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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. Fermi Gamma-ray Burst Monitor trigger 220331776/670444627 is not a GRB
  2. GRB 220331A: Fermi GBM Final Real-time Localization
  3. Fermi GRB 220330A: Global MASTER-Net observations report
  4. GRB 220330A: Fermi GBM Final Real-time Localization
  5. ZTF22aaajecp/AT2022cmc: 1.3m DFOT Optical observations
  6. GRB 220325A: GRANDMA observations
  7. GRB 220320A: Detection by VZLUSAT-2
  8. Konus-Wind observation of GRB 220320A
  9. GRB 220325A: Swift/UVOT Upper Limits
  10. GRB 211024B: Host galaxy redshift from X-shooter/VLT
  11. GRB 220325A: Swift-BAT refined analysis
  12. ZTF22aaajecp/AT2022cmc: continued optical observations (Mondy, TSHAO, AbAO)
  13. GRB 220325A: Tautenburg observations
  14. GRB 220326A: Fermi GBM Final Localization
  15. GRB 220325A: LCO Optical Upper Limits
  16. GRB 220325A: Swift-XRT refined Analysis
  17. GRB 220325A: 1.3m DFOT Optical upper limit
  18. GRB 220325B: Fermi GBM Final Localization
  19. Fermi GBM Sub-Threshold Detection of GRB 220325A
  20. GRB 220325A: Enhanced Swift-XRT position
  21. GRB 220325A: MASTER Global Robotic Net optical observations
  22. GRB 220324A: AstroSat CZTI detection
  23. GRB 220325A: Swift detection of a burst
  24. GRB 220323A: AstroSat CZTI detection
  25. GRB 220319A: GRANDMA observations
  26. GRB 220323A: AGILE/MCAL detection
  27. IPN triangulation of GRB 220320A
  28. GRB 220323A: Fermi GBM Final Real-time Localization
  29. GRB 220319A: Swift-BAT refined analysis
  30. GRB 220316A: AstroSat CZTI detection
  31. GRB 220320A: AstroSat CZTI detection
  32. GRB 220317A: Fermi GBM detection
  33. GRB 220321A: Fermi GBM Final Localization
  34. GRB 220319A: MITSuME Akeno optical upper limits
  35. GRB220319A: Optical observations from NOT
  36. GRB 220319A: LCO Optical Upper Limit
  37. GRB 220319A: Mondy optical uper limit
  38. GRB 220319A: Swift-XRT refined Analysis
  39. GRB 220319A: Enhanced Swift-XRT position
  40. GRB 220319A: MASTER Global Robotic Net optical observations
  41. GRB 220319A: Swift detection of a burst
  42. Fermi-LAT Gamma-ray Observations of IceCube-220317A
  43. IceCube-220317A: Upper limits from a search for additional neutrino events in IceCube
  44. GRB 220317A: Swift/BAT-GUANO detection outside the coded FOV
  45. GRB 220310A: MITSuME Akeno optical observation
  46. IceCube-220317A: MASTER Global Robotic Net optical observations
  47. GRB 220317A: Fermi GBM Final Real-time Localization
  48. IceCube-220317A - IceCube observation of a high-energy neutrino candidate track-like event
  49. GRB 220315A: MASTER Global Robotic Net optical observations
  50. GRB 220311A: Fermi GBM observation
  51. GRB 220306B: Swift/UVOT Upper Limits
  52. GRB 220315A: Fermi GBM Final Real-time Localization
  53. GRB 220311A: MITSuME Akeno optical upper limits
  54. IPN triangulation of GRB 220310A
  55. GRB 220310C: Fermi GBM observation
  56. GRB 210722A: TAROT Reunion observatory optical light curve
  57. GRB 210222B: TAROT Reunion observatory optical light curve
  58. GRB 201021C: TAROT Reunion observatory optical light curve
  59. GRB 220310A: K-800 of Terskol observatory optical upper limit
  60. GRB 220310A: [KAO-Egypt] SDSS r, i observation
  61. GRB 220310C: Swift-XRT observations
  62. Konus-Wind detection of GRB 220310A
  63. GRB 220310C: Swift ToO observations
  64. GRB 220310C: Swift/BAT-GUANO candidate arcminute localization
  65. GRB 220311A: MASTER OT retraction
  66. GRB 220311A: A long GRB detected by INTEGRAL
  67. Integral GRB220311.69: Global MASTER-Net observations report
  68. Integral GRB220311.69: Global MASTER-Net observations report
  69. Integral GRB220311.69: Global MASTER-Net OT detection
  70. GRB 220311A: Fermi GBM Final Real-time Localization
  71. ZTF22aabjpxh/AT2022cva (GRB 220219B): evidence of supernova in LBT spectra
  72. GRB 220310A: GIT confirmation of optical afterglow.
  73. GRB 220306B: Nanshan/NEXT optical upper limit
  74. ZTF22aabjpxh/AT2022cva (GRB 220219B): continued optical observations, possible photometric evidence of SN
  75. GRB 220310C: Fermi GBM Final Real-time Localization
  76. Fermi GBM Detection of GRB 220308A
  77. GRB 220308A: AGILE detection
  78. GRB 220310A: MASTER optical counterpart detection
  79. GRB 220310A: Swift ToO observations
  80. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  81. ZTF22aaajecp/AT2022cmc: Hubble Space Telescope Observations
  82. Fermi GRB 220310B: Global MASTER-Net observations report
  83. GRB 220310B: Fermi GBM Final Real-time Localization
  84. GRB 220308B: Fermi GBM detection
  85. GRB 220310A: MAXI/GSC detection
  86. MAXI GRB220310.02: Global MASTER-Net observations report
  87. Konus-Wind detection of GRB 220308A
  88. IceCube-220306A: No significant detection in HAWC
  89. IceCube-220303A: No significant detection in HAWC
  90. ZTF22aabjpxh/AT2022cva: AMI-LA radio observation
  91. CALET Gamma-Ray Burst Monitor detection of GRB 220308A and its possible precursor
  92. Fermi GRB 220309A: Global MASTER-Net observations report
  93. GRB 220309A: Fermi GBM Final Real-time Localization
  94. GRB 220308A: Swift/BAT-GUANO detection outside the coded FOV
  95. IPN triangulation of GRB 220308A (long / very bright)
  96. GRB 220306B: Mondy optical observations, confirmation afterglow candidate
  97. IPN triangulation of GRB 220305B
  98. Fermi trigger No 668410535: Global MASTER-Net observations report
  99. GRB 220306B: Tautenburg observations
  100. GRB 220304A Fermi GBM detection

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