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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').
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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"

24877 results found.

  1. GRB 050128: Swift XRT prompt afterglow position
  2. GRB050126: MASTER optical limit for KECK OT
  3. GRB050126: Burst Parameters Measured by BAT
  4. GRB050126: MASTER optical observations
  5. GRB 050124 I-band observation
  6. GRB050124,optical observation
  7. GRB 050124 : Lulin R-band follow-up observation
  8. GRB050124: Updated Swift XRT Position and Fluxes
  9. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  10. GRB050124: Refined BAT position, spectral and fluence information
  11. GRB 050123 : I-band follow-up observation
  12. GRB050123,optical observation
  13. GRB 050123: KAIT observations
  14. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  15. GRB050117: Refined XRT position
  16. GRB050117: MASTER optical observations
  17. MASTER:GRB050117 SWIFT
  18. GRB050117: Swift XRT Position
  19. Triangulation of Short Hard GRB050112 (large error box)
  20. SGR 1806-20: Further VLA Observations
  21. SGR1806-20: Swift-BAT observations of two additional bursts
  22. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  23. Further VLA observations of SGR 1806-20
  24. SGR 1806-20 and extragalactic short-duration GRBs
  25. Further ATCA observations of SGR 1806-20
  26. Fourth Epoch VLA observations of SGR 1806-20
  27. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  28. ATCA observations of SGR 1806-20
  29. SGR 1806-20, RHESSI observations of the 041227 giant flare
  30. Third epoch observations of SGR 1806-20 with VLA
  31. Second Epoch VLA observations of SGR 1806-20
  32. Second-epoch VLA observations of SGR 1806-20
  33. SGR1806 VLA Observations
  34. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  35. GRB 041217: Optical observations
  36. GRB041228: Swift-BAT detection of a burst
  37. GRB041219; RXTE ASM Observations
  38. NIR Observations of GRB 041219
  39. GRB041226: Swift-BAT detection of a burst
  40. GRB041223: decay of the afterglow
  41. GRB 041224: near-infrared observations with REM
  42. GRB 041223 Fluence measured by Swift-BAT
  43. GRB041223: optical and NIR observations with REM
  44. Swift-BAT Time History of GRB041219
  45. GRB 041219: TAROT optical observations
  46. GRB 041218: TAROT optical observations
  47. GRB 041223: J-band observations of the afterglow
  48. GRB 041219c: PROMPT Observations
  49. GRB041223: Swift-BAT detection of a bright long burst
  50. GRB 041218: optical observations
  51. GRB 041219 : optical follow-up observations
  52. Deep RAPTOR observations during GRB 041219
  53. GRB 041218 Optical Observations
  54. GRB041219: Continued NIR Observations
  55. GRB 041219 ,optical observation
  56. GRB 041219: Radio Afterglow Detection
  57. GRB 041218 : Radio Observations
  58. GRB 041218: R-band optical observations
  59. GRB041218: optical observations
  60. GRB041219: Confirmed NIR Afterglow
  61. Swift-BAT detection of the bright long burst GRB041219
  62. GRB 041219: Infrared Afterglow Candidate
  63. GRB041219, BVRcIc field calibration
  64. GRB 041219: Infrared Afterglow Candidate
  65. GRB041218, BVRcIc field calibration
  66. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  67. GRB 041219 - A long GRB detected by INTEGRAL
  68. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  69. GRB 041217: PROMPT Observations
  70. GRB 041217: LCO40 Optical Observations and Possible Candidates
  71. GRB 041218 - A long GRB detected by integral
  72. GRB041217: NIR and optical observations with REM
  73. GRB041217: Infrared Observations
  74. GRB041217: The First GRB Located On-Board Swift
  75. GRB041211: Faulkes Telescope continued optical monitoring
  76. Optical Transient in Lynx not a GRB
  77. Optical transient (GRB?) in Lynx
  78. GRB041211: RAPTOR observations
  79. GRB041211: Ashra Prototype optical observation
  80. GRB041211, BVRcIc field calibration
  81. GRB041211,optical observation
  82. GRB 041211: Infrared Observations
  83. GRB 041211: KAIT observations
  84. GRB 041211: Optical follow-up in East Asian region
  85. Triangulation of short GRB 041116 (large error box)
  86. GRB 040924: Afterglow Color
  87. GRB 041006: GETS Optical Afterglow Observation
  88. Summary of the recent bursts from SGR 1806-20
  89. GRB 041006: Optical Observations
  90. GRB041006, late-time optical photometry
  91. GRB041006: RTT150 Optical Observations
  92. HST Observations: XRF 040701 and 040812
  93. Bright bursts from SGR1806-20
  94. GRB 041016: BOOTES-2 simultaneous observation
  95. GRB041006: RTT150 Optical Observations
  96. GRB041016,optical observation
  97. GRB 041016: Optical limits
  98. GRB 041016:Optical limit during first minute
  99. GRB 041015: Optical Observations at Rikubetsu
  100. GRB 041016: Optical limit

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