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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"

28066 results found.

  1. GRB 100103A: Swift/XRT position
  2. Swift Trigger 381591 is probably not a burst
  3. GRB 091231: GROND NIR observations
  4. Swift Trigger 381591: Uncatalogued UVOT Source
  5. GRB 091230: Swift/UVOT Observations
  6. Trigger 381591: Swift detection of a possible burst
  7. GRB 091230: Swift-XRT observation
  8. GRB 091230: GROND optical/NIR afterglow candidate
  9. Swift Trigger 381434 is not a GRB
  10. Trigger 381434: Swift detection of a possible burst
  11. GRB 091221 : IRSF NIR upper limit
  12. GRB 091221: Skynet/PROMPT Detections
  13. GRB 091117: Swift-XRT late time observations
  14. GRB 091221: Swift/UVOT refined analysis
  15. GRB 091221: Swift-XRT refined analysis
  16. GRB 091221: Enhanced Swift-XRT position
  17. GRB 091221, GROND observations
  18. GRB 091221: UVOT Confirmation of an Optical Afterglow
  19. GRB 091221: ROTSE-III Detection of Optical Counterpart
  20. GRB 091221: Swift detection of a burst
  21. Swift trigger 379449 (possible GRB) is not a burst
  22. GRB 091215: Faulkes Telescope North observations
  23. Trigger 379449: Swift detection of a possible burst
  24. GRB 091208B: Xinglong TNT optical observation
  25. GRB 091208B: optical observations
  26. GRB 091208B: Keck HIRES redshift confirmation
  27. GRB 091208B: GROND observations
  28. GRB 091208A: Swift-XRT observations
  29. GRB091208B: NOT optical observations
  30. GRB 091208B: Swift-XRT refined analysis
  31. GRB091208B: Swift/UVOT refined analysis
  32. GRB 091208B: Gemini-North redshift
  33. GRB 091208B: Faulkes Telescope North and South Optical Afterglow
  34. GRB 091208B: MITSuME Akeno Optical Observation
  35. GRB 091208B: Enhanced Swift-XRT position
  36. GRB 091208B: MITSuME Okayama Optical Observation
  37. GRB 091208B: Swift detection of a burst with an optical afterglow
  38. GRB 091208B: BOOTES-3 optical afterglow
  39. GRB 091208: Swift detection of a burst
  40. GRB 091127: Skynet/PROMPT Observations of Possible Host Galaxy
  41. GRB 091202: GTC & CAHA optical/nIR afterglow candidate
  42. GRB 091109A: GROND confirmation of redshift z = 3.5
  43. GRB091127: Continuing Swift/UVOT Observations
  44. GRB 091127, SMARTS optical/IR afterglow observations
  45. GRB091202: Swift-XRT refined analysis
  46. GRB 091202: Swift/UVOT Upper Limits
  47. GRB 091202: Liverpool Telescope observations
  48. GRB 091202: Optical and NIR observations
  49. GRB 091202 - UVOT-enhanced XRT position
  50. GRB 091127: redshift confirmation with X-shooter
  51. GRB 091117: Chandra Observations
  52. GRB 091127: Skynet/PROMPT Continued Observations of Fading
  53. Short X-ray Transient Detection by MAXI/GSC
  54. GRB 091130A: Xinglong TNT upper limit
  55. GRB 091123: Fermi GBM detection of a very long burst
  56. GRB 091126B: Fermi GBM detection
  57. GRB 091126: Fermi GBM detection
  58. GRB 091130B: Swift-XRT team refined analysis
  59. GRB 091130B: Swift/UVOT Upper Limits
  60. GRB 091127: Skynet/PROMPT Observations of Fading
  61. GRB 091130B: Enhanced Swift-XRT position
  62. Swift trigger 377436 (possible GRB 091130A) is not a burst
  63. GRB 091130B: MASTER observations
  64. GRB 091130B: SDSS galaxy at XRT location
  65. GRB 091130B: Swift detection of a burst
  66. GRB 091130: Swift detection of a possible burst
  67. GRB 091127: Radio observations
  68. GRB 091128: Fermi GBM detection
  69. GRB 091127: optical observations
  70. GRB 091127: LABOCA/APEX submm observations
  71. GRB 091127: Further NOT optical observations
  72. GRB 091127: Fermi GBM detection
  73. GRB 091127: Gemini-N redshift
  74. GRB 091127: Swift-XRT afterglow detection and analysis
  75. GRB 091127: Swift/UVOT observations
  76. GRB 091127: CAHA 1.23m I-band observations
  77. GRB 091127: NOT observations
  78. GRB 091127 : GROND observations
  79. GRB 091127: REM NIR afterglow detection
  80. GRB 091127: Swift/UVOT Detection of an Optical Afterglow
  81. GRB 091127: Liverpool Telescope afterglow candidate
  82. GRB 091127: Swift detection of a burst
  83. GRB 091120: MAXI GSC detection
  84. GRB 091117: TNG optical observations
  85. GRB 091117A: Swift/UVOT followup observations
  86. GRB 091117: 2nd epoch of Magellan optical observations
  87. GRB 091117: VLA radio observations
  88. GRB 091117: Swift-XRT observations
  89. GRB 091117: Evidence for Variability of XRT Source #1
  90. GRB091117: Gemini South Observations
  91. GRB 091117: Swift XRT refined analysis
  92. GRB 091117: Gemini-North spectroscopy of DSS galaxy
  93. GRB 091117: Magellan optical observations
  94. GRB 091117: XRT source coincident with a DSS galaxy
  95. GRB091111: Swift XRT refined analysis
  96. GRB 091031: Fermi LAT detection of a faint burst
  97. GRB 091112: Swift detection of a possible burst
  98. GRB 091109A: GROND and VLT observations
  99. GRB 091109B: Swift/UVOT Upper Limits
  100. GRB 091109B: VLT afterglow confirmation

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