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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 160506A: Swift-XRT refined Analysis
  2. GRB 160506A: Swift/UVOT Upper Limits
  3. GRB 160506A: Swift-BAT refined analysis
  4. GRB 160506A: GROND upper limits
  5. GRB 160506A: Enhanced Swift-XRT position
  6. GRB 160506A: Swift detection of a burst
  7. GRB 160504A: Swift-BAT refined analysis
  8. IceCube-160427A: iPTF Observations
  9. GRB 160504A: RATIR Optical and NIR Observations
  10. GRB 160504A: Swift/UVOT Upper Limits
  11. GRB160504A: Gemini NIR Observations
  12. GRB 160504A: Bassano Bresciano Observatory upper limits
  13. GRB 160504A: Swift-XRT refined Analysis
  14. GRB 160504A: Enhanced Swift-XRT position
  15. GRB 160504A: NOT upper limits
  16. GRB 160417A, the review of the sky area in plate archive
  17. GRB 160504A: TAROT Calern observatory optical observations
  18. GRB 160504A: Swift detection of a burst
  19. ICECUBE-160427A : Pan-STARRS imaging and optical transients in the field
  20. GRB 160503A: Fermi GBM observation
  21. GRB 160503A: Fermi-LAT detection
  22. GRB 160501A: SMARTS optical/IR observations
  23. VERITAS rapid follow-up observations of IceCube event 160427A
  24. GRB 160501A: Swift-BAT refined analysis
  25. GRB 160501A: GROND Upper limits
  26. GRB 160501A: MITSuME Okayama upper limits
  27. GRB 160501A: UKIRT near-IR upper limits
  28. GRB 160501A: Swift/UVOT Upper Limits
  29. GRB 160501A: Swift-XRT refined Analysis
  30. GRB 160501A: RATIR Optical and NIR Observations
  31. GRB 160501A: Enhanced Swift-XRT position
  32. GRB 160501A: TAROT Calern observatory optical observations
  33. GRB 160501A MASTER-NET early observations
  34. GRB 160501A: NOT optical and NIR observations
  35. GRB 160501A: Swift detection of a burst
  36. IceCube-160427A: Fermi GBM Observations
  37. ICECUBE-160427A neutrino candidate event: updated direction information
  38. MASTER search for counterpart to the IceCube event 67093193 (run 127853)
  39. Archival observations by HAWC of IceCube HESE event of April 27, 2016
  40. Fermi/LAT search for counterpart to the IceCube event 67093193 (run 127853)
  41. GRB 160422A: XRT Afterglow Confirmation
  42. LSGT observation of GRB 160425A
  43. GRB 160425A: Swift/UVOT Detection
  44. GRB 160425A: Skynet PROMPT-CTIO observations of the optical afterglow
  45. GRB 160425A: Swift-BAT refined analysis
  46. GRB 160425A: SMARTS optical/IR observations
  47. GRB 160325A: Skynet PROMPT-CTIO observations of the optical afterglow
  48. GRB 160422A: GROND NIR afterglow detection
  49. GRB 160425A MASTER notices: possible host galaxy in the optical error-box
  50. GRB 160425A VLT/X-shooter redshift
  51. GRB 160425A: GROND observation
  52. GRB 160425A: Swift-XRT refined Analysis
  53. GRB 160425A: Enhanced Swift-XRT position
  54. GRB 160422A: Swift/UVOT Afterglow Confirmation
  55. GRB 160422A: CALET Gamma-Ray Burst Monitor detection
  56. GRB 160425A : MASTER earlier optical observations
  57. GRB 160425A: Swift detection of an unusual burst with an optical afterglow
  58. Konus-Wind observation of GRB 160424A
  59. LIGO/Virgo G197392 / LVT151012: Identification of a GW CBC Candidate
  60. GRB 160424A: Fermi GBM observation
  61. GRB 160424A - XRT position uncertain
  62. GRB 160424A: Swift-BAT refined analysis
  63. GRB 160424A: Swift/UVOT Upper Limit
  64. GRB 160424A: Swift-XRT observations
  65. GRB 160424A: Swift detection of a burst
  66. GRB 160422A: Swift-XRT afterglow detection
  67. GRB 160422A: Swift/UVOT Candidate Afterglow
  68. GRB 160419A: CALET Gamma-Ray Burst Monitor detection
  69. GRB 160422A: Fermi GBM observation
  70. GRB 160422A: Swift ToO observations
  71. GRB 160422A: Fermi-LAT Detection
  72. GRB 160419A, Swift-BAT refined analysis
  73. GRB 160419A: Fermi GBM detection
  74. GRB 160419A: Swift detection of a burst
  75. Fermi GBM trigger 482632364/160418023 is not a GRB
  76. GRB 160417A: GMG observations
  77. GRB 160417A: Swift-BAT refined analysis
  78. GRB 160417A: Swift/UVOT Detection
  79. GRB 160417A: iTelescope T11 optical observations
  80. GRB 160417A: Swift-XRT refined Analysis
  81. GRB 160417A: MITSuME Okayama upper limits
  82. GRB 160417A: Enhanced Swift-XRT position
  83. GRB 160417A: KAIT optical afterglow confirmation
  84. GRB 160417A: Swift detection of a burst with an optical counterpart
  85. LIGO/Virgo G211117: EWE for NOWT of 12 days follow-up of northern sky
  86. GRB 160412A: GROND upper limits
  87. GRB 160411A - Gemini-S afterglow candidate
  88. Konus-Wind observation of GRB 160409A
  89. GRB 160410A: SMARTS optical/IR observations
  90. LIGO Virgo G211117: Additional MWA Observations
  91. GRB 160410A: TLS Tautenburg observations
  92. GRB 160412A: Swift/UVOT Upper Limits
  93. Swift Trigger 682614 is not a GRB
  94. GRB 160410A: JCMT SCUBA-2 sub-mm observation
  95. GRB 160409A: Swift-XRT observations
  96. GRB 160409A found in Swift BAT ground analysis
  97. GRB 160412A: Swift-XRT refined Analysis
  98. GRB 160411A: Swift-BAT refined analysis of the short burst
  99. GRB 160412A: Swift-BAT refined analysis
  100. GRB 160410A: further NOT optical observations

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