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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"

2795 results found.

  1. GRB 070917: Swift detection of a bright burst
  2. GRB 070808, Swift-BAT refined analysis
  3. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  4. GRB 070729, Swift-BAT refined analysis
  5. GRB 070724B: Swift-XRT afterglow likely candidate
  6. GRB 070721A : Faulkes Telescope South optical limit
  7. GRB 070721A, Swift-BAT refined analysis
  8. GRB 070621: Watcher Observations
  9. GRB070520B: optical observations
  10. GRB 070521, optical observation
  11. GRB 070521, Swift-BAT refined analysis
  12. GRB 070521: optical limit by Pi of the Sky
  13. GRB 070419A: RAPTOR Detection of Early Emission
  14. GRB070330: Correction to UVOT position
  15. UVOT observations of GRB070330
  16. GRB 070330, Swift-BAT refined analysis
  17. GRB 070330: Swift-XRT refined analysis
  18. GRB 070330: Swift detection of a burst
  19. GRB 070311: MDM Optical Detection
  20. GRB070227: Swift-XRT refined analysis
  21. VLA observation of GRB 070224
  22. GRB 070227: optical observations
  23. GRB 070227: optical observations
  24. GRB 070209: Swift XRT analysis
  25. GRB 070103: Swift detection of a burst
  26. Retractions of previous Swift-BAT triggers
  27. GRB 061201: Magellan Redshift of nearby Abell cluster
  28. GRB061202 optical limit by "Pi of the Sky"
  29. RHESSI Spectrum of GRB061126
  30. GRB 061126: SARA Observations
  31. GRB 061126: Swift detection of a burst
  32. GRB061122: Swift/UVOT Optical Observations
  33. GRB 061110: Swift detection of a burst
  34. GRB061019: second epoch CrAO observations
  35. GRB 061028: MDM Observations
  36. GRB 061028, Swift-BAT refined analysis
  37. GRB061019: optical observations
  38. GRB 061007: Second Epoch ATCA Radio Observations
  39. GRB 061007: ATCA Radio Observations
  40. GRB060912: Swift/UVOT Observations
  41. GRB060904b optical detections (delayed report due to internet outage)
  42. GRB 060904B: RTT150 optical observations
  43. Two bright bursts from SGR 1806-20 detected with IBAS
  44. GRB 060825: VLA observations
  45. GRB 060825: XRT Team Refined Analysis
  46. GRB 060825: Swift-BAT Refined Analysis
  47. GRB060825: BOOTES-IR optical observations
  48. Konus-Wind observation of GRB 060813
  49. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  50. GRB 060805: Swift detection of a burst
  51. GRB 060801, optical observation
  52. GRB 060605: SkyNet Optical Limits
  53. GRB 060712: Swift detection of a burst
  54. GRB 060502B: A Bright Early-type Galaxy as Putative Host of the Short Burst
  55. GRB 060607: REM NIR afterglow
  56. GRB 060522: Swift detection of a burst with possible optical afterglow
  57. GRB 060516: Swift detection of a burst
  58. GRB060501: P60 imaging and afterglow candidate
  59. GRB060428B, optical observation
  60. GRB060424: optical afterglow detection
  61. GRB 060424: Refined analysis of the Swift-BAT burst
  62. GRB 060403: Swift detection of a burst
  63. GRB 060312: ROTSE-III Optical Limits
  64. Bright short hard GRB 060303: IPN localization and Konus spectrum
  65. GRB 060223B: Swift XRT possible afterglow
  66. GRB 060218/SN 2006aj: RBO optical observations
  67. GRB 060223B: ART optical limits
  68. GRB 060206: Swift/UVOT Observations
  69. GRB 060209(?): Swift-BAT detection of a possible burst
  70. GRB060206: Swift-BAT detection of a burst
  71. GRB060124: detailed XRT analysis
  72. GRB 060123: Swift detection of a very long, faint burst
  73. GRB 060117: PROMPT Observations
  74. GRB 060116: PROMPT Observations
  75. GRB 060105: Radio observations
  76. GRB 060102 - no XRT afterglow
  77. GRB 051210: Swift/UVOT upper limits
  78. GRB051210: Swift UVOT Observation
  79. GRB 051210: Swift detection of a burst
  80. GRB051111: Swift/UVOT Observations
  81. GRB 051111: Swift-BAT refined analysis
  82. GRB051103: MASTER: OT limit and host galaxy candidates
  83. GRB051028: Swift-XRT refined analysis
  84. GRB051105A: Swift/UVOT Observations
  85. GRB051103:_MASTER_optical_observations
  86. GRB051028: WHT optical candidate
  87. GRB051028: Swift XRT Position
  88. SGR 1806-20: continued moderate activity seen with INTEGRAL
  89. GRB051012: Swift-XRT analysis
  90. GRB 051021B: Refined analysis of the Swift-BAT burst
  91. GRB 051021: SOAR NIR Observations
  92. Swift-BAT triggered on a posible CR Shower or possible GRB
  93. GRB 051012: Swift-BAT detection of burst yesterday
  94. GRB 050922B: optical limit
  95. GRB 050906: Possible X-ray Counterpart
  96. GRB 050906: MARGE Optical Limits
  97. GRB 050824: MDM Observations
  98. GRB050824: First 2 hours of power low optical decay?
  99. GRB050824: MASTER final analysis of the OT observations
  100. GRB050822: Swift/UVOT upper limits

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