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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"

36144 results found.

  1. GRB231111A: YAHPT Observations
  2. GRB231111A: GIT confirmation of the optical afterglow
  3. GRB 231111A: MASTER OT earlier detection
  4. GRB 231111A: Nanshan/HMT optical observations
  5. GRB 231111A: Swift detection of a burst with an optical counterpart
  6. GRB231110A: WFST Observation and upper limits
  7. GRB 231110A: Swift detection of a burst
  8. GRB 231109A: Fermi GBM Final Localization
  9. Fermi GRB 231108A: Global MASTER-Net observations report
  10. GRB 231108A: Fermi GBM Final Real-time Localization
  11. GRB 231106A: AstroSat CZTI detection
  12. GRB 231106A: CALET Gamma-Ray Burst Monitor detection
  13. GRB 231104A: Swift-BAT refined analysis
  14. Fermi Gamma-ray Burst Monitor trigger 231107654 / 721064512 is not a GRB
  15. GRB 231104A: FRAM-ORM optical limit
  16. LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
  17. Fermi GRB 231106A: Global MASTER-Net observations report
  18. GRB 231104A: Wendelstein Optical/Infrared Observations
  19. GRB 231104A: NuSTAR Observation of the prompt emission
  20. GRB 231106A: Fermi GBM Final Real-time Localization
  21. GRB 231104A: 3.6m DOT optical upper limit
  22. IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
  23. GRB 231104A: NOT upper limit
  24. GRB 231104A: Fermi GBM Observation
  25. GRB 231104B: Fermi GBM Final Real-time Localization
  26. Fermi GRB 231103A: Global MASTER-Net observations report
  27. GRB 231104A: AKO Upper Limit
  28. GRB 231104A: AstroSat CZTI detection
  29. GRB 231104A: Swift-XRT refined Analysis
  30. GRB 231104A: Fermi-LAT detection
  31. GRB 231104A: Swift/UVOT Upper Limits
  32. GRB 231104A: Enhanced Swift-XRT position
  33. GRB231104A: LCOGT Optical Upper Limits
  34. GRB 231104A: Swift detection of a bright burst
  35. GRB 231104A: Fermi GBM Final Real-time Localization
  36. GRB 231103A: Fermi GBM Final Real-time Localization
  37. GRB 231101A: Glowbug gamma-ray detection
  38. GRB 231024A: GRANDMA observations of AT2023vuc/GOTO23baj candidate
  39. GRB 231101A: Fermi GBM Final Real-time Localization
  40. GRB 231030B: GRBAlpha detection
  41. GRB 231028B: VZLUSAT-2 detection
  42. GRB 231030B: Fermi GBM Detection
  43. GRB 231030B: AstroSat CZTI detection
  44. Fermi GRB 231030B: Global MASTER-Net observations report
  45. IPN triangulation of GRB 231020A
  46. GRB 231030B: BALROG localization (Fermi Trigger 720388704 / GRB 231030832)
  47. GRB 231030B: Fermi GBM Final Real-time Localization
  48. GRB 231028A: Swift-BAT refined analysis
  49. IceCube-231027A: Upper limits from a search for additional neutrino events in IceCube
  50. LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
  51. GRB 231024A: AKO Optical Counterpart Candidate
  52. GRB 231028A: CALET Gamma-Ray Burst Monitor detection
  53. Fermi GRB 231030A: Global MASTER-Net observations report
  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. GRB 231019A: Glowbug gamma-ray detection
  63. GRB 231025A: Fermi GBM Observation
  64. GRB 231024A: 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 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
  69. GRB 231020A: AstroSat CZTI detection
  70. GRB 231020B: AstroSat CZTI detection
  71. GRB 231024A: GOTO optical counterpart candidate
  72. GRB 231024A: Fermi GBM Final Localization
  73. GRB 231018A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  74. LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO
  75. GRB 231020A: Fermi GBM Detection
  76. GRID detection of GRB 231004A
  77. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  78. GRB 231019A: VZLUSAT-2 detection
  79. GRB 231018A: VZLUSAT-2 detection
  80. GRB 231020B: BALROG localization (Fermi Trigger 719530557 / GRB 231020900)
  81. GRB 231020B: Fermi GBM Final Real-time Localization
  82. GRB 231020A: BALROG localization (Fermi Trigger / GRB 231020790)
  83. LIGO/Virgo/KAGRA S231020ba: Upper limits from Fermi-GBM Observations
  84. GRB 231015A: NuSTAR Detection of Prompt Emission
  85. Fermi GRB 231020A: Global MASTER-Net observations report
  86. GRB 231020A: Fermi GBM Final Real-time Localization
  87. GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  88. GRB 231017A: 1.3m DFOT Optical upper limit
  89. IceCube-231004A: Upper limits from Fermi-GBM Observations
  90. GRB 231018A: GRBAlpha detection
  91. GRB 231018A: CALET Gamma-Ray Burst Monitor detection
  92. Fermi GRB 231019A: Global MASTER-Net observations report
  93. GRB 231018A: Glowbug gamma-ray detection
  94. Konus-Wind detection of GRB 231018A
  95. IPN triangulation of GRB 231018A
  96. GRB 231017A: Swift/UVOT Upper Limit
  97. GRB 230911C: ATCA detection of possible radio counterpart
  98. GRB 231019A: Fermi GBM Final Real-time Localization
  99. GRB 231017A: GOTO optical upper limits
  100. GRB 231017A: JinShan optical upper limit

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