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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 060202: Swift/UVOT upper limits
  2. GRB 060202: Swift XRT Team Refined Analysis
  3. GRB 060202 : Lulin R and I band limit
  4. GRB060202: Faulkes North observation
  5. GRB 060202: Swift detection of a burst
  6. GRB 060121: Gemini Late-time Observations
  7. Erratum: SDSS pre-burst observations of GRB fields
  8. GRB 060130: PROMPT Observations
  9. GRB060130: Further R-band imaging
  10. GRB 060130: Swift/XRT observation
  11. GRB 051211A: MDM Observations
  12. GRB 060123: Gemini spectroscopy of the putative host galaxy
  13. GRB 060123: VLA Radio Observations
  14. GRB060130: Optical imaging
  15. GRB060130: REM infrared observations
  16. GRB 060130, SMARTS optical observations
  17. GRB 060130: FRAM optical observations
  18. GRB 060130: further INTEGRAL IBIS results
  19. GRB 060130: a long GRB detected with INTEGRAL
  20. Possible GRB 051221B: MDM Correction
  21. GRB050121: optical observation
  22. GRB050121b: optical observation
  23. GRB 060121: Confirmation of NIR Afterglow
  24. GRB060124: optical observation
  25. GRB060124: optical observations
  26. GRB 060123: Swift refined analysis of an unusual GRB
  27. GRB060124, BVRcIc field calibration
  28. GRB060105: refined analysis of the Suzaku observation
  29. GRB060124 optical observations
  30. GRB 060121: Probable Detection of NIR Afterglow
  31. GRB060124: optical observation
  32. GRB 060116 HST observations
  33. GRB 060124: HETE detection and spectrum of the main peak
  34. Refined XRT Position for GRB 060123
  35. Konus-Wind observation of GRB 060124
  36. GRB060124: detailed XRT analysis
  37. GRB 060124 Optical Observations
  38. GRB 060124: ART optical limits during the burst
  39. GRB060123: Optical and IR Imaging
  40. GRB 060123: P200 Observations
  41. GRB 060124: Keck optical spectrum
  42. GRB 060124: Keck Absorption Redshift
  43. GRB 060124: MDM Optical Spectrum
  44. GRB 060124: XRT refined analysis
  45. GRB 060124: R band Observations
  46. GRB 060124 : Optical observation at Xinglong and Kiso
  47. GRB060124: optical observations at Asiago
  48. GRB 060124: Extremely long burst, Swift-BAT refined analysis
  49. GRB060123: SDSS pre-burst observations
  50. GRB 060123: Swift detection of a very long, faint burst
  51. GRB 060116: Further analysis of VLT photometry and optical spectroscopy
  52. GRB 060121: OHP optical limits
  53. GRB 060124: TAROT optical limits
  54. GRB 060124: Swift/UVOT Observation
  55. GRB 060124: Confirmation of the Afterglow
  56. GRB 060124: XRT position
  57. GRB 060124: Optical Afterglow Candidate from Tautenburg
  58. GRB060124, optical observation
  59. GRB 050124 : Kiso Optical limit
  60. GRB 060124: Optical Observations at Tautenburg
  61. GRB 060117: Suzaku WAM observation of the prompt emission
  62. GRB060124:MASTER optical observation
  63. GRB 060111B: Suzaku WAM observation of the prompt emission
  64. GRB 060124: Swift-BAT detection of a burst
  65. GRB 060116: Radio Detection
  66. GRB 060116: MARGE optical observations
  67. GRB 060121: Swift/UVOT upper limits
  68. GRB 060121: Liverpool Telescopes optical limits
  69. GRB 060121: Swift XRT refined analysis
  70. Konus-Wind observation of GRB 060121
  71. GRB 060121: I-band Limits
  72. GRB 060121: Confirmation of Afterglow
  73. GRB 060121: candidate optical counterpart
  74. GRB 060121: Swift XRT refined position
  75. GRB060121: SARA Observations
  76. GRB 060121: optical observations
  77. GRB 060121: Infrared Observations
  78. GRB 060121: optical observations
  79. GRB 060121: Optical imaging
  80. GRB060121 - SDSS pre-burst observations
  81. GRB 060121: A short-hard GRB in a cluster?
  82. GRB 060121 (=H4010): Results of preliminary spectral analysis
  83. GRB 060121: A bright short/hard GRB localized by HETE-2 SXC
  84. GRB 060121: A bright short/hard GRB localized by HETE-2 WXM
  85. HETE Alert 4006: MASTER promt optical limit
  86. GRB 060117: PROMPT Observations
  87. GRB060117 - ATCA 3/6cm radio limits - correction
  88. GRB060117 - ATCA 3/6cm radio limits
  89. GRB 060116: photometric redshift - the farthest GRB?
  90. GRB 060117: pseudo-z from spectral parameters of the prompt emission
  91. Correction to GCN 4542 on GRB 060117
  92. Konus-Wind observation of GRB 060117
  93. GRB 060116: possible I-J dropout
  94. GRB 060116: UKIRT IR Observations
  95. GRB060108: photometric redshift determination
  96. GRB 060117: Refined analysis of the Swift-BAT burst
  97. GRB 060116: PROMPT Observations
  98. GRB 060117: FRAM refined analysis
  99. GRB 060117: FRAM optical afterglow candidate
  100. GRB 060117: nearby galaxy

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