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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. GRB060204B: Swift/UVOT refined analysis
  2. GRB 060204C: optical observations
  3. Swift XRT Observation of GRB 060204C
  4. GRB 060204B: Swift-BAT refined analysis
  5. GRB 060204B: ART early limit
  6. GRB060204B: Swift XRT Team Refined Analysis
  7. GRB 060204C: OSN limits
  8. GRB 060204b: Keck/LRIS Afterglow Confirmation
  9. GRB 060204C: BOOTES-IR optical limits
  10. GRB 060204C: Liverpool Telescopes optical limit
  11. GRB 060204C: ROTSE-III Optical Limits
  12. GRB 060204C: Swift-BAT detection of a burst
  13. GRB 060124: Radio Observations
  14. GRB060204B: Faulkes OT candidate
  15. GRB 060204B: ART optical limit
  16. GRB 060204A: further INTEGRAL results
  17. GRB060204B, optical observation
  18. GRB060204B - SDSS pre-burst observations
  19. GRB 060203: Swift-BAT refined analysis
  20. GRB 060204B: Swift detection of a burst
  21. GRB 060204: a long GRB detected by INTEGRAL
  22. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  23. GRB 060203: RTT150 optical observations
  24. GRB060203: Swift XRT Team Refined Analysis
  25. GRB060203 - Swift UVOT observation
  26. Swift-BAT trigger is GRB 060203
  27. GRB 060203: IR Counterpart
  28. GRB060203: Observations with SARA
  29. GRB 060203: P60 Confirmation of Optical Afterglow
  30. Possible GRB 060203: candidate optical counterpart
  31. Swift BAT Trigger 180151: Swift XRT source detection
  32. Possible GRB 060203: optical observations at Asiago
  33. GRB 060202: PROMPT Observations
  34. Swift-BAT trigger 180151 is unknown origin at this time
  35. GRB 060202: GETS observation
  36. GRB 060202: Gemini-N J, H, K_s observations
  37. GRB 060202 : Kiso B and R band limit
  38. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  39. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  40. GRB 060202: Refined analysis of the Swift-BAT burst
  41. GRB060202, optical observation
  42. GRB 060202: Swift/UVOT upper limits
  43. GRB 060202: Swift XRT Team Refined Analysis
  44. GRB 060202 : Lulin R and I band limit
  45. GRB060202: Faulkes North observation
  46. GRB 060202: Swift detection of a burst
  47. GRB 060121: Gemini Late-time Observations
  48. Erratum: SDSS pre-burst observations of GRB fields
  49. GRB 060130: PROMPT Observations
  50. GRB060130: Further R-band imaging
  51. GRB 060130: Swift/XRT observation
  52. GRB 051211A: MDM Observations
  53. GRB 060123: Gemini spectroscopy of the putative host galaxy
  54. GRB 060123: VLA Radio Observations
  55. GRB060130: Optical imaging
  56. GRB060130: REM infrared observations
  57. GRB 060130, SMARTS optical observations
  58. GRB 060130: FRAM optical observations
  59. GRB 060130: further INTEGRAL IBIS results
  60. GRB 060130: a long GRB detected with INTEGRAL
  61. Possible GRB 051221B: MDM Correction
  62. GRB050121: optical observation
  63. GRB050121b: optical observation
  64. GRB 060121: Confirmation of NIR Afterglow
  65. GRB060124: optical observation
  66. GRB060124: optical observations
  67. GRB 060123: Swift refined analysis of an unusual GRB
  68. GRB060124, BVRcIc field calibration
  69. GRB060105: refined analysis of the Suzaku observation
  70. GRB060124 optical observations
  71. GRB 060121: Probable Detection of NIR Afterglow
  72. GRB060124: optical observation
  73. GRB 060116 HST observations
  74. GRB 060124: HETE detection and spectrum of the main peak
  75. Refined XRT Position for GRB 060123
  76. Konus-Wind observation of GRB 060124
  77. GRB060124: detailed XRT analysis
  78. GRB 060124 Optical Observations
  79. GRB 060124: ART optical limits during the burst
  80. GRB060123: Optical and IR Imaging
  81. GRB 060123: P200 Observations
  82. GRB 060124: Keck optical spectrum
  83. GRB 060124: Keck Absorption Redshift
  84. GRB 060124: MDM Optical Spectrum
  85. GRB 060124: XRT refined analysis
  86. GRB 060124: R band Observations
  87. GRB 060124 : Optical observation at Xinglong and Kiso
  88. GRB060124: optical observations at Asiago
  89. GRB 060124: Extremely long burst, Swift-BAT refined analysis
  90. GRB060123: SDSS pre-burst observations
  91. GRB 060123: Swift detection of a very long, faint burst
  92. GRB 060116: Further analysis of VLT photometry and optical spectroscopy
  93. GRB 060121: OHP optical limits
  94. GRB 060124: TAROT optical limits
  95. GRB 060124: Swift/UVOT Observation
  96. GRB 060124: Confirmation of the Afterglow
  97. GRB 060124: XRT position
  98. GRB 060124: Optical Afterglow Candidate from Tautenburg
  99. GRB060124, optical observation
  100. GRB 050124 : Kiso Optical limit

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