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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"

19596 results found.

  1. GRB 240809A: Swift-XRT refined Analysis
  2. IPN triangulation of GRB 240807A / EP 240807a
  3. Swift GRB 240809A: Global MASTER-Net observations report
  4. GRB 240809A: JinShan optical observations
  5. GRB 240809A: Enhanced Swift-XRT position
  6. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  7. GRB 240809A: SVOM/GRM observation
  8. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  9. GRB 240805A: ATCA Radio Upper Limits
  10. GRB 240805B: GIT optical upper limit
  11. GRB 240805B: Swift-BAT refined analysis
  12. GRB 240805A: Swift-BAT refined analysis
  13. Konus-Wind detection of GRB 240805A
  14. GRB 240805B Bassano Bresciano Observatory upper limit
  15. GRB240805A: Fermi GBM Observation
  16. GRB 240805B: JinShan optical afterglow detection
  17. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  18. GRB 240805B: Swift-XRT refined Analysis
  19. GRB 240805B: Swift/UVOT Upper Limits
  20. GRB 240805A: Swift/UVOT Upper Limits
  21. GRB 240805A: SVOM/GRM observation
  22. GRB 240805B: Enhanced Swift-XRT position
  23. GRB 240805B: LCOGT Optical Upper Limits
  24. Swift GRB 240805B: Global MASTER-Net observations report
  25. GRB 240805B: JinShan optical upper limits
  26. Swift GRB 240805A: Global MASTER-Net observations report
  27. GRB 240805A: Swift-XRT refined Analysis
  28. GRB 240805B: Swift detection of a burst
  29. GRB 240805A: Fermi-LAT detection
  30. GRB 240805A: INTEGRAL spectral analysis
  31. GRB 240805A: A long GRB detected by INTEGRAL
  32. GRB 240805A: Swift detection of a burst
  33. GRB 240730A: Swift-BAT refined analysis
  34. GRB240730A: BOOTES-5/JGT early optical upper limit
  35. Swift GRB 240730A: Global MASTER-Net observations report
  36. GRB 240730A: Swift-XRT refined Analysis
  37. GRB 240715A: Swift-XRT afterglow detection
  38. GRB 240730A: KAIT Optical Upper Limit
  39. GRB 240730A: Swift/UVOT Upper Limits
  40. GRB 240730A: Enhanced Swift-XRT position
  41. GRB 240730A: Swift detection of a burst
  42. GRB 240727A: Swift-BAT refined analysis
  43. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  44. GRB 240727A: observations of optical counterpart.
  45. GRB 240727B: Swift-XRT observations
  46. GRB 240727A: Swift/UVOT detection
  47. GRB 240727A: NOT optical observation
  48. GRB 240727A: JinShan optical upper limits
  49. GRB 240727A Bassano Bresciano Observatory upper limit
  50. GRB 240727A: Swift-XRT refined Analysis
  51. GRB 240727A: Enhanced Swift-XRT position
  52. GRB 240727B: Fermi GBM Observation
  53. Swift GRB240727.16: Global MASTER-Net observations report
  54. GRB 240727B: Swift ToO observations
  55. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  56. GRB240727A: Skynet Optical Afterglow Observations
  57. GRB 240727A: TRT optical afterglow detection
  58. GRB 240727A: KAIT Optical Afterglow Candidate
  59. GRB 240727A: Swift detection of a burst
  60. Swift Trigger 1244778 is not a GRB
  61. Swift GRB240725.11: Global MASTER-Net observations report
  62. GRB 240720A: Swift-BAT refined analysis
  63. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  64. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  65. GRB 240720A: AstroSat CZTI detection
  66. GRB 240720A: Fermi GBM observation
  67. GRB 240720A: Swift detection of a burst
  68. Swift GRB240720.02: Global MASTER-Net observations report
  69. GRB 240718A: Fermi-LAT Detection
  70. GRB 240712A: Swift-BAT refined analysis
  71. GRB 240715A: Swift/UVOT observations of the XRT sources.
  72. GRB 240715A: Swift-XRT observations
  73. GRB240713A: Swift/UVOT Upper LImits
  74. EP240708a: X-ray follow-up observations with Swift/XRT
  75. GRB 240713A: Swift-XRT observations
  76. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  77. GRB 240712A: Swift-XRT refined Analysis
  78. GRB 240715A: Swift ToO observations
  79. GRB 240712A ATCA radio observations
  80. IPN triangulation of GRB 240715A (short)
  81. GW s240422ed: Swift UVOT follow-up
  82. GRB 240712A: Swift/UVOT Upper Limits
  83. The EP-WXT source triggered on July 14th is likely a flaring star
  84. GRB 240713A: Tiled Swift observations
  85. GRB 240712A: Swift detection of a burst
  86. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  87. EP240708a: EP-WXT detection of a fast X-ray transient
  88. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  89. IPN triangulation of GRB 240628B (short)
  90. EP240703a and EP240703b: Swift/XRT upper limits
  91. EP240703c: Kinder optical follow-up and Swift XRT observations
  92. EP240703c: EP-WXT detection of an X-ray transient
  93. IPN triangulation of GRB 240627A
  94. EP240703b: EP-WXT detection of a fast X-ray transient
  95. EP240702a: Swift/XRT upper limit
  96. EP240703a: EP-WXT detection of a fast X-ray transient
  97. EP240702a: EP-WXT detection of a fast X-ray transient
  98. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  99. IPN triangulation of GRB 240619C
  100. GRB 240624A: Swift-BAT refined analysis

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