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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"

3400 results found.

  1. Recent SGR1806-20 Activity
  2. GRB 070920B, Swift-BAT refined analysis
  3. GRB 070920: TAROT Calern observatory optical observations
  4. GRB 070911: Swift detection of a burst
  5. GRB070805 XRT and UVOT afterglow candidate
  6. GRB 070805, Swift-BAT refined analysis
  7. GRB 070724B: Swift-XRT afterglow confirmation
  8. GRB 070724B: Swift-XRT afterglow likely candidate
  9. GRB 070724B: Swift-XRT afterglow candidates
  10. Swift XRT observation of GRB 070707
  11. GRB 070704: Swift detection of a burst
  12. GRB 070628: NIR detection of afterglow
  13. OT20050728 was not an optical GRB afterglow
  14. GRB 070621: Gemini South optical imaging
  15. GRB 070616: BTA optical observations
  16. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  17. GRB 070610: Watcher Observations
  18. GRB 070611: ROTSE-III Optical Limits
  19. GRB 070611: Swift detection of a burst
  20. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  21. GRB 070521, Swift-BAT refined analysis
  22. GRB 070521: optical limit by Pi of the Sky
  23. GRB 070518: Swift-XRT refined analysis
  24. GRB 070512: IPN localization and Konus spectrum of a bright burst
  25. GRB 070509: ROTSE-III Optical Limits
  26. GRB 070508, Swift-BAT refined analysis
  27. GRB 070427: Swift detection of a burst
  28. GRB 070420 Swift-BAT Refined Analysis
  29. GRB 070419A: MARGE Observations
  30. GRB 070411: Swift detection of a burst with optical afterglow
  31. GRB 070330, Swift-BAT refined analysis
  32. GRB 070330 - Watcher Observations
  33. Short-Hard GRB 070209: PROMPT Observations
  34. GRB 070318, Swift-BAT refined analysis
  35. GRB 070318: Swift detection of a burst with an optical afterglow
  36. GRB 070306: IR observations and candidate afterglow
  37. GRB 070306: Optical and IR observations with KANATA
  38. VLA observation of GRB 070223
  39. Konus-Wind and Konus-A observations of GRB 070220
  40. GRB 070220: MITSuME Okayama Optical Observation
  41. GRB070208 - SDSS Pre-Burst Observations
  42. GRB 070208: Early IR detection and afterglow astrometry
  43. GRB070208: Faulkes Telescope North Afterglow Identification
  44. GRB 070208: Swift detection of a burst
  45. GRB070129: MITSuME optical observation
  46. GRB 070129: Swift detection of a burst
  47. Swift-BAT trigger 257213 is a Galactic Center transient
  48. Trigger 255685: Swift detection of a possible burst
  49. GRB 070110: Swift detection of a burst with a possible optical afterglow
  50. Retractions of previous Swift-BAT triggers
  51. GRB 061217, Swift-BAT refined analysis
  52. GRB 061213: MASTER-VWF-Kislovodsk optical candidate
  53. GRB 060926: MASTER: discovery of the optical flare
  54. GRB 061126: Early Detection of the IR Afterglow
  55. GRB 061121: MDM Optical Decay
  56. GRB 061121: MDM Optical Observations
  57. GRB 061121: Swift detection of a bright burst with an optical counterpart
  58. GRB 061007: Third Epoch ATCA Radio Observations
  59. GRB 061021: Swift-XRT refined analysis
  60. GRB 061021: Swift/UVOT Observation
  61. GRB 061021, Swift-BAT refined analysis
  62. GRB 061021: Swift detection of a burst
  63. Konus-Wind observation of GRB 060928
  64. GRB 060929: MASTER-VWF-Kislovodsk observations
  65. GRB 060927, Swift-BAT refined analysis
  66. GRB 060926: MASTER: first minutes decay
  67. GRB 060926: Swift-UVOT Detections
  68. GRB 060926: MASTER OT alert observation
  69. GRB 060926: MASTER optical observation
  70. GRB 060926: Swift detection of a burst
  71. GRB 060923C, Swift-BAT partial refined analysis
  72. GRB 060923: KAIT observations
  73. GRB060912: Swift/UVOT Observations
  74. GRB 060912: Correction to GCN 5559
  75. GRB 060912: Swift detection of a burst with an optical afterglow
  76. GRB 060908: Swift detection of a burst with a bright optical counterpart
  77. GRB 060904A: Suzaku-XIS and -HXD observation plan
  78. GRB 060904A: P60 Observations
  79. GRB060904 - SDSS Pre-Burst Observations
  80. GRB 060904: Swift detection of a bright burst
  81. Two bright bursts from SGR 1806-20 detected with IBAS
  82. GRB 060825: Swift-BAT Refined Analysis
  83. GRB 060825: Swift detection of a burst
  84. Konus-Wind observation of GRB 060814
  85. GRB 060813: Refined analysis of the Swift-BAT burst
  86. IPN triangulation of GRB060805B
  87. GRB 060728: Upper limits of the X-ray emission
  88. GRB 060522: VLA observation
  89. GRB 060717: Swift XRT refined position
  90. GRB 060717: Swift detection of a burst
  91. Swift trigger 219136 is probably not a GRB
  92. GRB 060707: Refined analysis of the Swift-BAT burst
  93. GRB 060610: KAIT observations
  94. GRB 060522: PROMPT Optical Limits
  95. GRB 060505: X-ray afterglow - Correction -
  96. GRB 060505: X-ray afterglow
  97. GRB 060510: Swift detection of a burst with optical transient
  98. GRB 060507: MDM Optical Upper Limit
  99. GRB060425: new MASTER survey method
  100. GRB 060505: Swift XRT afterglow canditate position

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