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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"

33589 results found.

  1. ZTF22aaajecp/AT2022cmc: continued optical observations (Mondy, TSHAO, AbAO)
  2. GRB 220325A: Tautenburg observations
  3. GRB 220326A: Fermi GBM Final Localization
  4. GRB 220325A: LCO Optical Upper Limits
  5. GRB 220325A: Swift-XRT refined Analysis
  6. GRB 220325A: 1.3m DFOT Optical upper limit
  7. GRB 220325B: Fermi GBM Final Localization
  8. Fermi GBM Sub-Threshold Detection of GRB 220325A
  9. GRB 220325A: Enhanced Swift-XRT position
  10. GRB 220325A: MASTER Global Robotic Net optical observations
  11. GRB 220324A: AstroSat CZTI detection
  12. GRB 220325A: Swift detection of a burst
  13. GRB 220323A: AstroSat CZTI detection
  14. GRB 220319A: GRANDMA observations
  15. GRB 220323A: AGILE/MCAL detection
  16. IPN triangulation of GRB 220320A
  17. GRB 220323A: Fermi GBM Final Real-time Localization
  18. GRB 220319A: Swift-BAT refined analysis
  19. GRB 220316A: AstroSat CZTI detection
  20. GRB 220320A: AstroSat CZTI detection
  21. GRB 220317A: Fermi GBM detection
  22. GRB 220321A: Fermi GBM Final Localization
  23. GRB 220319A: MITSuME Akeno optical upper limits
  24. GRB 220319A: LCO Optical Upper Limit
  25. GRB 220319A: Mondy optical uper limit
  26. GRB 220319A: Swift-XRT refined Analysis
  27. GRB 220319A: Enhanced Swift-XRT position
  28. GRB 220319A: MASTER Global Robotic Net optical observations
  29. GRB 220319A: Swift detection of a burst
  30. GRB 220317A: Swift/BAT-GUANO detection outside the coded FOV
  31. GRB 220310A: MITSuME Akeno optical observation
  32. GRB 220317A: Fermi GBM Final Real-time Localization
  33. GRB 220315A: MASTER Global Robotic Net optical observations
  34. GRB 220311A: Fermi GBM observation
  35. GRB 220306B: Swift/UVOT Upper Limits
  36. GRB 220315A: Fermi GBM Final Real-time Localization
  37. GRB 220311A: MITSuME Akeno optical upper limits
  38. IPN triangulation of GRB 220310A
  39. GRB 220310C: Fermi GBM observation
  40. GRB 210722A: TAROT Reunion observatory optical light curve
  41. GRB 210222B: TAROT Reunion observatory optical light curve
  42. GRB 201021C: TAROT Reunion observatory optical light curve
  43. GRB 220310A: K-800 of Terskol observatory optical upper limit
  44. GRB 220310A: [KAO-Egypt] SDSS r, i observation
  45. GRB 220310C: Swift-XRT observations
  46. Konus-Wind detection of GRB 220310A
  47. GRB 220310C: Swift ToO observations
  48. GRB 220310C: Swift/BAT-GUANO candidate arcminute localization
  49. GRB 220311A: MASTER OT retraction
  50. GRB 220311A: A long GRB detected by INTEGRAL
  51. GRB 220311A: Fermi GBM Final Real-time Localization
  52. ZTF22aabjpxh/AT2022cva (GRB 220219B): evidence of supernova in LBT spectra
  53. GRB 220310A: GIT confirmation of optical afterglow.
  54. GRB 220306B: Nanshan/NEXT optical upper limit
  55. ZTF22aabjpxh/AT2022cva (GRB 220219B): continued optical observations, possible photometric evidence of SN
  56. GRB 220310C: Fermi GBM Final Real-time Localization
  57. Fermi GBM Detection of GRB 220308A
  58. GRB 220308A: AGILE detection
  59. GRB 220310A: MASTER optical counterpart detection
  60. GRB 220310A: Swift ToO observations
  61. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  62. Fermi GRB 220310B: Global MASTER-Net observations report
  63. GRB 220310B: Fermi GBM Final Real-time Localization
  64. GRB 220308B: Fermi GBM detection
  65. GRB 220310A: MAXI/GSC detection
  66. Konus-Wind detection of GRB 220308A
  67. CALET Gamma-Ray Burst Monitor detection of GRB 220308A and its possible precursor
  68. Fermi GRB 220309A: Global MASTER-Net observations report
  69. GRB 220309A: Fermi GBM Final Real-time Localization
  70. GRB 220308A: Swift/BAT-GUANO detection outside the coded FOV
  71. IPN triangulation of GRB 220308A (long / very bright)
  72. GRB 220306B: Mondy optical observations, confirmation afterglow candidate
  73. IPN triangulation of GRB 220305B
  74. GRB 220306B: Tautenburg observations
  75. GRB 220304A Fermi GBM detection
  76. GRB 220306B: Swift-BAT refined analysis
  77. GRB 220306B: AbAO optical observations, possible afterglow candidate
  78. GRB 220306B: BOOTES-1 optical upper limit
  79. GRB 220306B: Swift-XRT refined Analysis
  80. GRB 220306B: Fermi GBM observation
  81. GRB 220306B: Enhanced Swift-XRT position
  82. Swift GRB 220306B: Global MASTER-Net observations report
  83. GRB 220305A: Swift-BAT refined analysis
  84. GRB 220306B: Swift detection of a burst
  85. Fermi GBM Sub-Threshold Detection of GRB 220305A
  86. GRB 220305A: Swift-XRT refined Analysis
  87. Fermi GRB 220306A: Global MASTER-Net observations report
  88. GRB 220306A: Fermi GBM Final Real-time Localization
  89. Fermi GRB 220305A: Global MASTER-Net observations report
  90. Correction to GCN 31689: Fermi GBM Report of GRB 220305A should be GRB 220305B
  91. GRB 220305A: Fermi GBM observation
  92. GRB 220305A: Enhanced Swift-XRT position
  93. Swift GRB 220305A: Global MASTER-Net observations report
  94. GRB 220305A: Swift-XRT observations
  95. GRB 220305A: Swift detection of a burst
  96. ZTF22aabjpxh/AT2022cva (GRB 220219B): continued optical observations, SN signature search
  97. GRB 220302A: Swift/UVOT Upper Limits
  98. GRB 220304A: Swift/BAT-GUANO detection outside the coded FOV
  99. Fermi GRB 220304A: Global MASTER-Net observations report
  100. GRB 220304A: BALROG localization (Fermi Trigger / GRB 220304228)

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