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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 060203: RTT150 optical observations
  2. GRB060203: Swift XRT Team Refined Analysis
  3. GRB060203 - Swift UVOT observation
  4. Swift-BAT trigger is GRB 060203
  5. GRB 060203: IR Counterpart
  6. GRB060203: Observations with SARA
  7. GRB 060203: P60 Confirmation of Optical Afterglow
  8. Possible GRB 060203: candidate optical counterpart
  9. Swift BAT Trigger 180151: Swift XRT source detection
  10. Possible GRB 060203: optical observations at Asiago
  11. GRB 060202: PROMPT Observations
  12. Swift-BAT trigger 180151 is unknown origin at this time
  13. GRB 060202: GETS observation
  14. GRB 060202: Gemini-N J, H, K_s observations
  15. GRB 060202 : Kiso B and R band limit
  16. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  17. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  18. GRB 060202: Refined analysis of the Swift-BAT burst
  19. GRB060202, optical observation
  20. GRB 060202: Swift/UVOT upper limits
  21. GRB 060202: Swift XRT Team Refined Analysis
  22. GRB 060202 : Lulin R and I band limit
  23. GRB060202: Faulkes North observation
  24. GRB 060202: Swift detection of a burst
  25. GRB 060121: Gemini Late-time Observations
  26. Erratum: SDSS pre-burst observations of GRB fields
  27. GRB 060130: PROMPT Observations
  28. GRB060130: Further R-band imaging
  29. GRB 060130: Swift/XRT observation
  30. GRB 051211A: MDM Observations
  31. GRB 060123: Gemini spectroscopy of the putative host galaxy
  32. GRB 060123: VLA Radio Observations
  33. GRB060130: Optical imaging
  34. GRB060130: REM infrared observations
  35. GRB 060130, SMARTS optical observations
  36. GRB 060130: FRAM optical observations
  37. GRB 060130: further INTEGRAL IBIS results
  38. GRB 060130: a long GRB detected with INTEGRAL
  39. Possible GRB 051221B: MDM Correction
  40. GRB050121: optical observation
  41. GRB050121b: optical observation
  42. GRB 060121: Confirmation of NIR Afterglow
  43. GRB060124: optical observation
  44. GRB060124: optical observations
  45. GRB 060123: Swift refined analysis of an unusual GRB
  46. GRB060124, BVRcIc field calibration
  47. GRB060105: refined analysis of the Suzaku observation
  48. GRB060124 optical observations
  49. GRB 060121: Probable Detection of NIR Afterglow
  50. GRB060124: optical observation
  51. GRB 060116 HST observations
  52. GRB 060124: HETE detection and spectrum of the main peak
  53. Refined XRT Position for GRB 060123
  54. Konus-Wind observation of GRB 060124
  55. GRB060124: detailed XRT analysis
  56. GRB 060124 Optical Observations
  57. GRB 060124: ART optical limits during the burst
  58. GRB060123: Optical and IR Imaging
  59. GRB 060123: P200 Observations
  60. GRB 060124: Keck optical spectrum
  61. GRB 060124: Keck Absorption Redshift
  62. GRB 060124: MDM Optical Spectrum
  63. GRB 060124: XRT refined analysis
  64. GRB 060124: R band Observations
  65. GRB 060124 : Optical observation at Xinglong and Kiso
  66. GRB060124: optical observations at Asiago
  67. GRB 060124: Extremely long burst, Swift-BAT refined analysis
  68. GRB060123: SDSS pre-burst observations
  69. GRB 060123: Swift detection of a very long, faint burst
  70. GRB 060116: Further analysis of VLT photometry and optical spectroscopy
  71. GRB 060121: OHP optical limits
  72. GRB 060124: TAROT optical limits
  73. GRB 060124: Swift/UVOT Observation
  74. GRB 060124: Confirmation of the Afterglow
  75. GRB 060124: XRT position
  76. GRB 060124: Optical Afterglow Candidate from Tautenburg
  77. GRB060124, optical observation
  78. GRB 050124 : Kiso Optical limit
  79. GRB 060124: Optical Observations at Tautenburg
  80. GRB 060117: Suzaku WAM observation of the prompt emission
  81. GRB060124:MASTER optical observation
  82. GRB 060111B: Suzaku WAM observation of the prompt emission
  83. GRB 060124: Swift-BAT detection of a burst
  84. GRB 060116: Radio Detection
  85. GRB 060116: MARGE optical observations
  86. GRB 060121: Swift/UVOT upper limits
  87. GRB 060121: Liverpool Telescopes optical limits
  88. GRB 060121: Swift XRT refined analysis
  89. Konus-Wind observation of GRB 060121
  90. GRB 060121: I-band Limits
  91. GRB 060121: Confirmation of Afterglow
  92. GRB 060121: candidate optical counterpart
  93. GRB 060121: Swift XRT refined position
  94. GRB060121: SARA Observations
  95. GRB 060121: optical observations
  96. GRB 060121: Infrared Observations
  97. GRB 060121: optical observations
  98. GRB 060121: Optical imaging
  99. GRB060121 - SDSS pre-burst observations
  100. GRB 060121: A short-hard GRB in a cluster?

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