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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"

35981 results found.

  1. GRB 050129: a weak long GRB detected with INTEGRAL
  2. GRB050128: Faulkes Telescope South observations
  3. GRB 050124: Radio Observations
  4. GRB 050128: near-infrared observations with REM
  5. GRB050128,optical observations
  6. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  7. GRB 050126: Radio Observations
  8. GRB050128 Swift-BAT observations
  9. GRB 050128: Swift XRT prompt afterglow position
  10. GRB 050124: K-band afterglow observations
  11. GRB050126: MASTER optical limit for KECK OT
  12. GRB050126: MASTER optical observations
  13. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  14. GRB 050126: Prompt XRT detection and localization
  15. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  16. GRB 050124, SMARTS optical/IR observations
  17. GRB 050117a: Radio Observations
  18. GRB 050124 I-band observation
  19. GRB 050124: NIR Candidates from Keck/NIRC
  20. GRB050124,optical observation
  21. GRB 050124 : Lulin R-band follow-up observation
  22. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  23. GRB 050123 : I-band follow-up observation
  24. GRB050123: optical limit 1.8h before GRB
  25. GRB050123,optical observation
  26. GRB 050123: KAIT observations
  27. GRB050123: P60 Observations
  28. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  29. CFHTLS optical transient unlikely to be a GRB
  30. Unusual optical transient (GRB ???)
  31. GRB050117a: Radio Observations
  32. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  33. GRB 050117, I-band observations
  34. GRB 050117: Optical observation
  35. GRB050117: Refined XRT position
  36. GRB050117: MASTER optical observations
  37. MASTER:GRB050117 SWIFT
  38. GRB050117: Swift-BAT detection of a long multi-peaked burst
  39. Triangulation of Short Hard GRB050112 (large error box)
  40. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  41. SGR 1806-20 and extragalactic short-duration GRBs
  42. SGR 1806-20: Temporal and Spectral behavior of radio transient
  43. SGR 1806-20, RHESSI observations of the 041227 giant flare
  44. SGR1806: Detection of a Sudden Ionospheric Disturbance
  45. GRB 041217: Optical observations
  46. GRB041219, early time observations
  47. IPN localization of giant flare from SGR1806-20
  48. GRB041219; RXTE ASM Observations
  49. NIR Observations of GRB 041219
  50. GRB041223: decay of the afterglow
  51. GRB 041224: near-infrared observations with REM
  52. GRB 041223: XRT afterglow spectrum and light curve
  53. GRB 041223 Fluence measured by Swift-BAT
  54. GRB041223: optical and NIR observations with REM
  55. GRB 041219: TAROT optical observations
  56. GRB 041218: TAROT optical observations
  57. GRB 041223: J-band observations of the afterglow
  58. GRB 041223: Detection of Optical Transient with LCO40
  59. GRB 041219c: PROMPT Observations
  60. GRB 041218: optical observations
  61. GRB 041219: Second Epoch WSRT Radio Observations
  62. GRB 041219: WSRT Radio Afterglow Detection
  63. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  64. GRB 041218: Optical observations
  65. GRB 041219 : optical follow-up observations
  66. Deep RAPTOR observations during GRB 041219
  67. GRB 041218 Optical Observations
  68. GRB 041219 Optical Observations
  69. GRB041219c: Third Burst in One Day from Swift-BAT
  70. GRB041219: Optical Afterglow Detection
  71. GRB041219: Continued NIR Observations
  72. GRB 041219 ,optical observation
  73. GRB 041219: Radio Afterglow Detection
  74. GRB 041218 : Radio Observations
  75. GRB 041218: R-band optical observations
  76. GRB041219: Confirmed NIR Afterglow
  77. GRB041218: Continued P60 Optical Observations
  78. GRB 041218: Optical Observation
  79. GRB 041219: Infrared Afterglow Candidate
  80. GRB041219, BVRcIc field calibration
  81. GRB 041219: Infrared Afterglow Candidate
  82. GRB041218, BVRcIc field calibration
  83. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  84. GRB041219: P60 Optical Observations
  85. GRB 041219 - A long GRB detected by INTEGRAL
  86. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  87. GRB 041217: PROMPT Observations
  88. GRB041218: optical observations
  89. GRB041217: optical limit 30 min after GRB
  90. GRB 041218; optical candidate
  91. GRB 041218: Optical observations
  92. GRB 041217: LCO40 Optical Observations and Possible Candidates
  93. GRB 041218 - A long GRB detected by integral
  94. GRB041217: Optical Observations
  95. GRB041217: P60 Optical Observations
  96. GRB041217: Infrared Observations
  97. GRB041217: The First GRB Located On-Board Swift
  98. GRB041211: Faulkes Telescope continued optical monitoring
  99. Optical Transient in Lynx not a GRB
  100. Optical transient (GRB?) in Lynx

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