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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. Swift Trigger 796098 is probably a noise peak near M31
  2. LIGO/Virgo GW170817: X-ray observations confirm prediction made from radio data
  3. GRB 171124A CALET Gamma-Ray Burst Monitor detection
  4. GRB 171120A CALET Gamma-Ray Burst Monitor detection
  5. GRB 171106A CALET Gamma-Ray Burst Monitor detection
  6. LIGO/Virgo GW170817: Further Hubble Space Telescope observations
  7. LIGO/Virgo G298048: Brightening X-ray Emission from GW170817/GRB170817A/SSS17a
  8. GRB 171205A: TSHAO optical observations
  9. GRB 171205A: Detection of the emerging SN
  10. LIGO/Virgo GW170817: Chandra X-ray brightening of the counterpart 108 days since merger
  11. GRB 171205A: Continued Swift/UVOT Observations
  12. LIGO/Virgo G298048: Late-time detection of the X-ray afterglow with Chandra
  13. Fermi GBM trigger 534174346/171205573 is not a GRB
  14. GRB 171205A: MASTER-SAAO optical observations of unusual OT
  15. GRB 171205A: GROND observations of the optical/NIR transient
  16. GRB 171205A: LCO 1-m telescope observations
  17. GRB171205A hyperluminal radio afterglow?
  18. GRB 171205A: GMG observations (2nd night)
  19. GRB 171205A: Host galaxy photometric properties
  20. GRB 171205A: CHILESCOPE optical observations
  21. GRB 171205A: SMARTS optical/IR afterglow observations
  22. Possible blackbody component in the X-ray spectrum of GRB171205A
  23. GRB 171205A: GOTO detection of the optical counterpart
  24. GRB 171205A: TNG NIR detections
  25. GRB 171205A: LSGT optical afterglow follow-up observation
  26. GRB 171205A: NOEMA detection of a bright mm afterglow
  27. GRB 171205A: GMG observation
  28. Fermi Gamma-ray Burst Monitor trigger 534174346/171205573 is not a GRB
  29. GRB 171205A: Swift-BAT refined analysis
  30. GRB 171205A: Swift-XRT refined Analysis
  31. GRB 171205A: RATIR Optical and NIR Observations
  32. GRB 171205A: Swift/UVOT Detection
  33. GRB 171205A: VLT/X-shooter optical counterpart and spectroscopic observations
  34. GRB 171205A: Enhanced Swift-XRT position
  35. GRB 171205A: Likely association with low-z spiral galaxy
  36. GRB 171205A: Swift detection of a burst
  37. GRB 171126A: AstroSat CZTI detection
  38. GRB 171124A: TShAO optical observations
  39. GRB 171124A: Swift-XRT afterglow detection
  40. Pan-STARRS follow-up of IceCube-171106A
  41. LIGO/Virgo G299232: LOFAR follow-up
  42. GRB 171124A: Insight-HXMT/HE detection
  43. GRB 171126A: Fermi GBM detection
  44. GRB 171123A: TShAO optical upper limit
  45. GRB 171124A: AstroSat CZTI detection
  46. INTEGRAL pointed follow-up of IceCube-171106A
  47. GRB 171123A: OSN Upper Limit
  48. GRB 171124A: Swift-XRT observations
  49. GRB 171124A: Fermi GBM observation
  50. GRB 171119A: AstroSat CZTI detection
  51. GRB 171123A: Tautenburg observations
  52. GRB 171123A: Nanshan-1m optical upper limit
  53. GRB 171123A: RATIR Optical and NIR Observations
  54. GRB 171124A: MITSuME Akeno optical upper limits
  55. GRB 171123A: Swift/UVOT Upper Limits
  56. GRB 171123A: GMG observation limit
  57. GRB 171124A: Fermi-LAT detection
  58. GRB 171124A: Swift ToO observations
  59. GRB 171123A: MITSuME Akeno optical upper limits
  60. GRB 171123A: Swift-BAT refined analysis
  61. GRB 171123A: Swift-XRT refined Analysis
  62. GRB 171123A: Confirmation of the X-ray afterglow
  63. GRB 171123A: Enhanced Swift-XRT position
  64. GRB 171120A: Insight-HXMT detection
  65. GRB 171123A: Swift detection of a burst
  66. Konus-Wind observation of GRB 171119A
  67. IPN Triangulation of GRB 171119A (long)
  68. GRB 171120A: Xinglong-2.16m optical upper limit
  69. GRB 171120A: Swift/UVOT Upper Limits
  70. GRB 171120A: AstroSat CZTI detection
  71. Konus-Wind observation of GRB 171120A
  72. GRB171120A: GWAC-F60A upper limit
  73. GRB 171120A: MITSuME Akeno optical upper limits
  74. GRB 171120A: Swift-BAT refined analysis
  75. GRB 171120A: Fermi GBM Detection
  76. GRB 171120A: Swift-XRT refined Analysis
  77. GRB 171120A: Fermi-LAT detection
  78. GRB 171120A: Enhanced Swift-XRT position
  79. GRB 171115B: Insight-HXMT detection
  80. GRB 171120A: Swift detection of a burst
  81. Fermi-LAT Gamma-ray Observations of IceCube-171106A
  82. GRB 171108B: Insight-HXMT detection
  83. GRB 171115A: RATIR Optical and NIR Observations
  84. GRB 171115A: MITSuME Okayama optical upper limits
  85. GRB 171115A: MITSuME Akeno optical upper limits
  86. GRB 171115A: Swift-BAT refined analysis
  87. GRB 171115A: Swift-XRT refined Analysis
  88. GRB 171115A: Enhanced Swift-XRT position
  89. GRB 171115A: Swift detection of a burst
  90. GRB 171112A: Fermi GBM Detection
  91. LIGO/Virgo G288732/GW170608: updated localization from parameter estimation
  92. Konus-Wind observation of GRB 171112A
  93. FACT follow-up of IceCube20171106
  94. Konus-Wind observation of GRB 171108A
  95. GRB 171112A: MAXI/GSC detection
  96. IPN Triangulation of GRB 171108A (short)
  97. GRB 171103A: Insight-HXMT observation
  98. IceCube-171106A: Swift Observations
  99. HAWC follow-up of IceCube-171106A
  100. GRB 171010A: afterglow and SN 2017htp optical observations

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