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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 120229A: Magellan observations and limit on an optical afterglow
  2. GRB 120320A: Swift/UVOT Upper Limits
  3. GRB 120320A: MITSuME Okayama Optical upper limits
  4. GRB 120320A , optical observations
  5. GRB 120320A: BOOTES-4 optical upper limit
  6. GRB 120320A: Swift-XRT refined Analysis
  7. GRB 120320A, Swift-BAT refined analysis
  8. GRB 120320A: Gemini-N and UKIRT observations
  9. Fermi GBM trigger 120319.237 is not a GRB
  10. GRB 120320A: Enhanced Swift-XRT position
  11. Konus-Wind observation of GRB 120316A
  12. IPN Triangulation of GRB 120316A
  13. GRB 120320A: MASTER optical observations
  14. GRB 120320A: Swift detection of a burst
  15. GBM trigger 353549464 (GRB 120316A?) : High-energy photon emission in Fermi/LAT data
  16. GRB 111228A: possible detection of the SN with the TNG
  17. Trigger 517876 is a Swift detection of GX 5-1
  18. GRB 120302A: Swift XRT refined analysis
  19. GRB 120312A, the review of the sky area in plate archives
  20. GRB 120312A: CrAO optical upper limit
  21. GRB 120312A: Gemini and UKIRT imaging
  22. GRB 120311A, the review of the sky area in plate archives
  23. Fermi GBM triggers 120309.265 and 120309.402 are not GRBs
  24. Fermi GBM triggers 120305.186, 120305.802 and 120306.823 are not GRBs
  25. GRB 120311A: Optical follow-up
  26. GRB 120311B: Optical follow-up
  27. GRB 120311A: C88 optical limits
  28. GRB 120312A: Swift/UVOT Upper Limits
  29. GRB 120312A: MASTER-NET optical observations
  30. GRB 120312A: WHT candidate afterglow
  31. GRB 120312A: NOT observations
  32. GRB 120312A: Swift-XRT refined Analysis
  33. GRB 120312A: Swift-BAT refined analysis
  34. GRB 120311A: VLT/X-shooter observations
  35. GRB 120311B: C88 optical limits
  36. GRB 120312A: Swift detection of a burst
  37. GROND observations of GRB 120311A
  38. GRB 120311B: Swift/UVOT Upper Limits
  39. GRB 120311B: MITSuME Okayama Optical upper limits
  40. GRB 120311B: Faulkes Telescope North observations
  41. GRB 120311B: Swift-XRT refined Analysis
  42. GRB 120311A: Swift-XRT refined Analysis
  43. GRB 120311B: Enhanced Swift-XRT position
  44. GRB 120311B: Swift-BAT refined analysis
  45. GRB 120311B: Swift-XRT observations
  46. GRB 120311A, Swift-BAT refined analysis
  47. GRB 120311B: Swift detection of a burst
  48. GRB 120311A: Swift/UVOT Upper Limits
  49. GRB 120311A: CAHA 1.23m I-band early observations
  50. GRB 120311A: Enhanced Swift-XRT position
  51. GRB 120311A: Swift-XRT observations
  52. GRB 120311A: Liverpool Telescope optical candidate
  53. GRB 120311A: Swift detection of a burst
  54. GRB 120308A : LOAO optical observation
  55. GRB 120308A: RTT150 optical observations
  56. GRB 120302A: RTT150 optical observations
  57. GRB 120308A: 1.23m CAHA I-band observations
  58. GRB 120308A: Further PAIRITEL NIR Observations
  59. GRB120308A: MITSuME Ishigakijima Optical Upper Limits
  60. GRB 120308A: Swift/UVOT Detection
  61. GRB 120308A: Swift-XRT refined Analysis
  62. GRB 120308A: Enhanced Swift-XRT position
  63. GRB 120308A: Swift-BAT refined analysis
  64. GRB 120308A: IAC80 I-band observations
  65. GRB 120308A: PAIRITEL NIR observations
  66. GRB 120308A: confirmation of the optical afterglow
  67. GRB 120308A: Liverpool Telescope optical afterglow candidate
  68. GRB 120308A: Swift detection of a burst
  69. GRB 120305A: D50 optical limits
  70. GRB 120305A: Swift spectral lag analysis
  71. GRB 120302A, the review of the sky area in plate archives
  72. GRB 120302A: Fermi GBM Observation
  73. GRB 120302A: Swift-BAT refined position and a possible XRT and UVOT counterpart
  74. GRB 120305A: Swift/UVOT Upper Limits
  75. GRB 120305A: EVLA deep limit on a radio counterpart
  76. GRB 120305A: Swift-XRT refined Analysis
  77. GRB 120305A: Enhanced Swift-XRT position
  78. GRB 120305A: Swift-BAT refined analysis
  79. GRB 120305A - Liverpool Telescope Observations
  80. GRB 120305A: MASTER-NET early optical observations
  81. GRB 120305A: Swift detection of a short burst
  82. GRB 120302A: GROND detection of an afterglow candidate
  83. GRB 120302A, Swift-BAT refined analysis
  84. GRB 111222A: Swift observation on 2012 February 06/07
  85. GRB 120302A found in ground analysis of BAT data
  86. GRB 120229A: Spectral lag analysis
  87. GRB 120229A, Swift-BAT refined analysis
  88. GRB 120229A: Swift detection of a short burst
  89. Konus-Wind observation of GRB 120226A
  90. GRB 120226A: Fermi-GBM and Fermi-LAT detections; LAT position retraction
  91. GRB 120226A: Fermi-LAT data analysis
  92. IPN Triangulation of GRB 120226A
  93. GRB 120227A: RAPTOR Limit During the Gamma-Ray Emitting Interval
  94. GRB 120224A: VLT/X-shooter observations
  95. GRB 120224A: optical observation in Mondy observatory
  96. GRB 120226A: Fermi-LAT detection of a burst
  97. GRB 120224A: GROND detection of the afterglow candidate
  98. GRB 120219A, the review of the sky area in plate archives
  99. GRB 120224A: Swift-XRT refined Analysis
  100. Swift Trigger 516027 is CC Eri

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