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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"

19603 results found.

  1. GRB 230802A: Fermi GBM observation
  2. GRB 230802A: Swift-BAT refined analysis
  3. GRB 230802A: Swift/UVOT Upper Limits
  4. Swift GRB 230802A: Global MASTER-Net observations report
  5. GRB 230802A: BOOTES-5/JGT optical upper limit
  6. GRB 230802A: Swift-XRT refined Analysis
  7. GRB 230802A: Enhanced Swift-XRT position
  8. GRB 230802A: Swift detection of a burst
  9. LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
  10. GRB 230728A: Swift-BAT refined analysis
  11. GRB 230723B: Swift-BAT refined analysis
  12. GRB 230723B: MITSuME Ishigaki optical observation
  13. GRB 230728A: BOOTES-1 optical upper limit
  14. GRB 230728A: Fermi GBM Observation
  15. GRB 230728A: LCOGT Optical Upper Limit
  16. GRB 230728A: Swift/UVOT Upper Limits
  17. GRB 230728A: Swift-XRT refined Analysis
  18. GRB 230728A: Enhanced Swift-XRT position
  19. GRB 230728A: NOT optical observations and possible host galaxy
  20. GRB 230727A: AstroSat CZTI detection
  21. GRB 230728A: Swift detection of a burst
  22. Swift GRB230728.12: Global MASTER-Net observations report
  23. GRB 230727A: Swift/BAT-GUANO detection of a burst
  24. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  25. IBAS trigger number 10337: not a real GRB
  26. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  27. GRB 230723B: Leavitt Observatory upper limit
  28. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  29. GRB 230723B: Montarrenti Observatory upper limit
  30. GRB 230723B: Bassano Bresciano Observatory upper limit
  31. GRB 230723B: Fermi GBM observation
  32. GRB 230723B: Swift-XRT refined Analysis
  33. GRB 230723B: Swift/UVOT Upper Limits
  34. Swift GRB 230723B: Global MASTER-Net observations report
  35. Swift-XRT position for GRB 230723B
  36. GRB 230723B: Swift-XRT observations
  37. GRB 230723B: Swift detection of a burst
  38. Swift GRB230720.30: Global MASTER-Net observations report
  39. IPN triangulation of GRB 230715D
  40. Swift Trigger 1180063 is not a GRB
  41. Swift Trigger 1180060 is not a GRB
  42. Swift Trigger 1180055 is not a GRB
  43. IPN triangulation of GRB 230712C (short)
  44. IPN triangulation of GRB 230712A (short)
  45. IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
  46. GRB 230709C: Swift/BAT-GUANO detection of a short burst outside the coded FOV
  47. IceCube-230708A: Upper limits from Swift/BAT-GUANO
  48. GRB 230707A: Swift/BAT-GUANO position correction
  49. GRB 230707B: Fermi GBM Observation
  50. IceCube-230707A: No candidates detected by Swift-XRT
  51. Swift Trigger 1178410 is not an astrophysical event
  52. GRB 230707B: CALET Gamma-Ray Burst Monitor detection
  53. Swift Trigger 1178410: possible GRB 230709A
  54. GRB 230707B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  55. GRB 230707A: Swift-XRT observations
  56. GRB 230707A: Fermi GBM Detection
  57. GRB 230707A: Swift ToO observations
  58. GRB 230707A: Swift/BAT-GUANO arcminute localization of a burst
  59. IBAS trigger number 10311: not a real GRB
  60. GRB 230328B: LBT detection of the likely host galaxy
  61. GRB 230628E: Swift/UVOT Detection
  62. GRB 230628E: Swift-BAT refined analysis
  63. LIGO/Virgo/KAGRA S230627c: Upper limits from Swift/BAT-GUANO
  64. IPN triangulation of GRB 230625B (ultra-long)
  65. GRB 230625B: CALET Gamma-Ray Burst Monitor detection
  66. GRB 230625B: AstroSat CZTI detection
  67. GRB230628E: VLT optical identification of afterglow candidate
  68. GRB 230628E: Swift-XRT refined Analysis
  69. GRB 230628E: Enhanced Swift-XRT position (Correction to name in GCN 34115)
  70. GRB 230628A: Enhanced Swift-XRT position
  71. GRB 230628E: LCOGT Optical Upper Limit
  72. Swift GRB230628.93: Global MASTER-Net observations report
  73. GRB 230628E: Swift detection of a burst
  74. GRB 230628B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  75. GRB 230623B: CALET Gamma-Ray Burst Monitor detection
  76. Konus-Wind detection of GRB 230616A
  77. GRB 230618A: Swift-BAT refined analysis
  78. GRB 230625B: Swift/BAT-GUANO detection of a long burst
  79. GRB 230622A: Swift-BAT refined analysis
  80. GRB 230623A: Swift-XRT observations
  81. GRB 230623B: Swift/BAT-GUANO detection of a long burst outside the coded FOV 
  82. GRB 230623A: Tiled Swift observations
  83. GRB 230623A: Tiled Swift observations
  84. GRB 230622A: Swift-XRT refined Analysis
  85. Swift GRB 230622A: Global MASTER-Net observations report
  86. GRB 230622A: Swift detection of a burst
  87. Fermi GBM-230619: A soft subthreshold candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
  88. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  89. IPN triangulation of GRB 230616A (short)
  90. AT2023lcr: Neil Gehrels Swift Observatory X-ray detection
  91. GRB 230618A: Osservatorio Astronomico Nastro verde upper limit
  92. GRB 230618A: Enhanced Swift-XRT position
  93. GRB 230618A: Swift/UVOT Upper Limits
  94. GRB 230618A: Swift-XRT refined Analysis
  95. GRB 230616A: Swift-XRT observations
  96. GRB 230618A: KAIT Optical Observations
  97. Swift GRB 230618A: Global MASTER-Net observations report
  98. GRB230618A: LCOGT Optical Observations
  99. GRB 230618A: Prompt enhanced Swift-XRT position
  100. GRB 230618A: Swift detection of a burst

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