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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"

27777 results found.

  1. GRB 231111A: Enhanced Swift-XRT position
  2. GRB 231111A: GECAM-C detection of a long burst
  3. GRB 231110A: GECAM detection
  4. GRB 231110A: SAO RAS optical observations
  5. GRB 231110A: Swift-XRT afterglow detection
  6. GRB231111A: YAHPT Observations
  7. GRB231111A: GIT confirmation of the optical afterglow
  8. GRB 231111A: MASTER OT earlier detection
  9. GRB 231111A: Nanshan/HMT optical observations
  10. GRB 231111A: Swift detection of a burst with an optical counterpart
  11. Swift GRB231111.60: Global MASTER-Net observations report
  12. GRB231110A: WFST Observation and upper limits
  13. Swift GRB231110.89: Global MASTER-Net observations report
  14. GRB 231110A: Swift detection of a burst
  15. GRB 231109A: Fermi GBM Final Localization
  16. GRB 231108A: Fermi GBM Final Real-time Localization
  17. GRB 231106A: AstroSat CZTI detection
  18. GRB 231106A: CALET Gamma-Ray Burst Monitor detection
  19. GRB 231104A: Swift-BAT refined analysis
  20. GRB 231104A: FRAM-ORM optical limit
  21. LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
  22. GRB 231104A: NuSTAR Observation of the prompt emission
  23. GRB 231106A: Fermi GBM Final Real-time Localization
  24. GRB 231104A: 3.6m DOT optical upper limit
  25. GRB 231104A: NOT upper limit
  26. GRB 231104A: Fermi GBM Observation
  27. GRB 231104B: Fermi GBM Final Real-time Localization
  28. GRB 231104A: AKO Upper Limit
  29. GRB 231104A: AstroSat CZTI detection
  30. GRB 231104A: Swift-XRT refined Analysis
  31. GRB 231104A: Fermi-LAT detection
  32. GRB 231104A: Swift/UVOT Upper Limits
  33. GRB 231104A: Enhanced Swift-XRT position
  34. GRB231104A: LCOGT Optical Upper Limits
  35. GRB 231104A: Swift detection of a bright burst
  36. GRB 231104A: Fermi GBM Final Real-time Localization
  37. Swift GRB231104.07: Global MASTER-Net observations report
  38. GRB 231103A: Fermi GBM Final Real-time Localization
  39. IceCube-231103A - IceCube observation of a high-energy neutrino candidate track-like event
  40. GRB 231101A: Glowbug gamma-ray detection
  41. GRB 231024A: GRANDMA observations of AT2023vuc/GOTO23baj candidate
  42. New Swift-BAT/GUANO and IceCube Notices Available via GCN Kafka
  43. GRB 231101A: Fermi GBM Final Real-time Localization
  44. GRB 231030B: GRBAlpha detection
  45. GRB 231028B: VZLUSAT-2 detection
  46. GRB 231030B: Fermi GBM Detection
  47. GRB 231030B: AstroSat CZTI detection
  48. IPN triangulation of GRB 231020A
  49. GRB 231030B: Fermi GBM Final Real-time Localization
  50. GRB 231028A: Swift-BAT refined analysis
  51. LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
  52. LIGO/Virgo/KAGRA S231030av: Retraction of GW compact binary merger candidate
  53. GRB 231028A: CALET Gamma-Ray Burst Monitor detection
  54. GRB 231030A: Fermi GBM Final Real-time Localization
  55. GRID detection of GRB 231020A
  56. GRB 231028A: AstroSat CZTI detection
  57. GRB 231028A: Glowbug gamma-ray detection
  58. GRB 231028A: Fermi GBM Detection
  59. Swift GRB 231028A: Global MASTER-Net observations report
  60. GRB 231028A: Swift detection of a burst
  61. GRB 231028A: Fermi GBM Final Real-time Localization
  62. IceCube-231027A - IceCube observation of a high-energy neutrino candidate track-like event
  63. GRB 231019A: Glowbug gamma-ray detection
  64. GRB 231025A: Fermi GBM Observation
  65. GRB 231025A: Swift/BAT-GUANO detection of a likely short burst
  66. GRB 231025A: Fermi GBM Final Localization
  67. GRB 231024A: X-shooter spectroscopy of AT2023vuc/GOTO23baj reveals a young supernova with flash ionisation features
  68. GRB 231020A: AstroSat CZTI detection
  69. GRB 231020B: AstroSat CZTI detection
  70. GRB 231024A: Fermi GBM Final Localization
  71. GRB 231018A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  72. LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO
  73. GRB 231020A: Fermi GBM Detection
  74. GRID detection of GRB 231004A
  75. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  76. GRB 231019A: VZLUSAT-2 detection
  77. GRB 231018A: VZLUSAT-2 detection
  78. GRB 231020B: Fermi GBM Final Real-time Localization
  79. LIGO/Virgo/KAGRA S231020ba: Upper limits from Fermi-GBM Observations
  80. GRB 231015A: NuSTAR Detection of Prompt Emission
  81. GRB 231020A: Fermi GBM Final Real-time Localization
  82. GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  83. GRB 231017A: 1.3m DFOT Optical upper limit
  84. GRB 231018A: GRBAlpha detection
  85. GRB 231018A: CALET Gamma-Ray Burst Monitor detection
  86. GRB 231018A: Glowbug gamma-ray detection
  87. Konus-Wind detection of GRB 231018A
  88. IPN triangulation of GRB 231018A
  89. GRB 231017A: Swift/UVOT Upper Limit
  90. GRB 230911C: ATCA detection of possible radio counterpart
  91. GRB 231019A: Fermi GBM Final Real-time Localization
  92. GRB 231017A: GOTO optical upper limits
  93. GRB 231017A: JinShan optical upper limit
  94. GRB 231017A: Las Cumbres optical upper limit
  95. GRB 231015A: Glowbug gamma-ray detection
  96. GRB 231017A: LCOGT Optical Upper Limits
  97. GRB231017A: GROWTH-India upper limits on the optical afterglow
  98. GRB 231015A: AstroSat CZTI detection
  99. GRB 231018A: Fermi GBM Detection
  100. GRB 231017A: Fermi GBM Detection

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