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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"

38258 results found.

  1. GRB 240624B: VZLUSAT-2 detection
  2. GRB 240619C: VZLUSAT-2 detection
  3. EP 240806A: LCO optical observations
  4. GRB 240805B: Optical detection with 1.6m Mephisto
  5. GRB 240805B: NUTTelA-TAO / BSTI Optical Limits
  6. GRB 240805B: Swift-XRT refined Analysis
  7. Fermi trigger No 744544656: Global MASTER-Net observations report
  8. GRB 240805B: Swift/UVOT Upper Limits
  9. GRB 240805A: Swift/UVOT Upper Limits
  10. GRB 240805B: BTA optical afterglow candidate
  11. GRB 240805A: SVOM/GRM observation
  12. GRB 240805B: Enhanced Swift-XRT position
  13. GRB 240805B: LCOGT Optical Upper Limits
  14. Swift GRB 240805B: Global MASTER-Net observations report
  15. GRB 240805B: JinShan optical upper limits
  16. Fermi GRB 240805A: Global MASTER-Net observations report
  17. Swift GRB 240805A: Global MASTER-Net observations report
  18. Fermi Gamma-ray Burst Monitor trigger 744558410/240805574 is not a GRB
  19. GRB 240805A: Swift-XRT refined Analysis
  20. EP240804a: GSP detects optical candidate counterpart
  21. GRB 240805B: Swift detection of a burst
  22. GRB 240805A: Fermi-LAT detection
  23. GRB 240805A: INTEGRAL spectral analysis
  24. EP240801a: Continued optical observations at ZTSh (CraO)
  25. EP240804a: LCOGT optical counterpart detection
  26. GRB 240805A: A long GRB detected by INTEGRAL
  27. EP240804a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  28. GRB 240805A: Swift detection of a burst
  29. GRB 240805A: Fermi GBM Final Real-time Localization
  30. Fermi GRB 240804A: Global MASTER-Net observations report
  31. EP240802a: Montarrenti Observatory optical upper limit
  32. GRB 240804A: Fermi GBM Final Real-time Localization
  33. Fermi trigger No 744459130: Global MASTER-Net observations report
  34. IPN triangulation of GRB 240802A / EP 240802a
  35. Fermi Gamma-ray Burst Monitor trigger 744459130/240804425 is not a GRB
  36. EP240802A: Bassano Bresciano Observatory upper limit
  37. GRB 240802A: SVOM/GRM observation
  38. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  39. Fermi trigger No 744278264: Global MASTER-Net observations report
  40. GRB 240802A: AstroSat CZTI detection of a long burst
  41. EP240801a: further SAO RAS optical observations
  42. EP240801a: optical observations at CrAO and AbAO
  43. EP240801a: Leavitt Observatory optical observations
  44. EP240801a: GTC spectroscopy and absorption redshift
  45. EP240801a: SAO RAS optical observations
  46. GRB 240801B: AstroSat CZTI Updated classification - likely a solar flare
  47. EP240801a: JinShan optical observations
  48. GRB 240727C: SVOM/GRM observation
  49. EP240801a: follow-up observation with LCOGT
  50. Fermi GBM trigger 744179961 / 240801194 can not be confirmed as a GRB
  51. GRB 240730A: Swift-BAT refined analysis
  52. EP240801a: GSP follow-up observations of the candidate counterpart
  53. Fermi trigger No 744204856: Global MASTER-Net observations report
  54. EP240801a: KAIT optical counterpart observations
  55. EP240801a: TRT optical counterpart detection
  56. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  57. GRB 240801B: AstroSat CZTI detection of a bright long burst
  58. Fermi GRB 240801A: Global MASTER-Net observations report
  59. GRB 240801A: Fermi GBM Final Real-time Localization
  60. GRB 240730C: AstroSat CZTI detection of a long burst
  61. GRB 240731A: Fermi GBM Final Localization
  62. Fermi trigger No 744128417: Global MASTER-Net observations report
  63. Fermi trigger No 744083370: Global MASTER-Net observations report
  64. GRB 240731A: AstroSat CZTI detection
  65. GRB 240730A: Osservatorio Astronomico Nastro Verde upper limit
  66. GRB240730A: BOOTES-5/JGT early optical upper limit
  67. Fermi Gamma-ray Burst Monitor trigger 744061103/240730818 is not a GRB
  68. Fermi GRB 240730B: Global MASTER-Net observations report
  69. GRB 240730B: Fermi GBM Final Real-time Localization
  70. Swift GRB 240730A: Global MASTER-Net observations report
  71. GRB 240730A: Swift-XRT refined Analysis
  72. GRB 240715A: Swift-XRT afterglow detection
  73. GRB 240730A: KAIT Optical Upper Limit
  74. GRB 240727C: GRBAlpha detection
  75. GRB 240730A: Swift/UVOT Upper Limits
  76. GRB 240730A: Enhanced Swift-XRT position
  77. GRB 240730A: Swift detection of a burst
  78. Fermi trigger No 743953682: Global MASTER-Net observations report
  79. GRB 240727A: Swift-BAT refined analysis
  80. Fermi Gamma-ray Burst Monitor trigger 743953682/240729575 is not a GRB
  81. GRB 240727A: observations of optical counterpart.
  82. GRB 240727B: Swift-XRT observations
  83. Fermi GRB 240727A: Global MASTER-Net observations report
  84. GRB 240727A: Swift/UVOT detection
  85. Fermi trigger No 743868421: Global MASTER-Net observations report
  86. Fermi Gamma-ray Burst Monitor trigger 743868421/240728588 is not a GRB
  87. GRB 240727A: Correction to time in GCN36960
  88. GRB 240727A: Osservatorio Astronomico Nastro Verde upper limit
  89. GRB 240727A: NOT optical observation
  90. GRB 240727A: JinShan optical upper limits
  91. GRB 240727A Bassano Bresciano Observatory upper limit
  92. GRB 240727D: Correction to the GRB name in GCN 36958
  93. GRB 240727A: Fermi GBM Final Real-time Localization
  94. GRB 240727C: AstroSat CZTI detection of a long burst
  95. GRB 240727A: Swift-XRT refined Analysis
  96. GRB 240720B: GRBAlpha detection
  97. GRB 240718A: GRBAlpha detection
  98. GRB 240710B: GRBAlpha detection
  99. GRB 240627A: GRBAlpha detection
  100. Fermi GRB 240726A: Global MASTER-Net observations report

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