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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 110318B: Swift/UVOT Non-Detection of an Afterglow
  2. GRB 110318B: Swift detection of a burst
  3. GRB 110318A: Swift detection of a burst
  4. Fermi GBM trigger 321944155 (110316205) is not a GRB
  5. GRB 110315A: RTT150 optical observations
  6. GRB 110315A: Swift/UVOT Upper Limits
  7. GRB 110315A: Swift-XRT refined Analysis
  8. GRB 110315A: Swift-BAT refined analysis
  9. GRB 110315A: Enhanced Swift-XRT position
  10. GRB 110315A: MASTER early optical observations
  11. GRB 110315A: Swift detection of a burst
  12. GRB110312A: MITSuME Okayama Optical upper limits
  13. GRB 110312A: RTT150 optical observations
  14. GRB 110312A: Swift/UVOT Upper Limits
  15. GRB 110312A: Swift-XRT refined Analysis
  16. GRB 110312A: GROND Upper Limits
  17. GRB 110312A: Enhanced Swift-XRT position
  18. GRB 110312A: Swift-BAT refined analysis
  19. GRB 110312A: Swift detection of a burst
  20. GRB 110305A: REM detection of a possible NIR afterglow
  21. GRB110305A: MITSuME Ishigakijima Optical upper limits
  22. GRB 110305A: Swift/UVOT Upper Limits
  23. GRB 110305A: Swift-XRT refined Analysis
  24. GRB 110305A: Enhanced Swift-XRT position
  25. GRB 110305A: Swift-BAT refined analysis
  26. IBAS trigger n. 6138 is not a GRB
  27. GRB 110305A: GROND Detection of Optical Afterglow
  28. GRB 110305A: Swift detection of a burst
  29. GRB 110223A: optical upper limits
  30. GRB 110301A: Fermi GBM detection
  31. GRB101225A: early EVLA Observations of Christmas Burst
  32. Swift/UVOT observations of GRB110223A
  33. No IPN GRB detected in conjunction with candidate GRB 110215
  34. GRB GRB 110223A: MASTER VWF early optical observations
  35. IBAS distribution of coordinates for low significance INTEGRAL GRB triggers
  36. Swift/UVOT observations of GRB110223b
  37. GRB 110223A: Swift-BAT refined analysis
  38. GRB 110223A : early optical limit by "Pi of the Sky"
  39. GRB 110223A: Liverpool Telescope observations
  40. GRB 110223A: Swift-XRT refined Analysis
  41. GRB 110223B: Swift-XRT refined Analysis
  42. GRB 110223A: Enhanced Swift-XRT position
  43. GRB 110223B: Enhanced Swift-XRT position
  44. GRB 110223B: Swift-BAT refined analysis
  45. GRB 110223B: GROND Detection of Optical Afterglow Candidate
  46. GRB 110223A: Observations from BOOTES-2
  47. GRB 110223B: Swift detection of a burst
  48. GRB 110223A: Swift detection of a burst
  49. GRB 101225A, the review of the sky area in plate archives
  50. OT 110215: Further NIR observations from NOT of the GRB candidate
  51. GRB 110213B: Swift/UVOT observations
  52. GRB110213B: X-ray afterglow confirmation
  53. Fermi GBM detection of an SGR-like burst
  54. Swift XRT and UVOT Observations of OT 110215
  55. OT 110215: NIR observations from NOT of GRB candidate
  56. GRB 110213A: optical observations in CrAO
  57. GRB 110213B: GROND observations of the optical/NIR afterglow
  58. GRB 110213A: optical observations in Mondy
  59. Fermi GBM trigger 319534757 (110216319) is not a GRB
  60. GRB110205A: EVLA Observations
  61. OT 110215: possible GRB from 2MASS J00264184+8324093
  62. Swift/UVOT observations of GRB110210a.
  63. GRB 110210A: optical upper limit
  64. GRB 110213B: Gemini South Redshift
  65. GRB 110213B: Possible Host Galaxy in SDSS Stripe 82 Imaging
  66. GRB 110210A: ROVOR Upper Limit
  67. GRB 110213A: YNAO-GMG Observations
  68. GRB 110213B: P60 Optical Afterglow Candidate
  69. GRB 110213A: TNT optical observations
  70. GRB110213A: RAPTOR Early Optical Peak and Plateau Measurements
  71. GRB 110212A: Swift XRT and UVOT observations
  72. Swift GRB110213A: interesting behaviour
  73. GRB 110213A: Fermi GBM observation
  74. GRB 110205A: Konkoly optical observations
  75. GRB 110213B: Swift XRT observation
  76. GRB 110213A: MITSuME Akeno Optical Observation
  77. Konus-Wind observation of GRB 110213A
  78. Konus-Wind observation of GRB 110213B
  79. GRB 110213A: Swift-XRT refined Analysis
  80. GRB 110213B: MAXI/GSC refined analysis
  81. GRB110213A: MITSuME Okayama Optical Observation
  82. GRB 110213A: Swift/UVOT refined analysis
  83. GRB 110213A: THO optical observations
  84. GRB 110213B: MAXI/GSC detection of a probable GRB
  85. GRB 110213A: Lightbuckets Optical Observations
  86. GRB 110213A, Swift-BAT refined analysis
  87. GRB 110213A: optical observations
  88. GRB 110213A: Enhanced Swift-XRT position
  89. GRB110212A: MITSuME Okayama optical upper limits
  90. GRB 110213A: KAIT observations
  91. GRB 110213A: GRAS011 optical observations
  92. GRB 110213A: Bok Telescope Redshift
  93. GRB 110213A: ROTSE-III Detection of Optical Counterpart
  94. GRB 110213A: P60 Optical Afterglow Detection
  95. GRB 110213A: Swift detection of a burst with optical afterglow
  96. GRB 110212A: GRT Optical Observation
  97. GRB 110212A, Swift-BAT refined analysis
  98. GRB 110212A: SARA-N Optical Limits
  99. GRB110212A: BOOTES-2/TELMA optical limits
  100. GRB 110212A: ROTSE-III Optical Limits

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