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

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Download all Circulars as a .tar.gz archive (updated once a day):
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