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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"

24671 results found.

  1. GRB 050124 : Lulin R-band follow-up observation
  2. GRB050124: Updated Swift XRT Position and Fluxes
  3. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  4. GRB050124: Refined BAT position, spectral and fluence information
  5. GRB 050123 : I-band follow-up observation
  6. GRB050123,optical observation
  7. GRB 050123: KAIT observations
  8. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  9. GRB050117: Refined XRT position
  10. GRB050117: MASTER optical observations
  11. MASTER:GRB050117 SWIFT
  12. GRB050117: Swift XRT Position
  13. Triangulation of Short Hard GRB050112 (large error box)
  14. SGR 1806-20: Further VLA Observations
  15. SGR1806-20: Swift-BAT observations of two additional bursts
  16. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  17. Further VLA observations of SGR 1806-20
  18. SGR 1806-20 and extragalactic short-duration GRBs
  19. Further ATCA observations of SGR 1806-20
  20. Fourth Epoch VLA observations of SGR 1806-20
  21. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  22. ATCA observations of SGR 1806-20
  23. SGR 1806-20, RHESSI observations of the 041227 giant flare
  24. Third epoch observations of SGR 1806-20 with VLA
  25. Second Epoch VLA observations of SGR 1806-20
  26. Second-epoch VLA observations of SGR 1806-20
  27. SGR1806 VLA Observations
  28. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  29. GRB 041217: Optical observations
  30. GRB041228: Swift-BAT detection of a burst
  31. GRB041219; RXTE ASM Observations
  32. NIR Observations of GRB 041219
  33. GRB041226: Swift-BAT detection of a burst
  34. GRB041223: decay of the afterglow
  35. GRB 041224: near-infrared observations with REM
  36. GRB 041223 Fluence measured by Swift-BAT
  37. GRB041223: optical and NIR observations with REM
  38. Swift-BAT Time History of GRB041219
  39. GRB 041219: TAROT optical observations
  40. GRB 041218: TAROT optical observations
  41. GRB 041223: J-band observations of the afterglow
  42. GRB 041219c: PROMPT Observations
  43. GRB041223: Swift-BAT detection of a bright long burst
  44. GRB 041218: optical observations
  45. GRB 041219 : optical follow-up observations
  46. Deep RAPTOR observations during GRB 041219
  47. GRB 041218 Optical Observations
  48. GRB041219: Continued NIR Observations
  49. GRB 041219 ,optical observation
  50. GRB 041219: Radio Afterglow Detection
  51. GRB 041218 : Radio Observations
  52. GRB 041218: R-band optical observations
  53. GRB041218: optical observations
  54. GRB041219: Confirmed NIR Afterglow
  55. Swift-BAT detection of the bright long burst GRB041219
  56. GRB 041219: Infrared Afterglow Candidate
  57. GRB041219, BVRcIc field calibration
  58. GRB 041219: Infrared Afterglow Candidate
  59. GRB041218, BVRcIc field calibration
  60. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  61. GRB 041219 - A long GRB detected by INTEGRAL
  62. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  63. GRB 041217: PROMPT Observations
  64. GRB 041217: LCO40 Optical Observations and Possible Candidates
  65. GRB 041218 - A long GRB detected by integral
  66. GRB041217: NIR and optical observations with REM
  67. GRB041217: Infrared Observations
  68. GRB041217: The First GRB Located On-Board Swift
  69. GRB041211: Faulkes Telescope continued optical monitoring
  70. Optical Transient in Lynx not a GRB
  71. Optical transient (GRB?) in Lynx
  72. GRB041211: RAPTOR observations
  73. GRB041211: Ashra Prototype optical observation
  74. GRB041211, BVRcIc field calibration
  75. GRB041211,optical observation
  76. GRB 041211: Infrared Observations
  77. GRB 041211: KAIT observations
  78. GRB 041211: Optical follow-up in East Asian region
  79. Triangulation of short GRB 041116 (large error box)
  80. GRB 040924: Afterglow Color
  81. GRB 041006: GETS Optical Afterglow Observation
  82. Summary of the recent bursts from SGR 1806-20
  83. GRB 041006: Optical Observations
  84. GRB041006, late-time optical photometry
  85. GRB041006: RTT150 Optical Observations
  86. HST Observations: XRF 040701 and 040812
  87. Bright bursts from SGR1806-20
  88. GRB 041016: BOOTES-2 simultaneous observation
  89. GRB041006: RTT150 Optical Observations
  90. GRB041016,optical observation
  91. GRB 041016: Optical limits
  92. GRB 041016:Optical limit during first minute
  93. GRB 041015: Optical Observations at Rikubetsu
  94. GRB 041016: Optical limit
  95. GRB 041015 R band observations
  96. GRB040924, BVRcIc field calibration
  97. GRB041015,optical observation
  98. GRB041006: Fading X-ray Afterglow Observed with Chandra
  99. GRB 041015 - A long GRB detected by INTEGRAL
  100. GRB041006: VLT observations of the afterglow and host galaxy

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