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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"

7417 results found.

  1. GRB 091020: Swift detection of a burst with an optical afterglow
  2. GRB 091018: miniTAO/ANIR Observations
  3. GRB 091018 : Faulkes Telescope South Observations
  4. GRB 091018: GROND observations
  5. GRB 091018: ROTSE-III Detection of Optical Counterpart
  6. GRB 091018: Swift detection of a burst with optical afterglow
  7. GRB 091003: Possible Supernova Component
  8. GRB 091010: optical obsevation
  9. GRB 091010: optical afterglow candidate rejection
  10. GRB 091010: Faulkes Telescope North observations
  11. GRB 091010: Enhanced XRT position
  12. GRB 091010 optical upper limits
  13. GRB 091010: GROND afterglow candidate
  14. GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
  15. GRB 090929B: Gemini-N upper limits
  16. GRB 090929B: Swift detection of a burst
  17. GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
  18. GRB 090926B: VLT spectroscopy
  19. GRB 090927: Swift/UVOT detection of an optical afterglow
  20. GRB 090926A: Swift/UVOT detection of an optical afterglow
  21. GRB 090926B: Swift detection of a burst
  22. GRB 090915: SARA detection of afterglow candidate
  23. GRB 090912: optical observation
  24. GRB 090915: Swift/UVOT detection of an optical afterglow candidate
  25. GRB 090912: Swift detection of a burst
  26. GRB 090904B: Swift detection of a burst
  27. GRB 090904: Swift detection of a burst
  28. GRB 090902B: Faulkes Telescope North observations
  29. GRB 090902B: Optical afterglow candidate
  30. GRB090902B: Swift/UVOT observations
  31. GRB 090902B: Swift/XRT Afterglow Candidate
  32. GRB 090831C: Swift detection of a burst
  33. GRB 090831B: Swift detection of a possible burst
  34. GRB 090817 - TLS Observations
  35. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  36. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  37. GRB 090814: Swift detection of a burst
  38. GRB 090813: optical candidate from 1.23m CAHA telescope
  39. GRB 090813: Swift detection of a burst
  40. GRB 090812: Swift detection of a burst with an optical counterpart
  41. GRB 090809: Swift detection of a burst with a possible optical counterpart
  42. GRB 090807: Swift detection of a burst
  43. Swift trigger 358760 is probably a noise event
  44. GRB 090728A: Faulkes Telescope North Optical Afterglow Candidate
  45. GRB 090728: Swift detection of a burst
  46. GRB 090727: Liverpool Telescope possible OT candidate
  47. GRB 090727: Swift detection of a burst
  48. GRB 090726: Afterglow candidate photometryfrom Crni Vrh
  49. GRB 090726: optical transient candidate
  50. GRB 090726: Swift/UVOT Finding Chart Observation
  51. GRB 090715B - Liverpool Telescope Optical Afterglow Candidate
  52. GRB 090709A: deep optical observation with the 10.4m GTC
  53. GRB 090709: Swift detection of a bright burst
  54. GRB 090705: Swift detection of a possible burst
  55. GRB 090628: Swift XRT refined analysis
  56. GRB 090628: Swift/UVOT Finding Chart Observation
  57. GRB 090621B: Gemini spectrum of afterglow candidate
  58. GRB 090621B: P60 Observations
  59. GRB 090621B: Swift detection of a short hard burst
  60. GRB 090621: Swift detection of a burst
  61. GRB 090618: Swift detection of a bright burst with optical afterglow
  62. GRB 090530: RTT150 Optical Observation
  63. GRB 090529A: RTT150 Optical Observations
  64. Initial Swift/UVOT observations of GRB 090531B
  65. GRB 090531B: Swift-XRT candidate afterglow position
  66. Strong radio emission from SN 2007bg one year after the explosion - detection of spreading, off-axis GRB jet?
  67. GRB 090530A: ROTSE-III Detection of Optical Counterpart
  68. GRB 090530: Swift detection of a burst with an optical counterpart
  69. GRB 090529: Swift detection of a burst
  70. GRB 090519: Swift/UVOT Upper Limits
  71. GRB 090519: NOT afterglow candidate
  72. GRB 090519: Swift detection of a burst
  73. GRB 090518: Swift detection of a burst
  74. GRB 090516: Swift detection of a burst
  75. GRB 090515: MMT/MMIRS NIR Upper Limit
  76. GRB 090509 - Zadko Telescope observations
  77. GRB 090515: Gemini-N upper limit
  78. GRB 090515: Super-LOTIS Upper Limits
  79. GRB 090515: Swift detection of a short burst
  80. GRB 090510: Swift/UVOT host galaxy candidates
  81. GRB 090510: NOT afterglow confirmation
  82. GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
  83. GRB 090510: Swift detection of a short hard burst
  84. GRB 090509: GROND afterglow candidate
  85. GRB090429B: Gemini-N infrared IR candidate
  86. GRB 090429B: Swift detection of a burst
  87. GRB 090429: Swift detection of a burst
  88. GRB 090423: pseudo burst at z=1 and its relation to GRB 080913
  89. GRB 090426: Swift detection of a burst with an optical counterpart
  90. GRB 090423: Swift/BAT spectral lag results
  91. GRB 090424: ROTSE-III Confimation of Optical Counterpart
  92. GRB 090424: Swift detection of a burst with an optical counterpart
  93. GRB 090423 limiting magnitudes
  94. GRB 090423: Near infrared observation at Okayama Observatory
  95. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  96. GRB 090423: NOT z-band limit
  97. GRB090418A Rc-band photometry
  98. GRB090423 - Swift/UVOT upper limits.
  99. GRB 090422: Swift/UVOT Upper Limits
  100. GRB 090423: P60 Observations

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