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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. GRB060605: Spectral Observations and Redshift
  2. GRB 060605: Swift detection of a burst with optical counterpart
  3. GRB060604: Swift/UVOT detections
  4. GRB 060604: redshift
  5. GRB 060604: Swift detection of a burst with possible optical counterpart
  6. GRB 060602B: Swift detection of a burst
  7. GRB060602B: Watcher observations - no OT candidate
  8. GRB060602B: BOOTES-IR candidate afterglow
  9. GRB 060526: Refined analysis of the Swift-BAT burst
  10. GRB 060526: Swift/XRT Team refined analysis
  11. GRB 060526: Continued emission for the Swift burst
  12. GRB 060526: Swift detection of a burst with x-ray and optical afterglow
  13. GRB 060522: Swift-BAT Refined Analysis
  14. GRB 060522: REM NIR observations
  15. GRB 060522: TNG optical observations
  16. GRB 060515: Swift/XRT Team refined analysis
  17. GRB 060515: Super-LOTIS Observations
  18. GRB060515: Swift/UVOT initial observation
  19. GRB 060515: TAROT optical observation
  20. GRB 060512: 1.54m Kuiper Observations
  21. GRB 060505 - OT candidate + galaxy spectrum
  22. GRB 060512: Swift detection of a burst with an optical afterglow
  23. GRB060510B : Faulkes North Telescope detection
  24. GRB 060510b: Gemini NIR observations
  25. GRB 060510b: NIR observations
  26. GRB 060510B: MDM Observations and candidate OT
  27. GRB 060510B: Swift detection of a burst
  28. GRB060502B: improvement in the XRT afterglow position
  29. GRB 060507: Swift/UVOT Upper Limits
  30. GRB 060507: MDM Optical Upper Limit
  31. GRB 060505: Swift XRT Team Refined Analysis
  32. GRB060425: new MASTER survey method
  33. GRB 060502B MDM Follow-up Observation
  34. GRB060502B: correction to XRT position
  35. GRB 060501: P60 Observations and Candidate Retraction
  36. GRB 060502B: MASTER optical observations
  37. GRB 060502: P60 Afterglow Confirmation
  38. GRB 060501: MDM Observations
  39. GRB060501: Super-LOTIS observations
  40. GRB060501: P60 imaging and afterglow candidate
  41. GRB060428B: possible detection of an optical counterpart by Swift/UVOT.
  42. GRB060428B: Swift XRT Team refined analysis
  43. GRB 060428B: Xinglong I-band limit
  44. GRB 060428B: KAIT observations
  45. GRB060428A: Swift/UVOT observations.
  46. GRB 060428b : Kiso R-band limit
  47. GRB060427:MASTER optical limit
  48. GRB 060428b: Optical afterglow candidate
  49. GRB 060428B: Swift detection of a burst
  50. GRB 060427: NIR observations
  51. GRB 060428: Swift detection of a burst
  52. GRB 060427: Swift/UVOT upper limits.
  53. GRB060425:MASTER survey observations
  54. GRB 060427: Swift detection of a burst
  55. OT 060420: Likely Not a New Cosmic Transient
  56. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  57. GRB060421: Swift/UVOT observations
  58. GRB(?)060421:MASTER optical limit
  59. GRB(?) 060421: Swift detection of a burst
  60. GRB 060418, SMARTS optical/IR afterglow observations
  61. GRB060418 : LT optical afterglow observation
  62. GRB 060418: REM candidate afterglow
  63. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  64. GRB060413: Swift/UVOT upper limits
  65. SGR 1900+14: Swift detection of an outburst
  66. GRB 060413: Refined analysis of the Swift-BAT burst
  67. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  68. GRB 060403: Refined analysis of the Swift-BAT burst
  69. GRB 060403: Swift detection of a burst
  70. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  71. GRB 060322: Confirmation of Swift XRT afterglow
  72. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  73. GRB060323: NOT optical observations
  74. GRB 060322: Swift XRT afterglow candidate
  75. GRB 060323: optical afterglow confirmed
  76. GRB 060323: Optical Observations
  77. GRB 060323: Tautenburg OT candidate retraction
  78. GRB 060323: optical observations at TNG
  79. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  80. GRB 060323: Swift/XRT position
  81. GRB 060322: Swift-BAT detection of a 200-sec burst
  82. GRB 060319: WHT K-band candidate afterglow
  83. GRB060319 : Liverpool Telescope optical limit
  84. GRB060319: MASTER optical observation
  85. GRB 060319: Swift detection of a burst
  86. GRB 060313: early afterglow NIR upper limits with REM
  87. GRB060313: SSO 40inch Observations
  88. GRB 060313: PROMPT Observations
  89. GRB060313:Gemini South Observations
  90. GRB060313: optical observations of the afterglow candidate
  91. GRB 060313: Swift-BAT detection of a bright short hard burst
  92. GRB060312: Swift UVOT observation
  93. GRB 060306: Swift-BAT refined analysis
  94. GRB 060306: Swift detection of a bright burst
  95. GRB 060223B: Swift XRT possible afterglow
  96. GRB 060218/SN 2006aj: ABT observations
  97. GRB 060218: rebrightening
  98. GRB 060223: Swift detection of a burst
  99. GRB 060218: spectroscopic observations
  100. GRB 060218: Likely an underluminous GRB

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