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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"

4956 results found.

  1. GRB 060522: PROMPT Optical Limits
  2. GRB 060604: Swift detection of a burst with possible optical counterpart
  3. GRB060602A: optical observations(/transient?)
  4. GRB060602 - SDSS Pre-Burst Observations
  5. GRB060526: Optical counterpart from MIRO
  6. GRB 060526: Optical Flare
  7. GRB 060526: MDM-2.4m Observations
  8. GRB 060510A: Swift/UVOT Detection of an Optical Afterglow
  9. GRB060510A: XRT refined analysis
  10. GRB060510 - SDSS Pre-Burst Observations
  11. GRB 060510B: Swift detection of a burst
  12. GRB 060510: Swift detection of a burst with optical transient
  13. GRB 060502B MDM Follow-up Observation
  14. GRB 060502: Swift detection of a burst with an optical counterpart
  15. GRB 060501: MDM Observations
  16. GRB060501: Super-LOTIS observations
  17. GRB060501: P60 imaging and afterglow candidate
  18. GRB060501: Swift XRT position
  19. GRB 060428B: KAIT observations
  20. GRB060427:MASTER optical limit
  21. GRB 060428B: Swift detection of a burst
  22. GRB 060428: Swift detection of a burst
  23. GRB 060421: TTT Observations
  24. GRB(?) 060421: Swift detection of a burst
  25. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  26. GRB 060413: XRT refined analysis
  27. SGR 1900+14: BAT observations
  28. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  29. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  30. GRB 060322: Confirmation of Swift XRT afterglow
  31. GRB 060322: Swift-BAT detection of a 200-sec burst
  32. GRB060219: optical observation
  33. GRB 060306: Swift detection of a bright burst
  34. GRB 060218/SN 2006aj: WIRO optical observations
  35. GRB 060211B: Skynet Observations
  36. GRB 060213: optical afterglow candidate
  37. GRB060213: Swift XRT observations and possible afterglow candidate
  38. GRB060213: MASTER final result
  39. GRB060213:_MASTER_optical_observation
  40. GRB 060213: IPN localization
  41. GRB060121: optical observations
  42. GRB 060211: ROTSE-III Optical Limits
  43. GRB 060211: Swift detection of a long burst
  44. GRB060210: Swift XRT Refined Analysis
  45. GRB 060210: Swift detection of a burst
  46. Swift-BAT trigger 180931 is not a GRB
  47. GRB060209: RTT150 optical observations
  48. GRB 060209 : TAROT optical observation
  49. GRB060209A: MASTER optical observation
  50. GRB 060206: TTT Observations
  51. GRB 060206: Super-LOTIS observations
  52. GRB060204C: optical observation
  53. GRB060204B, optical observation
  54. GRB 060202: GETS observation
  55. GRB060202, optical observation
  56. GRB 060202: Swift/UVOT upper limits
  57. GRB 060121: Gemini Late-time Observations
  58. GRB 060130, SMARTS optical observations
  59. GRB 060130: FRAM optical observations
  60. GRB060124: detailed XRT analysis
  61. GRB 060116: MARGE optical observations
  62. GRB 060121: candidate optical counterpart
  63. GRB060121 - SDSS pre-burst observations
  64. GRB 060116: IR Candidate Afterglow
  65. GRB 060116: Swift-BAT detection of a burst
  66. GRB 060115: Swift/UVOT upper limits
  67. GRB 060115: Swift detection of a burst
  68. GRB060108: Faulkes North afterglow evidence
  69. GRB 060110: MARGE observations
  70. GRB 060111B: Swift detection of a burst
  71. GRB060110, optical observation
  72. GRB 060109: Swift/UVOT upper limits
  73. GRB060109, optical observation
  74. GRB 060109: Swift Detection of a long burst
  75. GRB060108: SDSS pre-burst observations
  76. GRB 060105: Mitsume optical observations
  77. GRB060105, optical observation
  78. GRB060105 : Kiso optical observation
  79. GRB051211B: optical observations
  80. GRB 051221B: ROTSE-III Optical Limits
  81. Refined analysis of the SWIFT J1626.6-5156
  82. Swift detection of an RS CVn flare star
  83. GRB051105: optical observations
  84. Possible resuming of the SGR 1806-20 activity
  85. GRB051117A : XRT refined analysis
  86. GRB 051117B: Swift detection of a burst
  87. GRB 051109B : Nainital upper limits
  88. GRB 051114: Swift-BAT refined analysis
  89. GRB 051114: Swift-BAT detection of a short burst
  90. GRB 051105a: GETS optical limit
  91. GRB 051109b: GETS observation
  92. GRB 051109A: KAIT optical observations
  93. GRB 051109A: Swift-UVOT Observations
  94. GRB 051109B Kiso optical follow-up observation
  95. GRB 051109a: IR Photometry and Astrometry
  96. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  97. GRB 051109a: IR Detections
  98. GRB051103: MASTER: OT limit and host galaxy candidates
  99. GRB051103:_MASTER_optical_observations
  100. IPN triangulation and Konus spectrum of the bright short/hard GRB051103

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