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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 111020A: Swift-BAT refined analysis
  2. GRB 111020A: Enhanced Swift-XRT position
  3. GRB 111020A: BOOTES-3 Optical Upper Limit.
  4. GRB 111020A: Planned XMM-Newton observation
  5. GRB 111020A: Swift detection of a short burst
  6. GRB 111018A: Swift/UVOT Upper Limits
  7. GRB 110918A: Optical light curve for days 1.4 to 16.3
  8. GRB 111018A: Swift-BAT refined analysis
  9. Konus-Wind observation of GRB 111016B
  10. GRB 111018A: Swift-XRT refined Analysis
  11. GRB 111018A: GROND Upper Limits
  12. GRB 111018A: Enhanced Swift-XRT position
  13. IPN Triangulation of GRB 111016B (long duration, intense)
  14. GRB111016A : WIYN 3.5m NIR observations
  15. GRB 111018A: Swift detection of a burst
  16. GRB 111017A: Fermi GBM Detection
  17. GRB111016A: D50 optical limit
  18. GRB 111016A: Gemini Detection of the NIR Counterpart
  19. GRB 111016A: Swift/UVOT Detection of a Source
  20. GRB 111016A: Swift-BAT refined analysis
  21. GRB 111016A: P60 Afterglow Candidate
  22. GRB 111016A: MITSuME Akeno Optical upper limits
  23. GRB 111016A: Swift-XRT refined Analysis
  24. GRB 111016A: Enhanced Swift-XRT position
  25. GRB 111016A: Swift-XRT observations
  26. GRB 111016A: Swift detection of a burst
  27. GRB 110921A: optical observations
  28. GRB 111008A : miniTAO/ANIR NIR observations
  29. EVLA 22 GHz Detection of GRB 111008A
  30. GRB 111005A: ATCA 18 GHz decay
  31. GRB 111008A: Swift/UVOT Upper Limits
  32. Konus-Wind observation of GRB 111008A
  33. GRB 111008A: IAC80 I-band observations
  34. GRB 111008A: VLT/X-shooter spectroscopy
  35. GRB 111008A: Swift-XRT refined Analysis
  36. GRB 111008A: Gemini spectroscopic redshift
  37. GRB 111008A, GROND observations
  38. GRB 111008A: NOT optical observation
  39. GRB 111008A: Gemini optical counterpart
  40. GRB 111008A: Enhanced Swift-XRT position
  41. GRB 111008A, Swift-BAT refined analysis,
  42. GRB 111008A: Swift detection of a burst
  43. GRB 111005A: ATCA 18 GHz detection
  44. GRB 111005A: ATCA radio upper limit
  45. GRB 111005A : miniTAO/ANIR NIR observations
  46. GRB 111005A: EVLA Observations
  47. GRB 111005A: VLT optical observations
  48. GRB 111005A: GROND NIR observations
  49. GRB 111005A: VLT IR observations
  50. GRB 111005A: Swift-BAT refined analysis
  51. GRB 111005A: bright galaxy in error circle
  52. GRB 111005A: Swift detection of a burst
  53. GRB 111003A: Fermi GBM detection
  54. GRB 110905A / MAXI J1836-194: optical monitoring
  55. GRB 110921A: MITSuME-Akeno Optical photometry
  56. Skynet/Dolomiti observations of GRB 110928A
  57. Skynet observations of GRB 110928A
  58. GRB 110928A: RAPTOR Limits During Gamma-ray Emitting Interval
  59. GRB 110928A: Swift/UVOT Upper Limits
  60. Trigger 504307: Swift detection of MAXI J1836-194
  61. GRB 110928A: Swift-XRT refined Analysis
  62. GRB 110825A: GROND Observations
  63. GRB 110928A: Enhanced Swift-XRT position
  64. GRB 110928A: P60 Observations
  65. GRB 110928A: Further PAIRITEL NIR Observations
  66. GRB 110928A: Swift-BAT refined analysis
  67. GRB 110928A: Swift-XRT observations
  68. GRB 110928A: Swift/UVOT finding chart observation
  69. GRB 110928A: PAIRITEL NIR Observations
  70. GRB 110928A: ROTSE-III Optical Limits
  71. GRB 110928A: Swift detection of a burst
  72. Fermi GBM triggers 110923481, 110924391 and 110925200 are not GRBs
  73. Swift-BAT trigger 503926 is noise
  74. GRB 110924A: Swift detection of a possible burst
  75. GCN for GRB 110921B
  76. GRB 110921A: Swift/UVOT Observations
  77. GRB110918A: Lick Observations
  78. GRB 110921A: NOT observations
  79. GRB 110921A: Fermi GBM observation
  80. GRB 110921A: TNT astrometry
  81. GRB 110921A: Swift-XRT refined Analysis
  82. GRB 110921A, Swift-BAT refined analysis
  83. GRB 110918A: Liverpool Telescope optical observations
  84. GRB 110918A: submm observations from APEX
  85. GRB 110921A: optical observations in Mt. Terskol and Maidanak observatories
  86. GRB 110921A: Enhanced Swift-XRT position
  87. GRB 110921A: MITSuME Akeno Optical Observation
  88. GRB 110921A : TNT optical counterpart candidate
  89. GRB 110918A: Swift-XRT refined Analysis
  90. GRB 110918A: Spectroscopy from GTC
  91. GRB 110921A: MASTER-Net early limit
  92. GRB 110921A: Swift detection of a burst
  93. GRB 110915B : X-ray afterglow confirmation
  94. GRB 110918A: Swift/UVOT Detection of the Optical Counterpart
  95. GRB 110918A: rest-frame energetics in gamma-gays
  96. GRB 110918A optical observation
  97. GRB 110918A: Gemini-N redshift
  98. GRB 110918A: Afterglow Confirmation from PTF
  99. GRB 110918A: GROND detection of the afterglow candidate
  100. GRB 110918A: INT optical detection of Swift candidate afterglow

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