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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"

37550 results found.

  1. GRB 240805A: Fermi GBM Final Real-time Localization
  2. Fermi GRB 240804A: Global MASTER-Net observations report
  3. EP240802a: Montarrenti Observatory optical upper limit
  4. GRB 240804A: Fermi GBM Final Real-time Localization
  5. Fermi trigger No 744459130: Global MASTER-Net observations report
  6. IPN triangulation of GRB 240802A / EP 240802a
  7. Fermi Gamma-ray Burst Monitor trigger 744459130/240804425 is not a GRB
  8. EP240802A: Bassano Bresciano Observatory upper limit
  9. GRB 240802A: SVOM/GRM observation
  10. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  11. Fermi trigger No 744278264: Global MASTER-Net observations report
  12. GRB 240802A: AstroSat CZTI detection of a long burst
  13. EP240801a: further SAO RAS optical observations
  14. EP240801a: optical observations at CrAO and AbAO
  15. EP240801a: Leavitt Observatory optical observations
  16. EP240801a: SAO RAS optical observations
  17. GRB 240801B: AstroSat CZTI Updated classification - likely a solar flare
  18. GRB 240727C: SVOM/GRM observation
  19. Fermi GBM trigger 744179961 / 240801194 can not be confirmed as a GRB
  20. GRB 240730A: Swift-BAT refined analysis
  21. Fermi trigger No 744204856: Global MASTER-Net observations report
  22. EP240801a: KAIT optical counterpart observations
  23. GRB 240801B: AstroSat CZTI detection of a bright long burst
  24. Fermi GRB 240801A: Global MASTER-Net observations report
  25. GRB 240801A: Fermi GBM Final Real-time Localization
  26. GRB 240730C: AstroSat CZTI detection of a long burst
  27. GRB 240731A: Fermi GBM Final Localization
  28. Fermi trigger No 744128417: Global MASTER-Net observations report
  29. Fermi trigger No 744083370: Global MASTER-Net observations report
  30. GRB 240731A: AstroSat CZTI detection
  31. GRB 240730A: Osservatorio Astronomico Nastro Verde upper limit
  32. GRB240730A: BOOTES-5/JGT early optical upper limit
  33. Fermi Gamma-ray Burst Monitor trigger 744061103/240730818 is not a GRB
  34. Fermi GRB 240730B: Global MASTER-Net observations report
  35. GRB 240730B: Fermi GBM Final Real-time Localization
  36. Swift GRB 240730A: Global MASTER-Net observations report
  37. GRB 240730A: Swift-XRT refined Analysis
  38. GRB 240715A: Swift-XRT afterglow detection
  39. GRB 240730A: KAIT Optical Upper Limit
  40. GRB 240727C: GRBAlpha detection
  41. GRB 240730A: Swift/UVOT Upper Limits
  42. GRB 240730A: Enhanced Swift-XRT position
  43. GRB 240730A: Swift detection of a burst
  44. Fermi trigger No 743953682: Global MASTER-Net observations report
  45. GRB 240727A: Swift-BAT refined analysis
  46. Fermi Gamma-ray Burst Monitor trigger 743953682/240729575 is not a GRB
  47. GRB 240727A: observations of optical counterpart.
  48. GRB 240727B: Swift-XRT observations
  49. Fermi GRB 240727A: Global MASTER-Net observations report
  50. GRB 240727A: Swift/UVOT detection
  51. Fermi trigger No 743868421: Global MASTER-Net observations report
  52. Fermi Gamma-ray Burst Monitor trigger 743868421/240728588 is not a GRB
  53. GRB 240727A: Correction to time in GCN36960
  54. GRB 240727A: Osservatorio Astronomico Nastro Verde upper limit
  55. GRB 240727A: NOT optical observation
  56. GRB 240727A: JinShan optical upper limits
  57. GRB 240727A Bassano Bresciano Observatory upper limit
  58. GRB 240727D: Correction to the GRB name in GCN 36958
  59. GRB 240727A: Fermi GBM Final Real-time Localization
  60. GRB 240727C: AstroSat CZTI detection of a long burst
  61. GRB 240727A: Swift-XRT refined Analysis
  62. GRB 240720B: GRBAlpha detection
  63. GRB 240718A: GRBAlpha detection
  64. GRB 240710B: GRBAlpha detection
  65. GRB 240627A: GRBAlpha detection
  66. Fermi GRB 240726A: Global MASTER-Net observations report
  67. GRB 240727A: Enhanced Swift-XRT position
  68. GRB 240727B: Fermi GBM Observation
  69. GRB 240727B: Swift ToO observations
  70. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  71. GRB 240726A: SVOM/GRM observation
  72. GRB 240727B: AstroSat CZTI detection
  73. GRB 240726B: AstroSat CZTI detection of a short burst
  74. GRB240727A: Skynet Optical Afterglow Observations
  75. GRB 240727A: TRT optical afterglow detection
  76. GRB 240727A: KAIT Optical Afterglow Candidate
  77. GRB 240727A: Swift detection of a burst
  78. GRB 240726A: AstroSat CZTI detection of a short burst
  79. GRB 240726A: Fermi GBM Final Real-time Localization
  80. Fermi-LAT gamma-ray observations of IceCube-240725A
  81. IceCube-240725A - IceCube observation of a high-energy neutrino candidate track-like event
  82. Swift Trigger 1244778 is not a GRB
  83. GRB 240720A: Swift-BAT refined analysis
  84. Fermi trigger No 743418632: Global MASTER-Net observations report
  85. Fermi trigger No 743315411: Global MASTER-Net observations report
  86. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  87. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  88. Fermi trigger No 743345551: Global MASTER-Net observations report
  89. Fermi-LAT gamma-ray observations of IceCube-240721A
  90. Fermi Gamma-ray Burst Monitor trigger 743271526/240721680 is not a GRB
  91. Fermi trigger No 743219692: Global MASTER-Net observations report
  92. IceCube-240721A - IceCube observation of a high-energy neutrino candidate track-like event
  93. Fermi Gamma-ray Burst Monitor trigger 743243582/240721356 (GRB 240721A) is not a GRB
  94. GRB 240720B: SVOM/GRM observation
  95. GRB 240721A: Fermi GBM Final Real-time Localization
  96. GRB 240720B: AstroSat CZTI detection of a short burst
  97. Fermi GRB 240720A: Global MASTER-Net observations report
  98. GRB 240720A: AstroSat CZTI detection
  99. GRB 240720A: Fermi GBM observation
  100. GRB 240720A: Swift detection of a burst

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