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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 060206: IR Detection of the Afterglow
  2. GRB 060206: Lick 3m Spectroscopy
  3. GRB 060204A: ROSAT Pointing
  4. GRB 060206: Super-LOTIS observations
  5. GRB060204A: Swift/UVOT observations
  6. GRB 060206: Swift-BAT refined analysis
  7. GRB 060206 : Lulin optical observations
  8. GRB060206: SDSS Pre-Burst Observations
  9. GRB060206: Swift XRT Refined Analysis
  10. GRB060206: Liverpool Telescope observation
  11. GRB 060206: Spectroscopic Redshift
  12. GRB060206: P60 Optical Observations
  13. GRB 060206: KAIT observations
  14. GRB060206: Swift XRT Position
  15. GRB060206: SARA Detection
  16. GRB 060206: RAPTOR observations of afterglow candidate variability.
  17. GRB 060206: High redshift burst
  18. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  19. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  20. GRB060206: Optical afterglow
  21. GRB060206: Swift-BAT detection of a burst
  22. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  23. GRB060203: WHT Z-band observations
  24. BAT GRB 060204C is probably not a GRB
  25. GRB060204C: optical observation
  26. GRB 060204B: BVRi-band detections of optical afterglow
  27. GRB 060204A: Swift XRT upper limit
  28. GRB 060204A: FRAM optical observations
  29. GRB060204B: Swift/UVOT refined analysis
  30. GRB 060204C: optical observations
  31. Swift XRT Observation of GRB 060204C
  32. GRB 060204B: Swift-BAT refined analysis
  33. GRB 060204B: ART early limit
  34. GRB060204B: Swift XRT Team Refined Analysis
  35. GRB 060204C: OSN limits
  36. GRB 060204b: Keck/LRIS Afterglow Confirmation
  37. GRB 060204C: BOOTES-IR optical limits
  38. GRB 060204C: Liverpool Telescopes optical limit
  39. GRB 060204C: ROTSE-III Optical Limits
  40. GRB 060204C: Swift-BAT detection of a burst
  41. GRB 060124: Radio Observations
  42. GRB060204B: Faulkes OT candidate
  43. GRB 060204B: ART optical limit
  44. GRB 060204A: further INTEGRAL results
  45. GRB060204B, optical observation
  46. GRB060204B - SDSS pre-burst observations
  47. GRB 060203: Swift-BAT refined analysis
  48. GRB 060204B: Swift detection of a burst
  49. GRB 060204: a long GRB detected by INTEGRAL
  50. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  51. GRB 060203: RTT150 optical observations
  52. GRB060203: Swift XRT Team Refined Analysis
  53. GRB060203 - Swift UVOT observation
  54. Swift-BAT trigger is GRB 060203
  55. GRB 060203: IR Counterpart
  56. GRB060203: Observations with SARA
  57. GRB 060203: P60 Confirmation of Optical Afterglow
  58. Possible GRB 060203: candidate optical counterpart
  59. Swift BAT Trigger 180151: Swift XRT source detection
  60. Possible GRB 060203: optical observations at Asiago
  61. GRB 060202: PROMPT Observations
  62. Swift-BAT trigger 180151 is unknown origin at this time
  63. GRB 060202: GETS observation
  64. GRB 060202: Gemini-N J, H, K_s observations
  65. GRB 060202 : Kiso B and R band limit
  66. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  67. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  68. GRB 060202: Refined analysis of the Swift-BAT burst
  69. GRB060202, optical observation
  70. GRB 060202: Swift/UVOT upper limits
  71. GRB 060202: Swift XRT Team Refined Analysis
  72. GRB 060202 : Lulin R and I band limit
  73. GRB060202: Faulkes North observation
  74. GRB 060202: Swift detection of a burst
  75. GRB 060121: Gemini Late-time Observations
  76. Erratum: SDSS pre-burst observations of GRB fields
  77. GRB 060130: PROMPT Observations
  78. GRB060130: Further R-band imaging
  79. GRB 060130: Swift/XRT observation
  80. GRB 051211A: MDM Observations
  81. GRB 060123: Gemini spectroscopy of the putative host galaxy
  82. GRB 060123: VLA Radio Observations
  83. GRB060130: Optical imaging
  84. GRB060130: REM infrared observations
  85. GRB 060130, SMARTS optical observations
  86. GRB 060130: FRAM optical observations
  87. GRB 060130: further INTEGRAL IBIS results
  88. GRB 060130: a long GRB detected with INTEGRAL
  89. Possible GRB 051221B: MDM Correction
  90. GRB050121: optical observation
  91. GRB050121b: optical observation
  92. GRB 060121: Confirmation of NIR Afterglow
  93. GRB060124: optical observation
  94. GRB060124: optical observations
  95. GRB 060123: Swift refined analysis of an unusual GRB
  96. GRB060124, BVRcIc field calibration
  97. GRB060105: refined analysis of the Suzaku observation
  98. GRB060124 optical observations
  99. GRB 060121: Probable Detection of NIR Afterglow
  100. GRB060124: optical observation

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