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

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