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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"

21456 results found.

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

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