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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 170330A: Swift/UVOT Detection of a Fading Afterglow
  2. GRB 170325A: 15 GHz upper limits from AMI
  3. GRB 170318B: 15 GHz upper limits from AMI
  4. GRB 170318A: 15 GHz upper limits from AMI
  5. GRB 170317A: 15 GHz upper limits from AMI
  6. GRB 170330A: LCO Cerro Tololo observations
  7. LIGO/Virgo G275697: LOFAR follow-up
  8. Konus-Wind observation of GRB 170329A
  9. GRB 170329A: AstroSat CZTI detection
  10. IBAS trigger 7789 is not a GRB
  11. GRB 170331A: LCO Sutherland observations
  12. GRB 170331A: Prompt enhanced Swift-XRT position
  13. Fermi trigger 512347439/GRB 170327A: MASTER-SAAO possible OT detection
  14. GRB 170331A: Swift detection of a burst
  15. GRB 170330A: Prompt enhanced Swift-XRT position
  16. GRB 170330A: Swift detection of a burst
  17. GRB 170329A: Fermi GBM detection
  18. GRB 170329A: Fermi-LAT detection
  19. GRB 170325B: POLAR Observation
  20. GRB 170325A: Fermi GBM observation
  21. LIGO/Virgo G277583: Konus-Wind observations
  22. GRB 170325A, Swift-BAT detection of a short GRB
  23. INTEGRAL pointed follow-up of IceCube-170321A
  24. LIGO/Virgo G277583: Fermi GBM Observations
  25. Konus-Wind observation of GRB 170320A
  26. GRB 170320A: POLAR Observation
  27. LIGO/Virgo G277583: INTEGRAL search for an X-ray and gamma-ray counterpart
  28. Fermi GBM Observation of IceCube-170321A
  29. LIGO/Virgo G275697: AMI Large Array Search for a Radio Afterglow
  30. Fermi GBM trigger 511851891/170322212 is not a GRB
  31. IceCube-170321A - IceCube observation of a high-energy neutrino candidate event
  32. INTEGRAL SPI-ACS observation of AMON IceCube EHE 80305071 129307
  33. IPN Triangulation of GRB 170320A (long/intense)
  34. Search for counterpart to IceCube-170321A with ANTARES
  35. GRB 170318A: KAIT Optical Upper Limit
  36. GRB 170317A: Mondy optical observations
  37. GRB 170318B: Swift-BAT refined analysis
  38. GRB 170317A: POLAR observation
  39. GRB 170318B: RATIR Optical and NIR Observations
  40. GRB 170317A: RATIR Optical and NIR Observations
  41. GRB 170318B: Swift/UVOT Upper Limits
  42. GRB 170318B: Swift-XRT refined Analysis
  43. GRB 170318A: Swift-XRT refined Analysis
  44. LIGO/Virgo G277583: CALET Observations
  45. GRB 170318A: RATIR Optical and NIR Observations
  46. GRB 170318A: Swift/UVOT Upper Limits
  47. GRB 170318B: Fermi GBM observation
  48. GRB 170318A: Swift-BAT refined analysis
  49. GRB 170317A: RATIR Optical and NIR Observations
  50. GRB 170318B: Enhanced Swift-XRT position
  51. GRB 170318B: Prompt enhanced Swift-XRT position
  52. GRB 170318B: Swift detection of a burst
  53. GRB 170318A: Enhanced Swift-XRT position
  54. GRB 170315A: POLAR observation
  55. GRB 170318A: Prompt enhanced Swift-XRT position
  56. GRB 170318A: Swift detection of a burst
  57. IceCube-170312A: MASTER follow-up observations
  58. LIGO/Virgo G277583: Asiago spectroscopic classification of ATLAS17byo and ATLAS17cgg
  59. GRB 170317A: LCO FTN observations
  60. LIGO/Virgo G277583 : MAXI/GSC observations
  61. GRB 170317A: MITSuME Okayama Optical Observation
  62. LIGO/Virgo G275404: P200/DBSP Classification of iPTF Candidates
  63. LIGO/Virgo G277583: P200/DBSP Classification of ATLAS Candidates
  64. GRB 170317A: Swift-BAT refined analysis
  65. LIGO/Virgo G277583: AstroSat CZTI upper limits
  66. GRB 170317A: Swift/UVOT Detection
  67. GRB 170317A: Mondy optical observations
  68. GRB 170317A: MITSuME Okayama Ks-band upper-limit
  69. GRB 170317A: Swift-XRT refined Analysis
  70. IceCube-170312A: Swift-XRT observations
  71. GRB 170317A: GMG observation
  72. GRB 170317A : Xinglong TNT optical observation
  73. GRB 170317A: Enhanced Swift-XRT position
  74. GRB 170317A: ISON-Ussuriysk aferglow confirmation
  75. GRB 170317A: Swift detection of a burst with an optical counterpart
  76. LIGO/Virgo G275697: Swift-XRT source 23 no longer fading
  77. LIGO/Virgo G277583: Swift/BAT data search
  78. LIGO/Virgo G277583: Discovery Channel Telescope Follow-Up of ATLAS17cck
  79. LIGO/Virgo G277583: ATLAS coverage and transients over the first 2 days
  80. GRB 170307A: 15 GHz upper limit from AMI
  81. LIGO/Virgo G277583: ATLAS17cck is likely a minor planet
  82. LIGO/Virgo G277583: GROND follow up of ATLAS17cck
  83. LIGO/Virgo G277583: ATLAS17cck - a fast declining transient
  84. LIGO/Virgo G275697: DLT40 follow-up observation
  85. LIGO/Virgo G274296: DLT40 follow-up observation
  86. LIGO/Virgo G275697: Fermi-LAT search for a high-energy gamma-ray counterpart
  87. LIGO/Virgo G277583: ERRATUM LV GCN 20871: TAROT Calern (TCA) observations
  88. GRB 170311B: AstroSat CZTI detection
  89. LIGO/Virgo G277583: TAROT Calern (TCA) observations
  90. LIGO/Virgo G277583: SVOM/Mini-GWAC observations of the initial skymap
  91. LIGO/Virgo G275404: Medicina radio follow-up of near-infrared
  92. Fermi GBM trigger 510642159/170308210 is not a GRB
  93. LIGO/Virgo G277583: INTEGRAL was inactive at the time of the event
  94. LIGO/Virgo G277583 ANTARES search
  95. Konus-Wind observation of GRB 170311B
  96. LIGO/Virgo G277583: AGILE GRID observations
  97. LIGO/Virgo G277583: AGILE MCAL observations
  98. LIGO/Virgo G270580: optical observations and classification of PS and MASTER sources
  99. LIGO/Virgo G277583: IceCube neutrino observations
  100. LIGO/Virgo G277583: Identification of a GW Burst Candidate

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