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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"

19589 results found.

  1. GRB 240809A: SVOM/GRM observation
  2. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  3. GRB 240805A: ATCA Radio Upper Limits
  4. GRB 240805B: GIT optical upper limit
  5. GRB 240805B: Swift-BAT refined analysis
  6. GRB 240805A: Swift-BAT refined analysis
  7. Konus-Wind detection of GRB 240805A
  8. GRB 240805B Bassano Bresciano Observatory upper limit
  9. GRB240805A: Fermi GBM Observation
  10. GRB 240805B: JinShan optical afterglow detection
  11. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  12. GRB 240805B: Swift-XRT refined Analysis
  13. GRB 240805B: Swift/UVOT Upper Limits
  14. GRB 240805A: Swift/UVOT Upper Limits
  15. GRB 240805A: SVOM/GRM observation
  16. GRB 240805B: Enhanced Swift-XRT position
  17. GRB 240805B: LCOGT Optical Upper Limits
  18. Swift GRB 240805B: Global MASTER-Net observations report
  19. GRB 240805B: JinShan optical upper limits
  20. Swift GRB 240805A: Global MASTER-Net observations report
  21. GRB 240805A: Swift-XRT refined Analysis
  22. GRB 240805B: Swift detection of a burst
  23. GRB 240805A: Fermi-LAT detection
  24. GRB 240805A: INTEGRAL spectral analysis
  25. GRB 240805A: A long GRB detected by INTEGRAL
  26. GRB 240805A: Swift detection of a burst
  27. GRB 240730A: Swift-BAT refined analysis
  28. GRB240730A: BOOTES-5/JGT early optical upper limit
  29. Swift GRB 240730A: Global MASTER-Net observations report
  30. GRB 240730A: Swift-XRT refined Analysis
  31. GRB 240715A: Swift-XRT afterglow detection
  32. GRB 240730A: KAIT Optical Upper Limit
  33. GRB 240730A: Swift/UVOT Upper Limits
  34. GRB 240730A: Enhanced Swift-XRT position
  35. GRB 240730A: Swift detection of a burst
  36. GRB 240727A: Swift-BAT refined analysis
  37. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  38. GRB 240727A: observations of optical counterpart.
  39. GRB 240727B: Swift-XRT observations
  40. GRB 240727A: Swift/UVOT detection
  41. GRB 240727A: NOT optical observation
  42. GRB 240727A: JinShan optical upper limits
  43. GRB 240727A Bassano Bresciano Observatory upper limit
  44. GRB 240727A: Swift-XRT refined Analysis
  45. GRB 240727A: Enhanced Swift-XRT position
  46. GRB 240727B: Fermi GBM Observation
  47. Swift GRB240727.16: Global MASTER-Net observations report
  48. GRB 240727B: Swift ToO observations
  49. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  50. GRB240727A: Skynet Optical Afterglow Observations
  51. GRB 240727A: TRT optical afterglow detection
  52. GRB 240727A: KAIT Optical Afterglow Candidate
  53. GRB 240727A: Swift detection of a burst
  54. Swift Trigger 1244778 is not a GRB
  55. Swift GRB240725.11: Global MASTER-Net observations report
  56. GRB 240720A: Swift-BAT refined analysis
  57. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  58. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  59. GRB 240720A: AstroSat CZTI detection
  60. GRB 240720A: Fermi GBM observation
  61. GRB 240720A: Swift detection of a burst
  62. Swift GRB240720.02: Global MASTER-Net observations report
  63. GRB 240718A: Fermi-LAT Detection
  64. GRB 240712A: Swift-BAT refined analysis
  65. GRB 240715A: Swift/UVOT observations of the XRT sources.
  66. GRB 240715A: Swift-XRT observations
  67. GRB240713A: Swift/UVOT Upper LImits
  68. EP240708a: X-ray follow-up observations with Swift/XRT
  69. GRB 240713A: Swift-XRT observations
  70. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  71. GRB 240712A: Swift-XRT refined Analysis
  72. GRB 240715A: Swift ToO observations
  73. GRB 240712A ATCA radio observations
  74. IPN triangulation of GRB 240715A (short)
  75. GW s240422ed: Swift UVOT follow-up
  76. GRB 240712A: Swift/UVOT Upper Limits
  77. The EP-WXT source triggered on July 14th is likely a flaring star
  78. GRB 240713A: Tiled Swift observations
  79. GRB 240712A: Swift detection of a burst
  80. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  81. EP240708a: EP-WXT detection of a fast X-ray transient
  82. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  83. IPN triangulation of GRB 240628B (short)
  84. EP240703a and EP240703b: Swift/XRT upper limits
  85. EP240703c: Kinder optical follow-up and Swift XRT observations
  86. EP240703c: EP-WXT detection of an X-ray transient
  87. IPN triangulation of GRB 240627A
  88. EP240703b: EP-WXT detection of a fast X-ray transient
  89. EP240702a: Swift/XRT upper limit
  90. EP240703a: EP-WXT detection of a fast X-ray transient
  91. EP240702a: EP-WXT detection of a fast X-ray transient
  92. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  93. IPN triangulation of GRB 240619C
  94. GRB 240624A: Swift-BAT refined analysis
  95. Konus-Wind detection of GRB 240619A
  96. GRB240624A: Fermi GBM Observation
  97. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  98. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  99. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  100. Swift GRB 240624A: Global MASTER-Net observations report

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