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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 Upper Limits
  2. GRB 110319B: GROND upper limits
  3. GRB 110319B: Swift-XRT afterglow candidate.
  4. GRB 110319B found in ground analysis of Swift-BAT data
  5. GRB 110319A: Swift/UVOT Detection
  6. GRB 110319A: Swift-BAT refined analysis
  7. GRB 110319A: Swift-XRT refined Analysis
  8. GRB 110318B: GROND upper limits
  9. GRB 110319A: Enhanced Swift-XRT position
  10. GRB 110319A: Swift detection of a burst
  11. GRB 110318B: Swift-XRT refined Analysis
  12. GRB 110318A: Fermi GBM detection
  13. GRB 110318B: Swift-BAT refined analysis
  14. GRB 110318B: Enhanced Swift-XRT position
  15. GRB 110318A: Swift-BAT refined analysis
  16. GRB 110318B: Swift/UVOT Non-Detection of an Afterglow
  17. GRB 110318B: Swift detection of a burst
  18. GRB 110318A: Swift detection of a burst
  19. Fermi GBM trigger 321944155 (110316205) is not a GRB
  20. GRB 110315A: RTT150 optical observations
  21. GRB 110315A: Swift/UVOT Upper Limits
  22. GRB 110315A: Swift-XRT refined Analysis
  23. GRB 110315A: Swift-BAT refined analysis
  24. GRB 110315A: Enhanced Swift-XRT position
  25. GRB 110315A: MASTER early optical observations
  26. GRB 110315A: Swift detection of a burst
  27. GRB110312A: MITSuME Okayama Optical upper limits
  28. GRB 110312A: RTT150 optical observations
  29. GRB 110312A: Swift/UVOT Upper Limits
  30. GRB 110312A: Swift-XRT refined Analysis
  31. GRB 110312A: GROND Upper Limits
  32. GRB 110312A: Enhanced Swift-XRT position
  33. GRB 110312A: Swift-BAT refined analysis
  34. GRB 110312A: Swift detection of a burst
  35. GRB 110305A: REM detection of a possible NIR afterglow
  36. GRB110305A: MITSuME Ishigakijima Optical upper limits
  37. GRB 110305A: Swift/UVOT Upper Limits
  38. GRB 110305A: Swift-XRT refined Analysis
  39. GRB 110305A: Enhanced Swift-XRT position
  40. GRB 110305A: Swift-BAT refined analysis
  41. IBAS trigger n. 6138 is not a GRB
  42. GRB 110305A: GROND Detection of Optical Afterglow
  43. GRB 110305A: Swift detection of a burst
  44. GRB 110223A: optical upper limits
  45. GRB 110301A: Fermi GBM detection
  46. GRB101225A: early EVLA Observations of Christmas Burst
  47. Swift/UVOT observations of GRB110223A
  48. No IPN GRB detected in conjunction with candidate GRB 110215
  49. GRB GRB 110223A: MASTER VWF early optical observations
  50. IBAS distribution of coordinates for low significance INTEGRAL GRB triggers
  51. Swift/UVOT observations of GRB110223b
  52. GRB 110223A: Swift-BAT refined analysis
  53. GRB 110223A : early optical limit by "Pi of the Sky"
  54. GRB 110223A: Liverpool Telescope observations
  55. GRB 110223A: Swift-XRT refined Analysis
  56. GRB 110223B: Swift-XRT refined Analysis
  57. GRB 110223A: Enhanced Swift-XRT position
  58. GRB 110223B: Enhanced Swift-XRT position
  59. GRB 110223B: Swift-BAT refined analysis
  60. GRB 110223B: GROND Detection of Optical Afterglow Candidate
  61. GRB 110223A: Observations from BOOTES-2
  62. GRB 110223B: Swift detection of a burst
  63. GRB 110223A: Swift detection of a burst
  64. GRB 101225A, the review of the sky area in plate archives
  65. OT 110215: Further NIR observations from NOT of the GRB candidate
  66. GRB 110213B: Swift/UVOT observations
  67. GRB110213B: X-ray afterglow confirmation
  68. Fermi GBM detection of an SGR-like burst
  69. Swift XRT and UVOT Observations of OT 110215
  70. OT 110215: NIR observations from NOT of GRB candidate
  71. GRB 110213A: optical observations in CrAO
  72. GRB 110213B: GROND observations of the optical/NIR afterglow
  73. GRB 110213A: optical observations in Mondy
  74. Fermi GBM trigger 319534757 (110216319) is not a GRB
  75. GRB110205A: EVLA Observations
  76. OT 110215: possible GRB from 2MASS J00264184+8324093
  77. Swift/UVOT observations of GRB110210a.
  78. GRB 110210A: optical upper limit
  79. GRB 110213B: Gemini South Redshift
  80. GRB 110213B: Possible Host Galaxy in SDSS Stripe 82 Imaging
  81. GRB 110210A: ROVOR Upper Limit
  82. GRB 110213A: YNAO-GMG Observations
  83. GRB 110213B: P60 Optical Afterglow Candidate
  84. GRB 110213A: TNT optical observations
  85. GRB110213A: RAPTOR Early Optical Peak and Plateau Measurements
  86. GRB 110212A: Swift XRT and UVOT observations
  87. Swift GRB110213A: interesting behaviour
  88. GRB 110213A: Fermi GBM observation
  89. GRB 110205A: Konkoly optical observations
  90. GRB 110213B: Swift XRT observation
  91. GRB 110213A: MITSuME Akeno Optical Observation
  92. Konus-Wind observation of GRB 110213A
  93. Konus-Wind observation of GRB 110213B
  94. GRB 110213A: Swift-XRT refined Analysis
  95. GRB 110213B: MAXI/GSC refined analysis
  96. GRB110213A: MITSuME Okayama Optical Observation
  97. GRB 110213A: Swift/UVOT refined analysis
  98. GRB 110213A: THO optical observations
  99. GRB 110213B: MAXI/GSC detection of a probable GRB
  100. GRB 110213A: Lightbuckets Optical Observations

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