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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"

26373 results found.

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

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