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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"

19173 results found.

  1. GRB 240805B: Swift detection of a burst
  2. GRB 240805A: Fermi-LAT detection
  3. GRB 240805A: INTEGRAL spectral analysis
  4. GRB 240805A: A long GRB detected by INTEGRAL
  5. GRB 240805A: Swift detection of a burst
  6. GRB 240730A: Swift-BAT refined analysis
  7. GRB240730A: BOOTES-5/JGT early optical upper limit
  8. Swift GRB 240730A: Global MASTER-Net observations report
  9. GRB 240730A: Swift-XRT refined Analysis
  10. GRB 240715A: Swift-XRT afterglow detection
  11. GRB 240730A: KAIT Optical Upper Limit
  12. GRB 240730A: Swift/UVOT Upper Limits
  13. GRB 240730A: Enhanced Swift-XRT position
  14. GRB 240730A: Swift detection of a burst
  15. GRB 240727A: Swift-BAT refined analysis
  16. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  17. GRB 240727A: observations of optical counterpart.
  18. GRB 240727B: Swift-XRT observations
  19. GRB 240727A: Swift/UVOT detection
  20. GRB 240727A: NOT optical observation
  21. GRB 240727A: JinShan optical upper limits
  22. GRB 240727A Bassano Bresciano Observatory upper limit
  23. GRB 240727A: Swift-XRT refined Analysis
  24. GRB 240727A: Enhanced Swift-XRT position
  25. GRB 240727B: Fermi GBM Observation
  26. Swift GRB240727.16: Global MASTER-Net observations report
  27. GRB 240727B: Swift ToO observations
  28. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  29. GRB240727A: Skynet Optical Afterglow Observations
  30. GRB 240727A: TRT optical afterglow detection
  31. GRB 240727A: KAIT Optical Afterglow Candidate
  32. GRB 240727A: Swift detection of a burst
  33. Swift Trigger 1244778 is not a GRB
  34. Swift GRB240725.11: Global MASTER-Net observations report
  35. GRB 240720A: Swift-BAT refined analysis
  36. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  37. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  38. GRB 240720A: AstroSat CZTI detection
  39. GRB 240720A: Fermi GBM observation
  40. GRB 240720A: Swift detection of a burst
  41. Swift GRB240720.02: Global MASTER-Net observations report
  42. GRB 240718A: Fermi-LAT Detection
  43. GRB 240712A: Swift-BAT refined analysis
  44. GRB 240715A: Swift/UVOT observations of the XRT sources.
  45. GRB 240715A: Swift-XRT observations
  46. GRB240713A: Swift/UVOT Upper LImits
  47. EP240708a: X-ray follow-up observations with Swift/XRT
  48. GRB 240713A: Swift-XRT observations
  49. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  50. GRB 240712A: Swift-XRT refined Analysis
  51. GRB 240715A: Swift ToO observations
  52. GRB 240712A ATCA radio observations
  53. IPN triangulation of GRB 240715A (short)
  54. GW s240422ed: Swift UVOT follow-up
  55. GRB 240712A: Swift/UVOT Upper Limits
  56. The EP-WXT source triggered on July 14th is likely a flaring star
  57. GRB 240713A: Tiled Swift observations
  58. GRB 240712A: Swift detection of a burst
  59. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  60. EP240708a: EP-WXT detection of a fast X-ray transient
  61. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  62. IPN triangulation of GRB 240628B (short)
  63. EP240703a and EP240703b: Swift/XRT upper limits
  64. EP240703c: Kinder optical follow-up and Swift XRT observations
  65. EP240703c: EP-WXT detection of an X-ray transient
  66. IPN triangulation of GRB 240627A
  67. EP240703b: EP-WXT detection of a fast X-ray transient
  68. EP240702a: Swift/XRT upper limit
  69. EP240703a: EP-WXT detection of a fast X-ray transient
  70. EP240702a: EP-WXT detection of a fast X-ray transient
  71. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  72. IPN triangulation of GRB 240619C
  73. GRB 240624A: Swift-BAT refined analysis
  74. Konus-Wind detection of GRB 240619A
  75. GRB240624A: Fermi GBM Observation
  76. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  77. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  78. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  79. Swift GRB 240624A: Global MASTER-Net observations report
  80. GRB 240624A: Swift detection of a burst
  81. GRB 240529A: JinShan optical observations
  82. IPN triangulation of GRB 240615A (short)
  83. EP240618a: Swift/XRT upper limit
  84. EP240617a: tentative Swift/XRT detection of the afterglow
  85. GRB 240619A: Swift-XRT probable afterglow detection
  86. GRB 240619A: Swift ToO observations
  87. GRB 240615A: NOT optical observations
  88. GRB 240615A: possible transient detection from Wendelstein observations
  89. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  90. GRB240615A: 1.3m DFOT optical upper limit
  91. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  92. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  93. GRB 240615A: J-band upper limits from WINTER
  94. GRB 240615A: Fermi GBM Observation
  95. GRB 240615A: Swift-XRT observations
  96. GRB 240615A: GECAM detection
  97. GRB 240615A: FLWO-1.2m optical upper limits
  98. Konus-Wind detection of GRB 240615A (short/hard)
  99. GRB 240615A: GOTO optical upper limits
  100. GRB 240615A: Swift ToO observations

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