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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"

26042 results found.

  1. Fermi GBM Sub-Threshold Detection of GRB 220325A
  2. GRB 220325A: Enhanced Swift-XRT position
  3. GRB 220325A: MASTER Global Robotic Net optical observations
  4. GRB 220325A: Swift detection of a burst
  5. GRB 220319A: GRANDMA observations
  6. GRB 220319A: Swift-BAT refined analysis
  7. GRB 220317A: Fermi GBM detection
  8. GRB 220319A: MITSuME Akeno optical upper limits
  9. GRB220319A: Optical observations from NOT
  10. GRB 220319A: LCO Optical Upper Limit
  11. GRB 220319A: Mondy optical uper limit
  12. GRB 220319A: Swift-XRT refined Analysis
  13. GRB 220319A: Enhanced Swift-XRT position
  14. GRB 220319A: MASTER Global Robotic Net optical observations
  15. GRB 220319A: Swift detection of a burst
  16. GRB 220317A: Swift/BAT-GUANO detection outside the coded FOV
  17. GRB 220306B: Swift/UVOT Upper Limits
  18. GRB 220310C: Fermi GBM observation
  19. GRB 210722A: TAROT Reunion observatory optical light curve
  20. GRB 210222B: TAROT Reunion observatory optical light curve
  21. GRB 201021C: TAROT Reunion observatory optical light curve
  22. GRB 220310A: K-800 of Terskol observatory optical upper limit
  23. GRB 220310C: Swift-XRT observations
  24. GRB 220310C: Swift ToO observations
  25. GRB 220310C: Swift/BAT-GUANO candidate arcminute localization
  26. ZTF22aabjpxh/AT2022cva (GRB 220219B): evidence of supernova in LBT spectra
  27. GRB 220310A: GIT confirmation of optical afterglow.
  28. GRB 220306B: Nanshan/NEXT optical upper limit
  29. ZTF22aabjpxh/AT2022cva (GRB 220219B): continued optical observations, possible photometric evidence of SN
  30. Fermi GBM Detection of GRB 220308A
  31. GRB 220308A: AGILE detection
  32. GRB 220310A: Swift ToO observations
  33. Konus-Wind detection of GRB 220308A
  34. GRB 220308A: Swift/BAT-GUANO detection outside the coded FOV
  35. IPN triangulation of GRB 220308A (long / very bright)
  36. GRB 220306B: Mondy optical observations, confirmation afterglow candidate
  37. GRB 220306B: Tautenburg observations
  38. GRB 220304A Fermi GBM detection
  39. GRB 220306B: Swift-BAT refined analysis
  40. GRB 220306B: AbAO optical observations, possible afterglow candidate
  41. GRB 220306B: BOOTES-1 optical upper limit
  42. GRB 220306B: Swift-XRT refined Analysis
  43. GRB 220306B: Fermi GBM observation
  44. GRB 220306B: Enhanced Swift-XRT position
  45. Swift GRB 220306B: Global MASTER-Net observations report
  46. GRB 220305A: Swift-BAT refined analysis
  47. GRB 220306B: Swift detection of a burst
  48. Fermi GBM Sub-Threshold Detection of GRB 220305A
  49. GRB 220305A: Swift-XRT refined Analysis
  50. GRB 220305A: Enhanced Swift-XRT position
  51. IceCube-220303A: One X-ray counterpart from Swift/XRT follow up observations
  52. Swift GRB 220305A: Global MASTER-Net observations report
  53. GRB 220305A: Swift-XRT observations
  54. GRB 220305A: Swift detection of a burst
  55. ZTF22aabjpxh/AT2022cva (GRB 220219B): continued optical observations, SN signature search
  56. GRB 220302A: Swift/UVOT Upper Limits
  57. GRB 220304A: Swift/BAT-GUANO detection outside the coded FOV
  58. GRB 220302A: Swift-XRT refined Analysis
  59. GRB 220302A: BOOTES-5/JGT optical upper limit
  60. Swift resumes autonomous slewing
  61. GRB 220302A: Enhanced Swift-XRT position
  62. GRB 220302A: Swift afterglow detection
  63. GRB 220222A: CALET Gamma-Ray Burst Monitor detection
  64. Swift GRB 220302A: Global MASTER-Net observations report
  65. GRB 220302A: Swift detection of a burst
  66. GRB 220228A: Fermi-LAT detection
  67. Konus-Wind detection of GRB 220222A
  68. IPN triangulation of GRB 220222A
  69. GRB 220101A: The first example of a Petanova
  70. GCN Circ.draft on GRB 220222A
  71. GRB 220219B: Swift-XRT observations
  72. ZTF22aabjpxh/AT2022cva (GRB 220219B): Mondy optical observations
  73. ZTF22aaajecp/AT2022cmc: Swift Observation and a UV Detection
  74. ZTF22aabjpxh/AT2022cva: NICER X-ray detection is consistent with a GRB afterglow
  75. GRB 220219B: Swift ToO observations
  76. GRB 220222A: Swift/BAT-GUANO detection outside the coded FOV
  77. ZTF22aabjpxh/AT2022cva: Assy optical observations
  78. ZTF22aaajecb/AT2022cmc: Submillimeter Array detection
  79. ZTF22aaajecb/AT 2022cmc: CAHA 2.2m/CAFOS detection, luminous transient
  80. IPN triangulation of GRB 220219B (consistent with ZTF22aabjpxh/AT2022cva)
  81. ZTF22aabjpxh/AT2022cva: ZTF Discovery of a Rapidly Fading Transient with a Likely Long-GRB Counterpart
  82. GRB 220218A: BOOTES-5/JGT optical upper limit
  83. GRB 220218A: Swift detection of a burst
  84. Swift GRB220218.94: Global MASTER-Net observations report
  85. Swift resumes pointed science observations
  86. Konus-Wind detection of GRB 220211A
  87. ZTF22aaajecp/AT2022cmc: Liverpool Telescope photometry
  88. GRB 220211A: Fermi GBM observation
  89. ZTF22aaajecp/AT2022cmc: Zwicky Transient Facility discovery of a fast and red optical transient
  90. GRB 220210A: Mondy, AbAO and Terskol optical upper limits
  91. IPN triangulation of GRB 220211A (short)
  92. GRB 220210A: Insight-HXMT/HE detection
  93. GRB 220211A: Swift/BAT-GUANO detection outside the coded FOV (short)
  94. GRB 220210A: 1.5m OSN optical upper limit
  95. GRB 220210A: Fermi GBM detection
  96. GRB 220210A: Fermi-LAT detection
  97. GRB 220210A: AGILE detection
  98. GRB 220210A: BOOTES-5/JGT optical afterglow candidate discarded
  99. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  100. GRB 220210A: Swift/BAT-GUANO localization

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