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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 171205A: VLT/X-shooter optical counterpart and spectroscopic observations
  2. GRB 171205A: Enhanced Swift-XRT position
  3. GRB 171205A: Likely association with low-z spiral galaxy
  4. GRB 171205A: Swift detection of a burst
  5. GRB 171126A: AstroSat CZTI detection
  6. GRB 171124A: TShAO optical observations
  7. GRB 171124A: Swift-XRT afterglow detection
  8. Pan-STARRS follow-up of IceCube-171106A
  9. LIGO/Virgo G299232: LOFAR follow-up
  10. GRB 171124A: Insight-HXMT/HE detection
  11. GRB 171126A: Fermi GBM detection
  12. GRB 171123A: TShAO optical upper limit
  13. GRB 171124A: AstroSat CZTI detection
  14. INTEGRAL pointed follow-up of IceCube-171106A
  15. GRB 171123A: OSN Upper Limit
  16. GRB 171124A: Swift-XRT observations
  17. GRB 171124A: Fermi GBM observation
  18. GRB 171119A: AstroSat CZTI detection
  19. GRB 171123A: Tautenburg observations
  20. GRB 171123A: Nanshan-1m optical upper limit
  21. GRB 171123A: RATIR Optical and NIR Observations
  22. GRB 171124A: MITSuME Akeno optical upper limits
  23. GRB 171123A: Swift/UVOT Upper Limits
  24. GRB 171123A: GMG observation limit
  25. GRB 171124A: Fermi-LAT detection
  26. GRB 171124A: Swift ToO observations
  27. GRB 171123A: MITSuME Akeno optical upper limits
  28. GRB 171123A: Swift-BAT refined analysis
  29. GRB 171123A: Swift-XRT refined Analysis
  30. GRB 171123A: Confirmation of the X-ray afterglow
  31. GRB 171123A: Enhanced Swift-XRT position
  32. GRB 171120A: Insight-HXMT detection
  33. GRB 171123A: Swift detection of a burst
  34. Konus-Wind observation of GRB 171119A
  35. IPN Triangulation of GRB 171119A (long)
  36. GRB 171120A: Xinglong-2.16m optical upper limit
  37. GRB 171120A: Swift/UVOT Upper Limits
  38. GRB 171120A: AstroSat CZTI detection
  39. Konus-Wind observation of GRB 171120A
  40. GRB171120A: GWAC-F60A upper limit
  41. GRB 171120A: MITSuME Akeno optical upper limits
  42. GRB 171120A: Swift-BAT refined analysis
  43. GRB 171120A: Fermi GBM Detection
  44. GRB 171120A: Swift-XRT refined Analysis
  45. GRB 171120A: Fermi-LAT detection
  46. GRB 171120A: Enhanced Swift-XRT position
  47. GRB 171115B: Insight-HXMT detection
  48. GRB 171120A: Swift detection of a burst
  49. Fermi-LAT Gamma-ray Observations of IceCube-171106A
  50. GRB 171108B: Insight-HXMT detection
  51. GRB 171115A: RATIR Optical and NIR Observations
  52. GRB 171115A: MITSuME Okayama optical upper limits
  53. GRB 171115A: MITSuME Akeno optical upper limits
  54. GRB 171115A: Swift-BAT refined analysis
  55. GRB 171115A: Swift-XRT refined Analysis
  56. GRB 171115A: Enhanced Swift-XRT position
  57. GRB 171115A: Swift detection of a burst
  58. GRB 171112A: Fermi GBM Detection
  59. LIGO/Virgo G288732/GW170608: updated localization from parameter estimation
  60. Konus-Wind observation of GRB 171112A
  61. FACT follow-up of IceCube20171106
  62. Konus-Wind observation of GRB 171108A
  63. GRB 171112A: MAXI/GSC detection
  64. IPN Triangulation of GRB 171108A (short)
  65. GRB 171103A: Insight-HXMT observation
  66. IceCube-171106A: Swift Observations
  67. HAWC follow-up of IceCube-171106A
  68. GRB 171010A: afterglow and SN 2017htp optical observations
  69. GRB 171108A: Fermi GBM detection
  70. GRB 171102A CALET Gamma-Ray Burst Monitor detection
  71. GRB 171101A CALET Gamma-Ray Burst Monitor detection
  72. INTEGRAL observation of IceCube-171106A
  73. GRB 171030A: MASTER OT J034412.48-263556.5 featureless continuum spectrum from Lijiang 2.4m (China) telescope and 2m the Himalayan Chandra
  74. GRB 171010A: possible SN component
  75. Fermi-GBM Trigger 531686417 / 171106778 is not related to ICECUBE-171106A
  76. IceCube-171106A - IceCube observation of a high-energy neutrino candidate
  77. AMON ICECUBE EHE 130214 (close by time to Fermi trigger): MASTER early follow-up observations
  78. GRB 171103A: AstroSat CZTI detection
  79. GRB 171030A: MASTER inspection of the IPN error box of the short GRB.
  80. Konus-Wind observation of GRB 171103A (short/hard)
  81. GRB 171103A: Fermi GBM observation
  82. GRB 171103A: Swift-BAT refined analysis of a short GRB
  83. LIGO/Virgo G298936: NOT spectroscopy of GWFUNC-17ure
  84. Fermi GBM detections of Swift J0243.6+6124 and modification of the GBM trigger configuration
  85. GRB 171010A: VLT spectroscopic identification of the associated SN 2017htp
  86. GRB 171103A: Swift detection of a short hard burst
  87. Konus-Wind observation of GRB 171102A
  88. GRB 171102B: AbAO optical upper limit
  89. GRB 171102B: TShAO optical upper limit
  90. IPN Triangulation of GRB 171102A
  91. GRB 171102B: Nanshan 0.36m and 0.60m optical upper limits
  92. GRB 171102B: RATIR Optical and NIR Observations
  93. GRB 171102B: Swift-BAT refined analysis
  94. GRB 171102B: MITSuME Akeno optical upper limits
  95. GRB 171102B: Swift/UVOT Upper Limits
  96. GRB 171102B: Swift-XRT refined Analysis
  97. GRB 171102B: Enhanced Swift-XRT position
  98. GRB 171102A: Fermi GBM detection
  99. GRB 171102B: Swift detection of a burst
  100. GRB 171102A: Fermi-LAT detection

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