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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. Search for counterparts to IceCube-190124A with IceCube
  2. Search for counterpart to IceCube-190124A with ANTARES
  3. GRB 190117A: AstroSat CZTI detection
  4. GRB 190122B: AstroSat CZTI detection
  5. Fermi-LAT Gamma-ray Observations of IceCube-190124A
  6. GRB 190123A: IKI-GRB-FuN optical upper limit
  7. GRB 190123A: NEXT-0.6m optical limit
  8. GRB 190114C: CHILESCOPE optical observations
  9. GRB 190123A: AROMA-N Optical Observation
  10. IceCube-190124A - IceCube observation of a high-energy neutrino candidate event
  11. GRB 190123A: Swift/UVOT Upper Limits
  12. Konus-Wind observation of GRB 190122A
  13. Konus-Wind of observation of GRB 190117A
  14. GRB 190123A: COATLI Optical Observations
  15. GRB 190123A: Swift-BAT refined analysis
  16. GRB 190121A: CALET Gamma-Ray Burst Monitor detection of a short burst
  17. GRB190123A: MITSuME Akeno optical upper limits
  18. GRB 190123A: GMG observational limit
  19. Trigger 885456: Swift detection of MAXI J1631-479
  20. GRB 190123A: Swift-XRT refined Analysis
  21. GRB 190123A: GOTO optical limit
  22. GRB 190123A: Fermi GBM observation
  23. GRB 190123A: BOOTES-4/MET optical limit
  24. GRB 190123A: Enhanced Swift-XRT position
  25. GRB 190123A: MASTER Global Robotic Net optical observation
  26. GRB 190123A: Swift detection of a burst
  27. GRB 190122A: Fermi GBM observation
  28. GRB 190122A: Fermi-LAT detection
  29. GRB 190114C: RTT150 optical observations
  30. IPN Triangulation of GRB 190118A (long)
  31. IPN Triangulation of GRB 190117A (long)
  32. Trigger 884906: Swift detection of MAXI J1631-479
  33. GRB 190114C: GMRT detection at 1.26GHz
  34. Swift ToO Instructions Update
  35. GRB 190114C: MeerKAT radio observation
  36. GRB 190117A: Insight-HXMT/HE detection
  37. Swift ToO Website Down
  38. GRB 190114C: UKIRT JHK observation (CORRECTIONS)
  39. GRB 190114C: UKIRT JHK observation continuation - steady fading?
  40. GRB 190114C: Sardinia Radio Telescope observations (CORRECTION)
  41. GRB 190114C: REM optical/NIR detection (CORRECTION)
  42. GRB 190114C: Sardinia Radio Telescope observations
  43. GRB 190117A: AGILE/MCAL detection of a burst
  44. GRB 190114C: RATIR Optical and NIR Detections
  45. GRB 190114C: RT-22 detection at 36.8 GHz
  46. GRB 190114C: COATLI Optical Detection
  47. GRB 190114C: ePESSTO NTT optical observations
  48. GRB 190114C: Continued UKIRT JHK observation
  49. GRB 190114C: continued CHILESCOPE optical obs
  50. GRB190114C: ATCA detection of the radio afterglow
  51. GRB 190106A: Discovery Channel Telescope observations
  52. GRB 190114B: continued optical observations in Mondy
  53. GRB 190114C: Optical detection from HCT
  54. GRB 190114C: CHILESCOPE optical observations
  55. GRB 190114C: UKIRT JHK observation
  56. GRB 190114A: NOEMA detection of the mm afterglow
  57. GRB 190114A:DOAO/LOAO optical observation
  58. Konus-Wind observation of GRB 190114C
  59. The Swift-XRT WT mode spectrum of GRB190114C
  60. GRB190114C, Long follow up urged
  61. GRB 190114C: KMTNet optical observation
  62. GRB190114C: GRowth-India detection of optical afterglow
  63. GRB 190114C: LSGT optical observation
  64. GRB 190114A: DOAO/LOAO optical observation
  65. GRB 190114B: Swift-XRT refined Analysis
  66. GRB 190114C: REM optical/NIR detection
  67. GRB 190114C: ALMA detection of a fading mm counterpart
  68. GRB 190114C: Mondy optical observations
  69. GRB 190114C: VLA Detection
  70. GRB 190114C: Swift/UVOT Detection
  71. GRB 190114C: Swift-BAT refined analysis
  72. GRB 190114B: Liverpool Telescope near-IR observations
  73. GRB 190114B: optical afterglow observations in Mondy and Abastumani observatories
  74. GRB 190114B, Swift-BAT refined analysis
  75. GRB 190114B: Swift/UVOT Upper Limits
  76. GRB 190114A: Swift/UVOT Observations
  77. GRB 190114A: Mondy optical afterglow detectio
  78. GRB 190114C: Optical observations
  79. GRB 190114C:Insight-HXMT/HE detection
  80. GRB 190114C: A type 1 BdHN with TeV emission
  81. GRB 190114C: SPI-ACS/INTEGRAL extended emission detection
  82. GRB 190114B: NOT optical counterpart
  83. GRB 190114C: AGILE/MCAL detection
  84. GRB190109B: MITSuME Akeno optical upper limits
  85. GRB 190114C: X-shooter observations of a highly extinguished afterglow
  86. GRB 190114C: Fermi-LAT detection
  87. GRB 190114C: refined redshift by the 10.4m GTC
  88. GRB 190114C: Fermi GBM detection
  89. GRB 190114C: Swift-XRT refined Analysis
  90. GRB 190114B: MITSuME Akeno optical upper limits
  91. GRB 190114C: Enhanced Swift-XRT position
  92. GRB 190114B: GWAC-F60B upper limit
  93. GRB 190114C: GROND detection of the afterglow
  94. MAGIC detects the GRB 190114C in the TeV energy domain
  95. CORRECTED TARGET NAME: GRB 190114C: Planned XMM-Newton observation
  96. GRB 190114C: OASDG optical observations
  97. GRB 150114C#: Planned XMM-Newton observation
  98. GRB 190114A: NOT optical observations
  99. GRB 190114B: Mondy optical afterglow detection
  100. GRB 190114C: NOT optical counterpart and redshift

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