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

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