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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"

19935 results found.

  1. Konus-Wind detection of GRB 240811A
  2. GRB 240811A: Swift-BAT refined analysis
  3. GRB 240809A: Swift-BAT refined analysis
  4. GRB 240811A: Bassano Bresciano Observatory upper limit
  5. GRB 240811A: Swift-XRT refined Analysis
  6. GRB 240811A: Swift/UVOT Upper Limits
  7. GRB 240811A: LCOGT Optical Upper Limit
  8. GRB 240811A: Enhanced Swift-XRT position
  9. Konus-Wind detection of GRB 240809A
  10. Swift GRB 240811A: Global MASTER-Net observations report
  11. GRB 240811A: Swift detection of a burst
  12. GRB 240809A: Bassano Bresciano Observatory optical observations
  13. GRB 240809A: KAIT optical observations
  14. GRB 240809A: GIT afterglow observations
  15. GRB 240809A: Swift/UVOT Detection
  16. GRB 240809A: Swift-XRT refined Analysis
  17. IPN triangulation of GRB 240807A / EP 240807a
  18. Swift GRB 240809A: Global MASTER-Net observations report
  19. GRB 240809A: JinShan optical observations
  20. GRB 240809A: Enhanced Swift-XRT position
  21. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  22. GRB 240809A: SVOM/GRM observation
  23. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  24. GRB 240805A: ATCA Radio Upper Limits
  25. GRB 240805B: GIT optical upper limit
  26. GRB 240805B: Swift-BAT refined analysis
  27. GRB 240805A: Swift-BAT refined analysis
  28. Konus-Wind detection of GRB 240805A
  29. GRB 240805B Bassano Bresciano Observatory upper limit
  30. GRB240805A: Fermi GBM Observation
  31. GRB 240805B: JinShan optical afterglow detection
  32. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  33. GRB 240805B: Swift-XRT refined Analysis
  34. GRB 240805B: Swift/UVOT Upper Limits
  35. GRB 240805A: Swift/UVOT Upper Limits
  36. GRB 240805A: SVOM/GRM observation
  37. GRB 240805B: Enhanced Swift-XRT position
  38. GRB 240805B: LCOGT Optical Upper Limits
  39. Swift GRB 240805B: Global MASTER-Net observations report
  40. GRB 240805B: JinShan optical upper limits
  41. Swift GRB 240805A: Global MASTER-Net observations report
  42. GRB 240805A: Swift-XRT refined Analysis
  43. GRB 240805B: Swift detection of a burst
  44. GRB 240805A: Fermi-LAT detection
  45. GRB 240805A: INTEGRAL spectral analysis
  46. GRB 240805A: A long GRB detected by INTEGRAL
  47. GRB 240805A: Swift detection of a burst
  48. GRB 240730A: Swift-BAT refined analysis
  49. GRB240730A: BOOTES-5/JGT early optical upper limit
  50. Swift GRB 240730A: Global MASTER-Net observations report
  51. GRB 240730A: Swift-XRT refined Analysis
  52. GRB 240715A: Swift-XRT afterglow detection
  53. GRB 240730A: KAIT Optical Upper Limit
  54. GRB 240730A: Swift/UVOT Upper Limits
  55. GRB 240730A: Enhanced Swift-XRT position
  56. GRB 240730A: Swift detection of a burst
  57. GRB 240727A: Swift-BAT refined analysis
  58. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  59. GRB 240727A: observations of optical counterpart.
  60. GRB 240727B: Swift-XRT observations
  61. GRB 240727A: Swift/UVOT detection
  62. GRB 240727A: NOT optical observation
  63. GRB 240727A: JinShan optical upper limits
  64. GRB 240727A Bassano Bresciano Observatory upper limit
  65. GRB 240727A: Swift-XRT refined Analysis
  66. GRB 240727A: Enhanced Swift-XRT position
  67. GRB 240727B: Fermi GBM Observation
  68. Swift GRB240727.16: Global MASTER-Net observations report
  69. GRB 240727B: Swift ToO observations
  70. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  71. GRB240727A: Skynet Optical Afterglow Observations
  72. GRB 240727A: TRT optical afterglow detection
  73. GRB 240727A: KAIT Optical Afterglow Candidate
  74. GRB 240727A: Swift detection of a burst
  75. Swift Trigger 1244778 is not a GRB
  76. Swift GRB240725.11: Global MASTER-Net observations report
  77. GRB 240720A: Swift-BAT refined analysis
  78. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  79. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  80. GRB 240720A: AstroSat CZTI detection
  81. GRB 240720A: Fermi GBM observation
  82. GRB 240720A: Swift detection of a burst
  83. Swift GRB240720.02: Global MASTER-Net observations report
  84. GRB 240718A: Fermi-LAT Detection
  85. GRB 240712A: Swift-BAT refined analysis
  86. GRB 240715A: Swift/UVOT observations of the XRT sources.
  87. GRB 240715A: Swift-XRT observations
  88. GRB240713A: Swift/UVOT Upper LImits
  89. EP240708a: X-ray follow-up observations with Swift/XRT
  90. GRB 240713A: Swift-XRT observations
  91. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  92. GRB 240712A: Swift-XRT refined Analysis
  93. GRB 240715A: Swift ToO observations
  94. GRB 240712A ATCA radio observations
  95. IPN triangulation of GRB 240715A (short)
  96. GW s240422ed: Swift UVOT follow-up
  97. GRB 240712A: Swift/UVOT Upper Limits
  98. The EP-WXT source triggered on July 14th is likely a flaring star
  99. GRB 240713A: Tiled Swift observations
  100. GRB 240712A: Swift detection of a burst

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