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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"

7293 results found.

  1. GRB 060515: Swift/XRT Team refined analysis
  2. GRB 060515: Super-LOTIS Observations
  3. GRB060515: Swift/UVOT initial observation
  4. GRB 060515: TAROT optical observation
  5. GRB 060512: 1.54m Kuiper Observations
  6. GRB 060505 - OT candidate + galaxy spectrum
  7. GRB 060512: Swift detection of a burst with an optical afterglow
  8. GRB060510B : Faulkes North Telescope detection
  9. GRB 060510b: Gemini NIR observations
  10. GRB 060510b: NIR observations
  11. GRB 060510B: MDM Observations and candidate OT
  12. GRB 060510B: Swift detection of a burst
  13. GRB060502B: improvement in the XRT afterglow position
  14. GRB 060507: Swift/UVOT Upper Limits
  15. GRB 060507: MDM Optical Upper Limit
  16. GRB 060505: Swift XRT Team Refined Analysis
  17. GRB060425: new MASTER survey method
  18. GRB 060502B MDM Follow-up Observation
  19. GRB060502B: correction to XRT position
  20. GRB 060501: P60 Observations and Candidate Retraction
  21. GRB 060502B: MASTER optical observations
  22. GRB 060502: P60 Afterglow Confirmation
  23. GRB 060501: MDM Observations
  24. GRB060501: Super-LOTIS observations
  25. GRB060501: P60 imaging and afterglow candidate
  26. GRB060428B: possible detection of an optical counterpart by Swift/UVOT.
  27. GRB060428B: Swift XRT Team refined analysis
  28. GRB 060428B: Xinglong I-band limit
  29. GRB 060428B: KAIT observations
  30. GRB060428A: Swift/UVOT observations.
  31. GRB 060428b : Kiso R-band limit
  32. GRB060427:MASTER optical limit
  33. GRB 060428b: Optical afterglow candidate
  34. GRB 060428B: Swift detection of a burst
  35. GRB 060427: NIR observations
  36. GRB 060428: Swift detection of a burst
  37. GRB 060427: Swift/UVOT upper limits.
  38. GRB060425:MASTER survey observations
  39. GRB 060427: Swift detection of a burst
  40. OT 060420: Likely Not a New Cosmic Transient
  41. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  42. GRB060421: Swift/UVOT observations
  43. GRB(?)060421:MASTER optical limit
  44. GRB(?) 060421: Swift detection of a burst
  45. GRB 060418, SMARTS optical/IR afterglow observations
  46. GRB060418 : LT optical afterglow observation
  47. GRB 060418: REM candidate afterglow
  48. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  49. GRB060413: Swift/UVOT upper limits
  50. SGR 1900+14: Swift detection of an outburst
  51. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  52. GRB 060403: Swift detection of a burst
  53. H4043, an unusual high-energy transient observed by HETE
  54. GRB 060322: Confirmation of Swift XRT afterglow
  55. GRB060323: NOT optical observations
  56. GRB 060322: Swift XRT afterglow candidate
  57. GRB 060323: optical afterglow confirmed
  58. GRB 060323: Optical Observations
  59. GRB 060323: Tautenburg OT candidate retraction
  60. GRB 060323: optical observations at TNG
  61. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  62. GRB 060323: Swift/XRT position
  63. GRB 060319: WHT K-band candidate afterglow
  64. GRB060319 : Liverpool Telescope optical limit
  65. GRB060319: MASTER optical observation
  66. GRB 060319: Swift detection of a burst
  67. GRB 060313: early afterglow NIR upper limits with REM
  68. GRB060313: SSO 40inch Observations
  69. GRB 060313: PROMPT Observations
  70. GRB060313:Gemini South Observations
  71. GRB060313: optical observations of the afterglow candidate
  72. GRB 060313: Swift-BAT detection of a bright short hard burst
  73. GRB060312: Swift UVOT observation
  74. GRB 060306: Swift detection of a bright burst
  75. GRB 060223B: Swift XRT possible afterglow
  76. GRB 060223: Swift detection of a burst
  77. GRB060218: Radio Afterglow Discovery
  78. GRB 060219: Swift-BAT detection of a weak burst
  79. Brightening of the Optical Counterpart of the Possible GRB 060218
  80. GRB 060218: MDM Observations
  81. GRB 060218: Pre-burst detection of a possible host galaxy
  82. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  83. GRB 060218: Swift-BAT detection of a possible burst
  84. GRB 060213: optical afterglow not confirmed
  85. Swift UVOT observations of GRB060213
  86. GRB 060213: optical afterglow candidate
  87. GRB060213: Swift XRT observations and possible afterglow candidate
  88. GRB060213: MASTER final result
  89. GRB060213:_MASTER_optical_observation
  90. GRB 050826: Optical Afterglow and Host Galaxy
  91. GRB 060210: Optical Observations
  92. GRB060211.7: MASTER_optical_observation under the snow
  93. GRB 060211B: Swift-BAT detection of a burst
  94. GRB 060211: Swift detection of a long burst
  95. GRB060210:Faulkes Telescope North Afterglow Confirmation
  96. GRB 060210: candidate afterglow
  97. GRB 060210: Swift detection of a burst
  98. GRB060209A: MASTER optical observation
  99. GRB 060209(?): Swift-BAT detection of a possible burst
  100. GRB 060203: Swift/UVOT upper limits

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