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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. IceCube-170321A: Konus-Wind upper limits
  2. Swift Trigger 745090 is a noise trigger near NGC 5195
  3. Fermi-LAT Gamma-ray Observations of IceCube-170321
  4. Swift triggered on SAX J1806.5-221
  5. GRB 170330A: AstroSat CZTI detection
  6. GRB 170330A: Swift-BAT refined analysis
  7. GRB 170331A: Swift-BAT refined analysis
  8. DOAO 1m telescope V, R, I observation of GRB 170317A
  9. GRB 170331A: Swift/UVOT Upper Limits
  10. IceCube-170321A: Swift-XRT observations
  11. GRB 170330A: Swift-XRT refined Analysis
  12. GRB 170331A: Swift-XRT refined Analysis
  13. GRB 170330A: Enhanced Swift-XRT position
  14. GRB 170331A: Enhanced Swift-XRT position
  15. GRB 170330A: Swift/UVOT Detection of a Fading Afterglow
  16. GRB 170325A: 15 GHz upper limits from AMI
  17. GRB 170318B: 15 GHz upper limits from AMI
  18. GRB 170318A: 15 GHz upper limits from AMI
  19. GRB 170317A: 15 GHz upper limits from AMI
  20. GRB 170330A: LCO Cerro Tololo observations
  21. LIGO/Virgo G275697: LOFAR follow-up
  22. Konus-Wind observation of GRB 170329A
  23. GRB 170329A: AstroSat CZTI detection
  24. IBAS trigger 7789 is not a GRB
  25. GRB 170331A: LCO Sutherland observations
  26. GRB 170331A: Prompt enhanced Swift-XRT position
  27. Fermi trigger 512347439/GRB 170327A: MASTER-SAAO possible OT detection
  28. GRB 170331A: Swift detection of a burst
  29. GRB 170330A: Prompt enhanced Swift-XRT position
  30. GRB 170330A: Swift detection of a burst
  31. GRB 170329A: Fermi GBM detection
  32. GRB 170329A: Fermi-LAT detection
  33. GRB 170325B: POLAR Observation
  34. GRB 170325A: Fermi GBM observation
  35. LIGO/Virgo G277583: Konus-Wind observations
  36. GRB 170325A, Swift-BAT detection of a short GRB
  37. INTEGRAL pointed follow-up of IceCube-170321A
  38. LIGO/Virgo G277583: Fermi GBM Observations
  39. Konus-Wind observation of GRB 170320A
  40. GRB 170320A: POLAR Observation
  41. LIGO/Virgo G277583: INTEGRAL search for an X-ray and gamma-ray counterpart
  42. Fermi GBM Observation of IceCube-170321A
  43. LIGO/Virgo G275697: AMI Large Array Search for a Radio Afterglow
  44. Fermi GBM trigger 511851891/170322212 is not a GRB
  45. IceCube-170321A - IceCube observation of a high-energy neutrino candidate event
  46. INTEGRAL SPI-ACS observation of AMON IceCube EHE 80305071 129307
  47. IPN Triangulation of GRB 170320A (long/intense)
  48. Search for counterpart to IceCube-170321A with ANTARES
  49. GRB 170318A: KAIT Optical Upper Limit
  50. GRB 170317A: Mondy optical observations
  51. GRB 170318B: Swift-BAT refined analysis
  52. GRB 170317A: POLAR observation
  53. GRB 170318B: RATIR Optical and NIR Observations
  54. GRB 170317A: RATIR Optical and NIR Observations
  55. GRB 170318B: Swift/UVOT Upper Limits
  56. GRB 170318B: Swift-XRT refined Analysis
  57. GRB 170318A: Swift-XRT refined Analysis
  58. LIGO/Virgo G277583: CALET Observations
  59. GRB 170318A: RATIR Optical and NIR Observations
  60. GRB 170318A: Swift/UVOT Upper Limits
  61. GRB 170318B: Fermi GBM observation
  62. GRB 170318A: Swift-BAT refined analysis
  63. GRB 170317A: RATIR Optical and NIR Observations
  64. GRB 170318B: Enhanced Swift-XRT position
  65. GRB 170318B: Prompt enhanced Swift-XRT position
  66. GRB 170318B: Swift detection of a burst
  67. GRB 170318A: Enhanced Swift-XRT position
  68. GRB 170315A: POLAR observation
  69. GRB 170318A: Prompt enhanced Swift-XRT position
  70. GRB 170318A: Swift detection of a burst
  71. IceCube-170312A: MASTER follow-up observations
  72. LIGO/Virgo G277583: Asiago spectroscopic classification of ATLAS17byo and ATLAS17cgg
  73. GRB 170317A: LCO FTN observations
  74. LIGO/Virgo G277583 : MAXI/GSC observations
  75. GRB 170317A: MITSuME Okayama Optical Observation
  76. LIGO/Virgo G275404: P200/DBSP Classification of iPTF Candidates
  77. LIGO/Virgo G277583: P200/DBSP Classification of ATLAS Candidates
  78. GRB 170317A: Swift-BAT refined analysis
  79. LIGO/Virgo G277583: AstroSat CZTI upper limits
  80. GRB 170317A: Swift/UVOT Detection
  81. GRB 170317A: Mondy optical observations
  82. GRB 170317A: MITSuME Okayama Ks-band upper-limit
  83. GRB 170317A: Swift-XRT refined Analysis
  84. IceCube-170312A: Swift-XRT observations
  85. GRB 170317A: GMG observation
  86. GRB 170317A : Xinglong TNT optical observation
  87. GRB 170317A: Enhanced Swift-XRT position
  88. GRB 170317A: ISON-Ussuriysk aferglow confirmation
  89. GRB 170317A: Swift detection of a burst with an optical counterpart
  90. LIGO/Virgo G275697: Swift-XRT source 23 no longer fading
  91. LIGO/Virgo G277583: Swift/BAT data search
  92. LIGO/Virgo G277583: Discovery Channel Telescope Follow-Up of ATLAS17cck
  93. SUBJECT: LIGO/Virgo G277583: ATLAS coverage and transients over the first 2 days
  94. GRB 170307A: 15 GHz upper limit from AMI
  95. LIGO/Virgo G277583: ATLAS17cck is likely a minor planet
  96. LIGO/Virgo G277583: GROND follow up of ATLAS17cck
  97. LIGO/Virgo G277583: ATLAS17cck - a fast declining transient
  98. LIGO/Virgo G275697: DLT40 follow-up observation
  99. LIGO/Virgo G274296: DLT40 follow-up observation
  100. LIGO/Virgo G275697: Fermi-LAT search for a high-energy gamma-ray counterpart

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