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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"

19590 results found.

  1. GRB 240805B: GIT optical upper limit
  2. GRB 240805B: Swift-BAT refined analysis
  3. GRB 240805A: Swift-BAT refined analysis
  4. Konus-Wind detection of GRB 240805A
  5. GRB 240805B Bassano Bresciano Observatory upper limit
  6. GRB240805A: Fermi GBM Observation
  7. GRB 240805B: JinShan optical afterglow detection
  8. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  9. GRB 240805B: Swift-XRT refined Analysis
  10. GRB 240805B: Swift/UVOT Upper Limits
  11. GRB 240805A: Swift/UVOT Upper Limits
  12. GRB 240805A: SVOM/GRM observation
  13. GRB 240805B: Enhanced Swift-XRT position
  14. GRB 240805B: LCOGT Optical Upper Limits
  15. Swift GRB 240805B: Global MASTER-Net observations report
  16. GRB 240805B: JinShan optical upper limits
  17. Swift GRB 240805A: Global MASTER-Net observations report
  18. GRB 240805A: Swift-XRT refined Analysis
  19. GRB 240805B: Swift detection of a burst
  20. GRB 240805A: Fermi-LAT detection
  21. GRB 240805A: INTEGRAL spectral analysis
  22. GRB 240805A: A long GRB detected by INTEGRAL
  23. GRB 240805A: Swift detection of a burst
  24. GRB 240730A: Swift-BAT refined analysis
  25. GRB240730A: BOOTES-5/JGT early optical upper limit
  26. Swift GRB 240730A: Global MASTER-Net observations report
  27. GRB 240730A: Swift-XRT refined Analysis
  28. GRB 240715A: Swift-XRT afterglow detection
  29. GRB 240730A: KAIT Optical Upper Limit
  30. GRB 240730A: Swift/UVOT Upper Limits
  31. GRB 240730A: Enhanced Swift-XRT position
  32. GRB 240730A: Swift detection of a burst
  33. GRB 240727A: Swift-BAT refined analysis
  34. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  35. GRB 240727A: observations of optical counterpart.
  36. GRB 240727B: Swift-XRT observations
  37. GRB 240727A: Swift/UVOT detection
  38. GRB 240727A: NOT optical observation
  39. GRB 240727A: JinShan optical upper limits
  40. GRB 240727A Bassano Bresciano Observatory upper limit
  41. GRB 240727A: Swift-XRT refined Analysis
  42. GRB 240727A: Enhanced Swift-XRT position
  43. GRB 240727B: Fermi GBM Observation
  44. Swift GRB240727.16: Global MASTER-Net observations report
  45. GRB 240727B: Swift ToO observations
  46. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  47. GRB240727A: Skynet Optical Afterglow Observations
  48. GRB 240727A: TRT optical afterglow detection
  49. GRB 240727A: KAIT Optical Afterglow Candidate
  50. GRB 240727A: Swift detection of a burst
  51. Swift Trigger 1244778 is not a GRB
  52. Swift GRB240725.11: Global MASTER-Net observations report
  53. GRB 240720A: Swift-BAT refined analysis
  54. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  55. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  56. GRB 240720A: AstroSat CZTI detection
  57. GRB 240720A: Fermi GBM observation
  58. GRB 240720A: Swift detection of a burst
  59. Swift GRB240720.02: Global MASTER-Net observations report
  60. GRB 240718A: Fermi-LAT Detection
  61. GRB 240712A: Swift-BAT refined analysis
  62. GRB 240715A: Swift/UVOT observations of the XRT sources.
  63. GRB 240715A: Swift-XRT observations
  64. GRB240713A: Swift/UVOT Upper LImits
  65. EP240708a: X-ray follow-up observations with Swift/XRT
  66. GRB 240713A: Swift-XRT observations
  67. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  68. GRB 240712A: Swift-XRT refined Analysis
  69. GRB 240715A: Swift ToO observations
  70. GRB 240712A ATCA radio observations
  71. IPN triangulation of GRB 240715A (short)
  72. GW s240422ed: Swift UVOT follow-up
  73. GRB 240712A: Swift/UVOT Upper Limits
  74. The EP-WXT source triggered on July 14th is likely a flaring star
  75. GRB 240713A: Tiled Swift observations
  76. GRB 240712A: Swift detection of a burst
  77. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  78. EP240708a: EP-WXT detection of a fast X-ray transient
  79. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  80. IPN triangulation of GRB 240628B (short)
  81. EP240703a and EP240703b: Swift/XRT upper limits
  82. EP240703c: Kinder optical follow-up and Swift XRT observations
  83. EP240703c: EP-WXT detection of an X-ray transient
  84. IPN triangulation of GRB 240627A
  85. EP240703b: EP-WXT detection of a fast X-ray transient
  86. EP240702a: Swift/XRT upper limit
  87. EP240703a: EP-WXT detection of a fast X-ray transient
  88. EP240702a: EP-WXT detection of a fast X-ray transient
  89. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  90. IPN triangulation of GRB 240619C
  91. GRB 240624A: Swift-BAT refined analysis
  92. Konus-Wind detection of GRB 240619A
  93. GRB240624A: Fermi GBM Observation
  94. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  95. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  96. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  97. Swift GRB 240624A: Global MASTER-Net observations report
  98. GRB 240624A: Swift detection of a burst
  99. GRB 240529A: JinShan optical observations
  100. IPN triangulation of GRB 240615A (short)

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