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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"

8474 results found.

  1. GRB 100115A: Gemini-N photometry
  2. GRB 100115A: SARA Astrometry
  3. NOT observation of GRB100115A localization
  4. GRB 100115A: SARA Afterglow Candidate
  5. GRB 100115A: Swift/UVOT Upper Limits
  6. GRB 100115A: Swift-XRT candidate afterglow
  7. GRB 100111A: Swift-BAT refined analysis
  8. GRB 100111A: Swift detection of a burst with an optical afterglow
  9. GRB 100103A: Swift/UVOT Upper Limits
  10. GRB 091231: GROND NIR observations
  11. Trigger 381591: Swift detection of a possible burst
  12. GRB 091230: Swift-XRT observation
  13. GRB 091230: GROND optical/NIR afterglow candidate
  14. Trigger 381434: Swift detection of a possible burst
  15. GRB 091221: ROTSE-III Detection of Optical Counterpart
  16. GRB 091221: Swift detection of a burst
  17. Swift trigger 379449 (possible GRB) is not a burst
  18. Trigger 379449: Swift detection of a possible burst
  19. GRB 091208B: Swift detection of a burst with an optical afterglow
  20. GRB 091202: GTC & CAHA optical/nIR afterglow candidate
  21. GRB 091117: Chandra Observations
  22. Swift trigger 377436 (possible GRB 091130A) is not a burst
  23. GRB 091130B: Swift detection of a burst
  24. GRB 091130: Swift detection of a possible burst
  25. GRB 091127 : GROND observations
  26. GRB 091127: Swift/UVOT Detection of an Optical Afterglow
  27. GRB 091127: Liverpool Telescope afterglow candidate
  28. GRB091117: Gemini South Observations
  29. GRB 091109B: Swift detection of a short burst
  30. GRB 091109: Faulkes Telescope South observations
  31. GRB 091109: Swift detection of a burst with optical afterglow
  32. GRB 091104: Swift detection of a burst
  33. GRB 091102 : Faulkes Telescope South Upper Limits
  34. GRB 091102: GROND Upper Limits
  35. GRB 091102: Swift/XRT localization
  36. GRB 091102: Swift/UVOT Finding Chart Observation
  37. GRB 091024: optical observations
  38. GRB 091029: Gemini-South Redshift
  39. GRB 091029: Swift detection of a burst with an optical counterpart
  40. GRB 091026: Swift-BAT refined analysis
  41. GRB 091026: Swift detection of a Gamma Ray Burst
  42. GRB 091024: Swift-XRT team refined analysis
  43. GRB 091024: Faulkes Telescope North Afterglow Candidate
  44. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  45. GRB 091020: Swift detection of a burst with an optical afterglow
  46. GRB 091018: miniTAO/ANIR Observations
  47. GRB 091018 : Faulkes Telescope South Observations
  48. GRB 091018: GROND observations
  49. GRB 091018: ROTSE-III Detection of Optical Counterpart
  50. GRB 091018: Swift detection of a burst with optical afterglow
  51. Fwd: GRB 091003: Possible Supernova Component Retraction
  52. GRB 091003: Possible Supernova Component
  53. GRB 091010: optical obsevation
  54. GRB 091010: optical afterglow candidate rejection
  55. GRB 091010: Faulkes Telescope North observations
  56. GRB 091010: RXTE detection
  57. GRB 091010: Enhanced XRT position
  58. GRB 091010 optical upper limits
  59. GRB 091010: GROND afterglow candidate
  60. GRB 090910: SuperAGILE Localization of a Long GRB
  61. GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
  62. GRB 090929B: Gemini-N upper limits
  63. GRB 090929B: Swift detection of a burst
  64. GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
  65. GRB 090926B: VLT spectroscopy
  66. GRB 090927: Swift/UVOT detection of an optical afterglow
  67. GRB 090926A: Swift/UVOT detection of an optical afterglow
  68. GRB 090926B: Swift detection of a burst
  69. GRB 090925: Fermi GBM detection
  70. GRB 090915: SARA detection of afterglow candidate
  71. GRB 090912: optical observation
  72. GRB 090915: Swift/UVOT detection of an optical afterglow candidate
  73. GRB 090912: Swift detection of a burst
  74. GRB 090904A: Swift-BAT refined analysis
  75. GRB 090902B: WSRT Radio Observation
  76. GRB 090904B: Swift detection of a burst
  77. GRB 090904: Swift detection of a burst
  78. GRB 090902B: Faulkes Telescope North observations
  79. GRB 090902B: Optical afterglow candidate
  80. GRB090902B: Swift/UVOT observations
  81. GRB 090902B: Swift/XRT Afterglow Candidate
  82. GRB 090831C: Swift detection of a burst
  83. GRB 090831B: Swift detection of a possible burst
  84. Konus-Wind observations of GRB 090827
  85. GRB 090817 - TLS Observations
  86. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  87. GRB 090817: Swift-XRT observations
  88. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  89. GRB 090814: Swift detection of a burst
  90. GRB 090813: optical candidate from 1.23m CAHA telescope
  91. GRB 090813: Swift detection of a burst
  92. GRB 090812: Swift detection of a burst with an optical counterpart
  93. GRB 090809: Swift detection of a burst with a possible optical counterpart
  94. GRB 090807: Swift detection of a burst
  95. GRB 090802: Fermi GBM detection
  96. Swift trigger 358760 is probably a noise event
  97. GRB 090709A : Quick look analysis of the Suzaku observation
  98. GRB 090728A: Faulkes Telescope North Optical Afterglow Candidate
  99. GRB 090728: Swift detection of a burst
  100. GRB 090727: Swift-BAT refined analysis

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