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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 111228A: GMG optical observation
  2. GRB 111228A: Swift-XRT refined Analysis
  3. GRB 111228A: NOT redshift
  4. GRB111228A: TNG spectroscopy analysis
  5. FERMI GRB111228.45: MASTER observations
  6. GRB 111228A: Gemini South Redshift
  7. GRB 111228A: PAIRITEL NIR Detection
  8. GRB 111228A: MMT Redshift
  9. GRB 111228A: TAROT La Silla observatory observations
  10. GRB 111228A: GROND observations
  11. GRB 111228A: MASTER OT observations
  12. GRB111228A: Errata of MITSuME Okayama about GRB name in GCNC 12743
  13. GRB 111228A: GRAS017 optical observations
  14. GRB 111228A: IAC80 BVI-band observations
  15. GRB 111228A: Swift/UVOT Detection
  16. GRB 111228A: Skynet/Dolomiti Optical Observations
  17. GRB 111228A: NOT optical observation
  18. GRB 111228A, Swift-BAT refined analysis
  19. GRB 111228A: optical observations
  20. GRB 111228A: Enhanced Swift-XRT position
  21. GRB 111228A: TAROT Calern observatory. OT decay stopped
  22. GRB 111228A, optical observations
  23. GRB 111228A: Fermi GBM observation
  24. GRB111228A: MITSuME Okayama Optical Observation
  25. GRB 111228A: TAROT Calern observatory. OT seems still bright
  26. GRB 111228A: Possible host galaxy in the SDSS arhive
  27. GRB 111225A, optical observations
  28. XMM-Newton observation of the short GRB 111020A
  29. GRB 111228A: Xinglong TNT confirms the optical afterglow
  30. GRB 111228A: Swift detection of a burst with an optical counterpart
  31. GRB 111205A: optical observations
  32. GRB 111225A: Swift/UVOT Observations
  33. GRB 111215A: Keck/LRIS Imaging
  34. GRB 111225A: Keck/LRIS Afterglow Photometry
  35. GRB 111222A : Suzaku WAM observation of the prompt emission
  36. GRB 111225A: PAIRITEL NIR Upper Limits
  37. GRB111225A: MITSuME Okayama optical upper limits
  38. GRB 111225A: GRT Optical Observation
  39. GRB 111225A: 1.23m CAHA optical observations
  40. GRB 111225A: Swift-XRT refined Analysis
  41. GRB 111225A, Swift-BAT refined analysis
  42. GRBv111225A: Xinglong TNT optical afterglow
  43. GRB 111225A: Enhanced Swift-XRT position
  44. GRB 111225A: Super-LOTIS early detection
  45. GRB 111225A: TAROT Calern observatory optical detection
  46. GRB 111225A: TAROT Calern observatory optical observations
  47. GRB 111225A: Swift detection of a burst with an optical counterpart
  48. GRB111222A: GMG optical observation
  49. GRB 111222A: Xinglong TNT observation
  50. GRB 111222A: Swift/UVOT Observations
  51. GRB 111222A: Swift-XRT observations
  52. Konus-Wind observation of GRB 111222A
  53. IPN Triangulation of GRB 111222A (short/hard/intense)
  54. GRB 111210A: optical upper limit of Mt. Terskol observatory
  55. Trigger 510075 is not a GRB
  56. GRB 111215A: EVLA observations
  57. GRB111215A: CARMA Detection
  58. XRT GRB Catalogue now live and online
  59. GRB 111103B: optical upper limit
  60. GRB 110820A: optical observations in Maidanak observatory
  61. GRB 111103A: optical upper limit of Mt. Terskol observatory
  62. GRB 111215B: Suzaku WAM observation of the prompt emission
  63. GRB 111211A: optical ovservations at Mt. Terskol observatory
  64. GRB111215A: optical upper limit
  65. GRB 111215B: Swift/UVOT Upper Limits
  66. Konus-Wind observation of GRB 111215B
  67. GRB 111215B: Swift-XRT observations
  68. GRB 111205A: Confirmation of X-ray Afterglow
  69. IPN Triangulation of GRB 111215B (long/intense)
  70. GRB111215A: Pre-Outburst Palomar 48 inch Imaging
  71. GRB 111215A: WHT, LT and NOT imaging
  72. GRB 111215A: TNG K-band observations
  73. GRB 111215A: MITSuME Okayama Optical upper limits
  74. GRB 111215A: Swift/UVOT Upper Limits
  75. GRB 111215A: Swift-XRT refined Analysis
  76. Possible detection of pre-trigger X-ray emission from GRB 111215A by MAXI/GSC
  77. GRB 111215A: Enhanced Swift-XRT position
  78. GRB 111215A: Swift-BAT refined analysis
  79. GRB 111215A: OSN I-band observations
  80. GRB 111215A: MASTER-Net optical prompt and follow up observations
  81. GRB 111215A, Optical Observations
  82. GRB 111215A: MITSuME Akeno Optical upper limits
  83. GRB 111209A: RAPTOR Limits Before and During the Gamma-ray Emitting Interval
  84. GRB 111215A: GMG optical upper limit
  85. GRB 111215A : Xinglong TNT upper limit
  86. GRB 111215A: Swift detection of a burst
  87. GRB 111201A, the review of the sky area in plate archive
  88. GRB 111212A: GROND observations
  89. GRB 111211A: Swift/UVOT Detection
  90. GRB 111211A: VLT/X-shooter redshift
  91. Konus-Wind observation of GRB 111211A
  92. GRB 111211A: NOT afterglow confirmation
  93. GRB 111212A: Swift-XRT refined Analysis
  94. GRB 111211A: Swift/XRT target of opportunity observation
  95. GRB 111212A: Swift/UVOT Upper Limits
  96. GRB 111212A: Swift-BAT refined analysis
  97. GRB 111212A: Enhanced Swift-XRT position
  98. GRB 111212A: Swift-XRT observations
  99. GRB 111211A: GROND afterglow candidate
  100. GRB 111212A: Swift detection of a burst

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