
  65. GRB 060202: Swift detection of a burst
  66. GRB 060121: Gemini Late-time Observations
  67. Erratum: SDSS pre-burst observations of GRB fields
  68. GRB 060130: PROMPT Observations
  69. GRB060130: Further R-band imaging
  70. GRB 060130: Swift/XRT observation
  71. GRB 051211A: MDM Observations
  72. GRB 060123: Gemini spectroscopy of the putative host galaxy
  73. GRB 060123: VLA Radio Observations
  74. GRB060130: Optical imaging
  75. GRB060130: REM infrared observations
  76. GRB 060130, SMARTS optical observations
  77. GRB 060130: FRAM optical observations
  78. GRB 060130: further INTEGRAL IBIS results
  79. GRB 060130: a long GRB detected with INTEGRAL
  80. Possible GRB 051221B: MDM Correction
  81. GRB050121: optical observation
  82. GRB050121b: optical observation
  83. GRB 060121: Confirmation of NIR Afterglow
  84. GRB060124: optical observation
  85. GRB060124: optical observations
  86. GRB 060123: Swift refined analysis of an unusual GRB
  87. GRB060124, BVRcIc field calibration
  88. GRB060105: refined analysis of the Suzaku observation
  89. GRB060124 optical observations
  90. GRB 060121: Probable Detection of NIR Afterglow
  91. GRB060124: optical observation
  92. GRB 060116 HST observations
  93. GRB 060124: HETE detection and spectrum of the main peak
  94. Refined XRT Position for GRB 060123
  95. Konus-Wind observation of GRB 060124
  96. GRB060124: detailed XRT analysis
  97. GRB 060124 Optical Observations
  98. GRB 060124: ART optical limits during the burst
  99. GRB060123: Optical and IR Imaging
  100. GRB 060123: P200 Observations

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