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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"

2900 results found.

  1. GRB 071010B: Photometry after 1.6 days
  2. GRB 071010A: Continued Keck Imaging
  3. GRB 071006, Swift-BAT refined analysis
  4. GRB 071010B: Swift detection of a burst
  5. Recent SGR1806-20 Activity
  6. GRB 070917: Swift detection of a bright burst
  7. GRB 070808, Swift-BAT refined analysis
  8. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  9. GRB 070729, Swift-BAT refined analysis
  10. GRB 070724B: Swift-XRT afterglow likely candidate
  11. GRB 070721A : Faulkes Telescope South optical limit
  12. GRB 070721A, Swift-BAT refined analysis
  13. GRB 070621: Watcher Observations
  14. GRB070520B: optical observations
  15. GRB 070521, optical observation
  16. GRB 070521, Swift-BAT refined analysis
  17. GRB 070521: optical limit by Pi of the Sky
  18. GRB 070419A: RAPTOR Detection of Early Emission
  19. GRB070330: Correction to UVOT position
  20. UVOT observations of GRB070330
  21. GRB 070330, Swift-BAT refined analysis
  22. GRB 070330: Swift-XRT refined analysis
  23. GRB 070330: Swift detection of a burst
  24. GRB 070311: MDM Optical Detection
  25. GRB070227: Swift-XRT refined analysis
  26. VLA observation of GRB 070224
  27. GRB 070227: optical observations
  28. GRB 070227: optical observations
  29. GRB 070209: Swift XRT analysis
  30. GRB 070103: Swift detection of a burst
  31. Retractions of previous Swift-BAT triggers
  32. GRB 061201: Magellan Redshift of nearby Abell cluster
  33. GRB061202 optical limit by "Pi of the Sky"
  34. RHESSI Spectrum of GRB061126
  35. GRB 061126: SARA Observations
  36. GRB 061126: Swift detection of a burst
  37. GRB061122: Swift/UVOT Optical Observations
  38. GRB 061110: Swift detection of a burst
  39. GRB061019: second epoch CrAO observations
  40. GRB 061028: MDM Observations
  41. GRB 061028, Swift-BAT refined analysis
  42. GRB061019: optical observations
  43. GRB 061007: Second Epoch ATCA Radio Observations
  44. GRB 061007: ATCA Radio Observations
  45. GRB060912: Swift/UVOT Observations
  46. GRB060904b optical detections (delayed report due to internet outage)
  47. GRB 060904B: RTT150 optical observations
  48. Two bright bursts from SGR 1806-20 detected with IBAS
  49. GRB 060825: VLA observations
  50. GRB 060825: XRT Team Refined Analysis
  51. GRB 060825: Swift-BAT Refined Analysis
  52. GRB060825: BOOTES-IR optical observations
  53. Konus-Wind observation of GRB 060813
  54. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  55. GRB 060805: Swift detection of a burst
  56. GRB 060801, optical observation
  57. GRB 060605: SkyNet Optical Limits
  58. GRB 060712: Swift detection of a burst
  59. GRB 060502B: A Bright Early-type Galaxy as Putative Host of the Short Burst
  60. GRB 060607: REM NIR afterglow
  61. GRB 060522: Swift detection of a burst with possible optical afterglow
  62. GRB 060516: Swift detection of a burst
  63. GRB060501: P60 imaging and afterglow candidate
  64. GRB060428B, optical observation
  65. GRB060424: optical afterglow detection
  66. GRB 060424: Refined analysis of the Swift-BAT burst
  67. GRB 060403: Swift detection of a burst
  68. GRB 060312: ROTSE-III Optical Limits
  69. Bright short hard GRB 060303: IPN localization and Konus spectrum
  70. GRB 060223B: Swift XRT possible afterglow
  71. GRB 060218/SN 2006aj: RBO optical observations
  72. GRB 060223B: ART optical limits
  73. GRB 060206: Swift/UVOT Observations
  74. GRB 060209(?): Swift-BAT detection of a possible burst
  75. GRB060206: Swift-BAT detection of a burst
  76. GRB060124: detailed XRT analysis
  77. GRB 060123: Swift detection of a very long, faint burst
  78. GRB 060117: PROMPT Observations
  79. GRB 060116: PROMPT Observations
  80. GRB 060105: Radio observations
  81. GRB 060102 - no XRT afterglow
  82. GRB 051210: Swift/UVOT upper limits
  83. GRB051210: Swift UVOT Observation
  84. GRB 051210: Swift detection of a burst
  85. GRB051111: Swift/UVOT Observations
  86. GRB 051111: Swift-BAT refined analysis
  87. GRB051103: MASTER: OT limit and host galaxy candidates
  88. GRB051028: Swift-XRT refined analysis
  89. GRB051105A: Swift/UVOT Observations
  90. GRB051103:_MASTER_optical_observations
  91. GRB051028: WHT optical candidate
  92. GRB051028: Swift XRT Position
  93. SGR 1806-20: continued moderate activity seen with INTEGRAL
  94. GRB051012: Swift-XRT analysis
  95. GRB 051021B: Refined analysis of the Swift-BAT burst
  96. GRB 051021: SOAR NIR Observations
  97. Swift-BAT triggered on a posible CR Shower or possible GRB
  98. GRB 051012: Swift-BAT detection of burst yesterday
  99. GRB 050922B: optical limit
  100. GRB 050906: Possible X-ray Counterpart

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