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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"

19603 results found.

  1. GRB 240809A: KAIT optical observations
  2. GRB 240809A: GIT afterglow observations
  3. GRB 240809A: Swift/UVOT Detection
  4. GRB 240809A: Swift-XRT refined Analysis
  5. IPN triangulation of GRB 240807A / EP 240807a
  6. Swift GRB 240809A: Global MASTER-Net observations report
  7. GRB 240809A: JinShan optical observations
  8. GRB 240809A: Enhanced Swift-XRT position
  9. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  10. GRB 240809A: SVOM/GRM observation
  11. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  12. GRB 240805A: ATCA Radio Upper Limits
  13. GRB 240805B: GIT optical upper limit
  14. GRB 240805B: Swift-BAT refined analysis
  15. GRB 240805A: Swift-BAT refined analysis
  16. Konus-Wind detection of GRB 240805A
  17. GRB 240805B Bassano Bresciano Observatory upper limit
  18. GRB240805A: Fermi GBM Observation
  19. GRB 240805B: JinShan optical afterglow detection
  20. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  21. GRB 240805B: Swift-XRT refined Analysis
  22. GRB 240805B: Swift/UVOT Upper Limits
  23. GRB 240805A: Swift/UVOT Upper Limits
  24. GRB 240805A: SVOM/GRM observation
  25. GRB 240805B: Enhanced Swift-XRT position
  26. GRB 240805B: LCOGT Optical Upper Limits
  27. Swift GRB 240805B: Global MASTER-Net observations report
  28. GRB 240805B: JinShan optical upper limits
  29. Swift GRB 240805A: Global MASTER-Net observations report
  30. GRB 240805A: Swift-XRT refined Analysis
  31. GRB 240805B: Swift detection of a burst
  32. GRB 240805A: Fermi-LAT detection
  33. GRB 240805A: INTEGRAL spectral analysis
  34. GRB 240805A: A long GRB detected by INTEGRAL
  35. GRB 240805A: Swift detection of a burst
  36. GRB 240730A: Swift-BAT refined analysis
  37. GRB240730A: BOOTES-5/JGT early optical upper limit
  38. Swift GRB 240730A: Global MASTER-Net observations report
  39. GRB 240730A: Swift-XRT refined Analysis
  40. GRB 240715A: Swift-XRT afterglow detection
  41. GRB 240730A: KAIT Optical Upper Limit
  42. GRB 240730A: Swift/UVOT Upper Limits
  43. GRB 240730A: Enhanced Swift-XRT position
  44. GRB 240730A: Swift detection of a burst
  45. GRB 240727A: Swift-BAT refined analysis
  46. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  47. GRB 240727A: observations of optical counterpart.
  48. GRB 240727B: Swift-XRT observations
  49. GRB 240727A: Swift/UVOT detection
  50. GRB 240727A: NOT optical observation
  51. GRB 240727A: JinShan optical upper limits
  52. GRB 240727A Bassano Bresciano Observatory upper limit
  53. GRB 240727A: Swift-XRT refined Analysis
  54. GRB 240727A: Enhanced Swift-XRT position
  55. GRB 240727B: Fermi GBM Observation
  56. Swift GRB240727.16: Global MASTER-Net observations report
  57. GRB 240727B: Swift ToO observations
  58. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  59. GRB240727A: Skynet Optical Afterglow Observations
  60. GRB 240727A: TRT optical afterglow detection
  61. GRB 240727A: KAIT Optical Afterglow Candidate
  62. GRB 240727A: Swift detection of a burst
  63. Swift Trigger 1244778 is not a GRB
  64. Swift GRB240725.11: Global MASTER-Net observations report
  65. GRB 240720A: Swift-BAT refined analysis
  66. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  67. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  68. GRB 240720A: AstroSat CZTI detection
  69. GRB 240720A: Fermi GBM observation
  70. GRB 240720A: Swift detection of a burst
  71. Swift GRB240720.02: Global MASTER-Net observations report
  72. GRB 240718A: Fermi-LAT Detection
  73. GRB 240712A: Swift-BAT refined analysis
  74. GRB 240715A: Swift/UVOT observations of the XRT sources.
  75. GRB 240715A: Swift-XRT observations
  76. GRB240713A: Swift/UVOT Upper LImits
  77. EP240708a: X-ray follow-up observations with Swift/XRT
  78. GRB 240713A: Swift-XRT observations
  79. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  80. GRB 240712A: Swift-XRT refined Analysis
  81. GRB 240715A: Swift ToO observations
  82. GRB 240712A ATCA radio observations
  83. IPN triangulation of GRB 240715A (short)
  84. GW s240422ed: Swift UVOT follow-up
  85. GRB 240712A: Swift/UVOT Upper Limits
  86. The EP-WXT source triggered on July 14th is likely a flaring star
  87. GRB 240713A: Tiled Swift observations
  88. GRB 240712A: Swift detection of a burst
  89. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  90. EP240708a: EP-WXT detection of a fast X-ray transient
  91. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  92. IPN triangulation of GRB 240628B (short)
  93. EP240703a and EP240703b: Swift/XRT upper limits
  94. EP240703c: Kinder optical follow-up and Swift XRT observations
  95. EP240703c: EP-WXT detection of an X-ray transient
  96. IPN triangulation of GRB 240627A
  97. EP240703b: EP-WXT detection of a fast X-ray transient
  98. EP240702a: Swift/XRT upper limit
  99. EP240703a: EP-WXT detection of a fast X-ray transient
  100. EP240702a: EP-WXT detection of a fast X-ray transient

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