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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. Swift BAT Trigger 180151: Swift XRT source detection
  2. Possible GRB 060203: optical observations at Asiago
  3. GRB 060202: PROMPT Observations
  4. Swift-BAT trigger 180151 is unknown origin at this time
  5. GRB 060202: GETS observation
  6. GRB 060202: Gemini-N J, H, K_s observations
  7. GRB 060202 : Kiso B and R band limit
  8. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  9. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  10. GRB 060202: Refined analysis of the Swift-BAT burst
  11. GRB060202, optical observation
  12. GRB 060202: Swift/UVOT upper limits
  13. GRB 060202: Swift XRT Team Refined Analysis
  14. GRB 060202 : Lulin R and I band limit
  15. GRB060202: Faulkes North observation
  16. GRB 060202: Swift detection of a burst
  17. GRB 060121: Gemini Late-time Observations
  18. Erratum: SDSS pre-burst observations of GRB fields
  19. GRB 060130: PROMPT Observations
  20. GRB060130: Further R-band imaging
  21. GRB 060130: Swift/XRT observation
  22. GRB 051211A: MDM Observations
  23. GRB 060123: Gemini spectroscopy of the putative host galaxy
  24. GRB 060123: VLA Radio Observations
  25. GRB060130: Optical imaging
  26. GRB060130: REM infrared observations
  27. GRB 060130, SMARTS optical observations
  28. GRB 060130: FRAM optical observations
  29. GRB 060130: further INTEGRAL IBIS results
  30. GRB 060130: a long GRB detected with INTEGRAL
  31. Possible GRB 051221B: MDM Correction
  32. GRB050121: optical observation
  33. GRB050121b: optical observation
  34. GRB 060121: Confirmation of NIR Afterglow
  35. GRB060124: optical observation
  36. GRB060124: optical observations
  37. GRB 060123: Swift refined analysis of an unusual GRB
  38. GRB060124, BVRcIc field calibration
  39. GRB060105: refined analysis of the Suzaku observation
  40. GRB060124 optical observations
  41. GRB 060121: Probable Detection of NIR Afterglow
  42. GRB060124: optical observation
  43. GRB 060116 HST observations
  44. GRB 060124: HETE detection and spectrum of the main peak
  45. Refined XRT Position for GRB 060123
  46. Konus-Wind observation of GRB 060124
  47. GRB060124: detailed XRT analysis
  48. GRB 060124 Optical Observations
  49. GRB 060124: ART optical limits during the burst
  50. GRB060123: Optical and IR Imaging
  51. GRB 060123: P200 Observations
  52. GRB 060124: Keck optical spectrum
  53. GRB 060124: Keck Absorption Redshift
  54. GRB 060124: MDM Optical Spectrum
  55. GRB 060124: XRT refined analysis
  56. GRB 060124: R band Observations
  57. GRB 060124 : Optical observation at Xinglong and Kiso
  58. GRB060124: optical observations at Asiago
  59. GRB 060124: Extremely long burst, Swift-BAT refined analysis
  60. GRB060123: SDSS pre-burst observations
  61. GRB 060123: Swift detection of a very long, faint burst
  62. GRB 060116: Further analysis of VLT photometry and optical spectroscopy
  63. GRB 060121: OHP optical limits
  64. GRB 060124: TAROT optical limits
  65. GRB 060124: Swift/UVOT Observation
  66. GRB 060124: Confirmation of the Afterglow
  67. GRB 060124: XRT position
  68. GRB 060124: Optical Afterglow Candidate from Tautenburg
  69. GRB060124, optical observation
  70. GRB 050124 : Kiso Optical limit
  71. GRB 060124: Optical Observations at Tautenburg
  72. GRB 060117: Suzaku WAM observation of the prompt emission
  73. GRB060124:MASTER optical observation
  74. GRB 060111B: Suzaku WAM observation of the prompt emission
  75. GRB 060124: Swift-BAT detection of a burst
  76. GRB 060116: Radio Detection
  77. GRB 060116: MARGE optical observations
  78. GRB 060121: Swift/UVOT upper limits
  79. GRB 060121: Liverpool Telescopes optical limits
  80. GRB 060121: Swift XRT refined analysis
  81. Konus-Wind observation of GRB 060121
  82. GRB 060121: I-band Limits
  83. GRB 060121: Confirmation of Afterglow
  84. GRB 060121: candidate optical counterpart
  85. GRB 060121: Swift XRT refined position
  86. GRB060121: SARA Observations
  87. GRB 060121: optical observations
  88. GRB 060121: Infrared Observations
  89. GRB 060121: optical observations
  90. GRB 060121: Optical imaging
  91. GRB060121 - SDSS pre-burst observations
  92. GRB 060121: A short-hard GRB in a cluster?
  93. GRB 060121 (=H4010): Results of preliminary spectral analysis
  94. GRB 060121: A bright short/hard GRB localized by HETE-2 SXC
  95. GRB 060121: A bright short/hard GRB localized by HETE-2 WXM
  96. HETE Alert 4006: MASTER promt optical limit
  97. GRB 060117: PROMPT Observations
  98. GRB060117 - ATCA 3/6cm radio limits - correction
  99. GRB060117 - ATCA 3/6cm radio limits
  100. GRB 060116: photometric redshift - the farthest GRB?

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