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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"

27773 results found.

  1. GRB 230802A: Fermi GBM observation
  2. GRB 230802A: Swift-BAT refined analysis
  3. GRB 230804A: Fermi GBM Final Real-time Localization
  4. IPN triangulation of GRB 230803A
  5. GRB 230802A: Swift/UVOT Upper Limits
  6. GRB 230803A: AstroSat CZTI detection
  7. LIGO/Virgo/KAGRA S230802aq: AstroSat CZTI non-detection and upper limits
  8. GRB 230803A: Fermi GBM Final Real-time Localization
  9. GRB 230802B: Fermi GBM Final Localization
  10. Swift GRB 230802A: Global MASTER-Net observations report
  11. GRB 230802A: BOOTES-5/JGT optical upper limit
  12. LIGO/Virgo/KAGRA S230802aq: Upper limits from Fermi-GBM Observations
  13. GRB 230802A: Swift-XRT refined Analysis
  14. GRB 230802A: Enhanced Swift-XRT position
  15. GRB 230802A: Swift detection of a burst
  16. LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
  17. LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
  18. GRB 230731A: Fermi GBM Final Real-time Localization
  19. GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
  20. GRB 230728A: Swift-BAT refined analysis
  21. GRB 230723B: Swift-BAT refined analysis
  22. GRB 230723B: MITSuME Ishigaki optical observation
  23. GRB 230728A: BOOTES-1 optical upper limit
  24. GRB 230728A: Fermi GBM Observation
  25. GRB 230728A: LCOGT Optical Upper Limit
  26. GRB 230728A: Swift/UVOT Upper Limits
  27. GRB 230728A: Swift-XRT refined Analysis
  28. GRB 230728A: Enhanced Swift-XRT position
  29. GRB 230728A: NOT optical observations and possible host galaxy
  30. GRB 230727A: AstroSat CZTI detection
  31. GRB 230728A: Swift detection of a burst
  32. Swift GRB230728.12: Global MASTER-Net observations report
  33. GRB 230727A: Swift/BAT-GUANO detection of a burst
  34. IceCube-230727A - IceCube observation of a high-energy neutrino candidate track-like event
  35. GRB 230727A: Fermi GBM Final Real-time Localization
  36. GRB 230723B: Further CAHA observations and host galaxy detection
  37. Konus-Wind detection of GRB 230723A
  38. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  39. IceCube-230724A - IceCube observation of a high-energy neutrino candidate track-like event
  40. IBAS trigger number 10337: not a real GRB
  41. IceCube-230725A - IceCube observation of a high-energy neutrino candidate track-like event
  42. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  43. IPN triangulation of GRB 230723A (short)
  44. GRB 230725B: Fermi GBM Final Real-time Localization
  45. GRB 230725A: Fermi GBM Final Real-time Localization
  46. GRB 230723B: Leavitt Observatory upper limit
  47. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  48. GRB 230723B: Montarrenti Observatory upper limit
  49. GRB 230723B: Bassano Bresciano Observatory upper limit
  50. GRB 230723B: Fermi GBM observation
  51. GRB 230723B: Swift-XRT refined Analysis
  52. GRB 230724A: Fermi GBM Final Real-time Localization
  53. GRB 230723B: Swift/UVOT Upper Limits
  54. Swift GRB 230723B: Global MASTER-Net observations report
  55. Swift-XRT position for GRB 230723B
  56. GRB 230723A: AGILE/MCAL detection
  57. GRB 230723B: Swift-XRT observations
  58. GRB 230723B: Swift detection of a burst
  59. GRB 230723A: Fermi GBM Final Real-time Localization
  60. Swift GRB230720.30: Global MASTER-Net observations report
  61. IPN triangulation of GRB 230715D
  62. Swift Trigger 1180063 is not a GRB
  63. Swift Trigger 1180060 is not a GRB
  64. Swift Trigger 1180055 is not a GRB
  65. GRB 230718A: Final Localization Correction
  66. GRB 230718A: Fermi GBM Final Real-time Localization
  67. IPN triangulation of GRB 230712C (short)
  68. IPN triangulation of GRB 230712A (short)
  69. GRB 230717A: Fermi GBM Final Real-time Localization
  70. LIGO/Virgo/KAGRA S230715bw: Retraction of GW compact binary merger candidate
  71. GRB 230715A: Fermi GBM Final Real-time Localization
  72. IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
  73. GRB 230713A: Fermi GBM Final Real-time Localization
  74. GRB 230709B: CALET Gamma-Ray Burst Monitor detection
  75. GRB 230703A: CALET Gamma-Ray Burst Monitor detection
  76. GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  77. IceCube-230708A: Upper limits from Swift/BAT-GUANO
  78. GRB 230712B: Fermi GBM Final Localization
  79. GRB 230707A: Swift/BAT-GUANO position correction
  80. GRB 230712A: Fermi GBM Final Real-time Localization
  81. GRB 230709C: GRBAlpha detection
  82. GRB 230709B: GRBAlpha detection
  83. GRB 230709C: Fermi GBM Detection
  84. GRB 230709C: Fermi GBM Final Localization
  85. GRB 230707B: Fermi GBM Observation
  86. GRB 230710A: Fermi GBM Final Real-time Localization
  87. IceCube-230707A: No candidates detected by Swift-XRT
  88. Swift Trigger 1178410 is not an astrophysical event
  89. GRB 230709C: AstroSat CZTI detection
  90. GRB 230707B: CALET Gamma-Ray Burst Monitor detection
  91. Swift Trigger 1178410: possible GRB 230709A
  92. GRB 230628C: GRID Detection
  93. IceCube-230708A - IceCube observation of a high-energy neutrino candidate track-like event
  94. GRB 230707B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  95. GRB 230707A: Swift-XRT observations
  96. IceCube-230707B - IceCube observation of a high-energy neutrino candidate track-like event
  97. GRB 230707B: Fermi GBM Final Real-time Localization
  98. IceCube-230707A - IceCube observation of a high-energy neutrino candidate track-like event
  99. GRB 230707A: Fermi GBM Detection
  100. GRB 230707A: Swift ToO observations

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