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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 151229A: MITSuME Okayama upper limits
  2. GRB 151229A Swift-BAT Spectral lag analysis
  3. LIGO/Virgo G211117: La Silla - QUEST observations 2015 Dec 28, 29
  4. GRB 151228B: MITSuME Akeno optical upper limits
  5. GRB 151229A: Swift-XRT refined Analysis
  6. GRB 151229A: Fermi GBM observation
  7. GRB 151228B: Fermi GBM observation
  8. GRB 151228A: Swift-BAT refined analysis
  9. GRB 151229A: Swift/UVOT observations
  10. GRB 151228B: Swift-BAT refined analysis
  11. GRB 151229A: Swift-BAT refined analysis
  12. GRB 151229A: Enhanced Swift-XRT position
  13. GRB 151228B: Swift-XRT refined Analysis
  14. LIGO/Virgo G211117: Further Swift-XRT sources
  15. GRB 151228A: MITSuME Akeno optical upper limits
  16. GRB 151228A: T60 observations
  17. GRB 151229A: Swift detection of a short burst
  18. LIGO/Virgo G211117: DESGW program observations with DECam
  19. GRB 151228B: Enhanced Swift-XRT position
  20. LIGO/Virgo G211117: Optical NIR observation with Kanata telescope
  21. LIGO/Virgo G211117: Fermi GBM Observations
  22. LIGO/Virgo G211117: Optical follow-up with Kanata telescope
  23. GRB 151228B: Swift detection of a burst with an optical detection
  24. LIGO/Virgo G211117: MASTER Observations and Inspection + OT
  25. LIGO/Virgo G211117: INTEGRAL was inactive at the time of the event
  26. GRB 151228A: Fermi GBM observation
  27. LIGO/Virgo G211117: Pan-STARRS1 observations 2015-12-28
  28. LIGO/Virgo G211117: INAF VST-ESO PARANAL observations
  29. LIGO/Virgo G211117: Further Swift-XRT sources
  30. LIGO/Virgo G211117: Swift-XRT sources
  31. GRB 151228A: Swift detection of a short burst
  32. LIGO/Virgo G211117: SWASP optical observations
  33. LIGO/Virgo G211117: MASTER possible OT detection at the begining of inspection
  34. LIGO/Virgo G211117: Identification of a GW CBC Candidate
  35. GRB 151227B: Fermi GBM detection
  36. GRB 151227A: Fermi GBM detection
  37. GRB 151212A iTelescope observation
  38. GRB 151225A: CALET Gamma-Ray Burst Monitor detection of a possible short GRB
  39. Konus-Wind observation of GRB 151222A
  40. Fermi GBM trigger 472694170/151224997 is not a GRB
  41. V404Cyg Swift Trigger 668097: TSHAO optical observations
  42. IPN Triangulation of GRB 151222A (short/hard)
  43. Fermi GBM trigger 151221730 is not a GRB
  44. V404Cyg Swift Trigger 668097: MASTER-Tunka optical wake up detection
  45. V404Cyg Swift Trigger 668097:
  46. Trigger 668097: Swift detection of V 404 Cyg
  47. GRB 151222A: Fermi GBM detection
  48. Fermi GBM trigger 151221690 is not a GRB
  49. Fermi GBM trigger 472271765/151220108 is not a GRB
  50. IBAS Alert 7313 is SGR J1935+2154
  51. GRB 151221A: INTEGRAL detection of a short burst or possible SGR
  52. Fermi GBM trigger 472166503/151218890 is not a GRB
  53. LIGO/Virgo G184098: Fermi-LAT search for high-energy gamma-ray counterpart
  54. GRB 151215A: TSHAO optical observations
  55. GRB151215A: Continued P60 Observations
  56. GRB 151212B: CALET Gamma-Ray Burst Monitor detection
  57. GRB 151216A: MAXI/GSC detection
  58. GRB 151210B: Fermi GBM observation
  59. GRB151215A: Early optical light curve from pt5m, La Palma
  60. GRB 151215A: MITSuME Akeno optical upper limits
  61. GRB 151210B: CALET Gamma-Ray Burst Monitor detection
  62. GRB 151215A: Swift-XRT refined Analysis
  63. GRB 151215A: Swift-BAT refined analysis
  64. GRB151215A: Swift/UVOT detection
  65. GRB 151215A: MASTER early OT detection and light curve
  66. GRB 151215A: NOT spectroscopy and redshift
  67. GRB 151215A: Enhanced Swift-XRT position
  68. GRB 151215A: GROND Detection of the Optical/NIR Afterglow
  69. GRB 151215A: Prompt enhanced Swift-XRT position
  70. GRB151215A: P60 Optical Afterglow Candidate
  71. GRB 151215A: Swift detection of a burst
  72. LIGO/Virgo G184098: LOFAR follow-up
  73. GRB151212A: Swift/UVOT observations
  74. GRB 151212A: GROND Optical Afterglow Candidate
  75. GRB 151212A: Swift-XRT afterglow detection
  76. GRB 151212A: Tiled Swift observations
  77. GRB 151212A: MAXI/GSC detection
  78. GRB 151210A: Swift/UVOT Upper Limits
  79. GRB 151210A: Swift-BAT refined analysis
  80. GRB 151210A: Swift-XRT refined Analysis
  81. GRB 151210A: Enhanced Swift-XRT position
  82. GRB 151210A: GROND Afterglow Confirmation
  83. GRB 151210A: Optical afterglow candidate from LCOGT-Cerro Tololo
  84. GRB 151210A: Swift detection of a burst
  85. GRB 151205C: Optical follow-up observations at Kiso
  86. GRB 151205A: Khureltogot upper limit
  87. Swift detection of 4U 1850-03
  88. GRB 151205B: Deep GROND Upper limits
  89. GRB 130831A: MASTER early OT detection and LC
  90. GRB 151205B: further Swift-XRT observations
  91. GRB 151205C: Swift-XRT observations
  92. GRB 151205B, Swift-BAT refined analysis
  93. GRB 151205A: Swift-XRT refined Analysis
  94. GRB 151205A, Swift-BAT refined analysis
  95. GRB 151205C: Tiled Swift observations
  96. GRB 151205C: MAXI/GSC detection
  97. GRB 151205B: MASTER-NET early optical observations
  98. GRB 151205A: Fermi GBM detection
  99. GRB 151205A: Garching Telescope Upper Limit
  100. GRB151205B: Initial UVOT observations

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