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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"

28718 results found.

  1. GRB 200826A: AGILE detection
  2. GRB 200826A: AstroSat CZTI detection
  3. GRB 200826A: Fermi GBM observation
  4. Fermi GRB 200826A: Global MASTER-Net observations report
  5. Swift Trigger 992444 is due to detector noise
  6. GRB 200819A: Swift/UVOT Upper Limits
  7. IceCube-200806A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  8. Konus-Wind observation of GRB 200815A
  9. GRB 200819A: Swift-BAT refined analysis
  10. GRB 200815A: MASTER optical observations
  11. IPN triangulation of GRB 200815A (short)
  12. GRB 200819A: Optical Observations from HCT
  13. GRB 200819A: Swift-XRT refined Analysis
  14. GRB 200819A: MITSuME Ishigaki optical upper limits
  15. GRB 200729A: Lowell Discovery Telescope observations
  16. GRB 200819A: MITSuME Akeno optical upper limits
  17. GRB 200819A: Kitab, TSHAO optical upper limit
  18. Swift GRB 200819A: Global MASTER-Net observations report
  19. Swift Trigger 990358 is due to detector noise
  20. Swift Trigger 989458 is due to detector noise
  21. Fermi GRB 200817A: Global MASTER-Net observations report
  22. GRB 200815A: CALET Gamma-Ray Burst Monitor detection of a short burst
  23. Alert from the HAWC Burst Monitor HAWC-200814A
  24. IceCube200806A: No significant detection in HAWC
  25. GRB 200809B: Fermi GBM detection
  26. Fermi GRB 200809B: Global MASTER-Net observations report
  27. GRB 200809B: Swift-XRT afterglow detection
  28. GRB 200809B: MAXI/GSC detection
  29. GRB 200809B: Swift ToO observations
  30. GRB 200809B: AstroSat CZTI detection
  31. GRB 200809B: Swift/BAT-GUANO detection and arcminute localization
  32. GRB 200808A: AGILE detection
  33. GRB 200806A: CALET Gamma-Ray Burst Monitor detection
  34. Fermi GRB 200808A: Global MASTER-Net observations report
  35. GRB 200806A: Nanshan/NEXT optical upper limit
  36. IPN triangulation of GRB 200805A (short)
  37. GRB 200806A: CAHA optical afterglow confirmation
  38. GRB 200803A: Chilescope optical upper limit
  39. GRB 200806A: VIRT optical observations
  40. GRB 200806A: Swift-BAT refined analysis
  41. GRB 200806A: Swift/UVOT Possible Detection
  42. GRB 200806A: Swift-XRT refined Analysis
  43. Fermi-LAT Gamma-ray Observations of IceCube-200806A
  44. CGBM-SPI-ACS triangulation of short GRB 200805A
  45. GRB 200806A: AbAO optical upper limit
  46. GRB 200805A: CALET Gamma-Ray Burst Monitor detection of a short burst
  47. GRB 200806A: AstroSat CZTI detection
  48. GRB 200806A: MITSuME Akeno optical upper limits
  49. IceCube-200806A: Upper limits from Fermi-GBM Observations
  50. Swift GRB 200806A: Global MASTER-Net observations report
  51. GRB 200803B: MASTER possibly OT discovery
  52. GRB 200803A: AstroSat CZTI detection
  53. GRB 200803A: Fermi GBM detection
  54. GRB 200803A: Swift-XRT afterglow detection
  55. Fermi GRB 200803B: Global MASTER-Net observations report
  56. GRB 200803A: Fermi-LAT detection
  57. GRB 200803A: MASTER optical counterpart discovery
  58. GRB 200803A: Tiled Swift observations
  59. Fermi GRB 200803A: Global MASTER-Net observations report
  60. GRB 200801B: AstroSat CZTI detection
  61. Fermi GRB 200801B: Global MASTER-Net observations report
  62. Fermi GRB 200802A: Global MASTER-Net observations report
  63. AX J1846.4-0258: Swift-BAT refined analysis
  64. Konus-Wind detection of GRB 200729A
  65. Fermi GRB 200801A: Global MASTER-Net observations report
  66. GRB 200729A: RT-22 observations at 36.8 GHz
  67. GRB 200729A: VLA Observations
  68. GRB 200729A: Nanshan/NEXT optical upper limit
  69. GRB 200729A: Swift-BAT refined analysis
  70. GRB 200729A: further analysis of the NOT data
  71. GRB 200729A: Swift/UVOT Upper Limits
  72. GRB 200729A: Swift-XRT refined Analysis
  73. Fermi-GBM Sub-Threshold candidate for GRB 200729A
  74. GRB 200729A: Pan-STARRS pre-explosion source detection
  75. GRB 200729A: Spitzer archival source detection
  76. GRB 200729A: TNG NIR upper limits
  77. GRB 200729A: NOT optical upper limits
  78. Swift GRB 200729A: Global MASTER-Net observations report
  79. IceCube GCN Notice 134327_10548129 retraction
  80. GRB 200723A: ATLAS observations of GOTO candidate AT2020qer
  81. GRB 200723A: Swift ToO observations
  82. GRB 200723A: GOTO candidate afterglow and host galaxy
  83. Fermi GRB 200723A: Global MASTER-Net observations report
  84. GRB 200716C: Kitab optical observations
  85. GRB 200716C: CAHA optical observation // Anomalous light curve behavior?
  86. GRB 200716C: CrAO, Terskol, Assy-Turgen optical observations
  87. GRB 200714E: Swift-XRT afterglow detection
  88. GRB 200716C: FRAM-ORM afterglow detection
  89. Konus-Wind observation of GRB 200716C: correction to GCN 28147
  90. Konus-Wind observation of GRB 200716C
  91. GRB 200716C: VIRT optical detection.
  92. GRB 200716C: Insight-HXMT/HE detection
  93. AMON IC_HAWC 170720: Correction to ANTARES GCN 28142
  94. Fermi GRB 200718A: Global MASTER-Net observations report
  95. AMON IC_HAWC 170720: No Neutrino Counterpart detected with ANTARES
  96. GRB 200716C: CALET Gamma-Ray Burst Monitor detection
  97. GRB 200716C: Optical observations from HCT
  98. GRB 200716B: Insight-HXMT/HE detection
  99. GRB 200716C: Swift-BAT refined analysis
  100. GRB 200716C: Fermi GBM detection

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