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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"

27396 results found.

  1. GRB 050215b: Swift XRT Source Variability
  2. GRB 050215B: candidate afterglow
  3. GRB 050215b : Lulin follow-up observation
  4. GRB 050215b, BOOTES-2 simultaneous optical observations
  5. GRB050215A: ROTSE-III Optical Observations
  6. GRB050209: TAROT optical observations
  7. GRB 050209(=U11568): Duration and spectrum
  8. GRB050209: REM optical observations
  9. GRB 050209 I-band observation
  10. GRB 050209 Optical observations
  11. GRB050209: P60 Optical Observations
  12. GRB 050128: Radio observations
  13. Further analysis of the short Swift-BAT GRB 050202
  14. GRB 050202: Short burst detected by Swift-BAT
  15. GRB 050128 Optical observation with REM
  16. SGR1806-20: Swift-BAT detection of a large normal burst
  17. GRB 050128: near-infrared observations with REM
  18. GRB050128,optical observations
  19. GRB050128 Swift-BAT observations
  20. GRB 050128: Swift XRT prompt afterglow position
  21. GRB050126: MASTER optical limit for KECK OT
  22. GRB050126: Burst Parameters Measured by BAT
  23. GRB050126: MASTER optical observations
  24. GRB 050124 I-band observation
  25. GRB050124,optical observation
  26. GRB 050124 : Lulin R-band follow-up observation
  27. GRB050124: Updated Swift XRT Position and Fluxes
  28. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  29. GRB050124: Refined BAT position, spectral and fluence information
  30. GRB 050123 : I-band follow-up observation
  31. GRB050123,optical observation
  32. GRB 050123: KAIT observations
  33. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  34. GRB050117: Refined XRT position
  35. GRB050117: MASTER optical observations
  36. MASTER:GRB050117 SWIFT
  37. GRB050117: Swift XRT Position
  38. Triangulation of Short Hard GRB050112 (large error box)
  39. SGR 1806-20: Further VLA Observations
  40. SGR1806-20: Swift-BAT observations of two additional bursts
  41. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  42. Further VLA observations of SGR 1806-20
  43. SGR 1806-20 and extragalactic short-duration GRBs
  44. Further ATCA observations of SGR 1806-20
  45. Fourth Epoch VLA observations of SGR 1806-20
  46. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  47. ATCA observations of SGR 1806-20
  48. SGR 1806-20, RHESSI observations of the 041227 giant flare
  49. Third epoch observations of SGR 1806-20 with VLA
  50. Second Epoch VLA observations of SGR 1806-20
  51. Second-epoch VLA observations of SGR 1806-20
  52. SGR1806 VLA Observations
  53. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  54. GRB 041217: Optical observations
  55. GRB041228: Swift-BAT detection of a burst
  56. GRB041219; RXTE ASM Observations
  57. NIR Observations of GRB 041219
  58. GRB041226: Swift-BAT detection of a burst
  59. GRB041223: decay of the afterglow
  60. GRB 041224: near-infrared observations with REM
  61. GRB 041223 Fluence measured by Swift-BAT
  62. GRB041223: optical and NIR observations with REM
  63. Swift-BAT Time History of GRB041219
  64. GRB 041219: TAROT optical observations
  65. GRB 041218: TAROT optical observations
  66. GRB 041223: J-band observations of the afterglow
  67. GRB 041219c: PROMPT Observations
  68. GRB041223: Swift-BAT detection of a bright long burst
  69. GRB 041218: optical observations
  70. GRB 041219 : optical follow-up observations
  71. Deep RAPTOR observations during GRB 041219
  72. GRB 041218 Optical Observations
  73. GRB041219: Continued NIR Observations
  74. GRB 041219 ,optical observation
  75. GRB 041219: Radio Afterglow Detection
  76. GRB 041218 : Radio Observations
  77. GRB 041218: R-band optical observations
  78. GRB041218: optical observations
  79. GRB041219: Confirmed NIR Afterglow
  80. Swift-BAT detection of the bright long burst GRB041219
  81. GRB 041219: Infrared Afterglow Candidate
  82. GRB041219, BVRcIc field calibration
  83. GRB 041219: Infrared Afterglow Candidate
  84. GRB041218, BVRcIc field calibration
  85. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  86. GRB 041219 - A long GRB detected by INTEGRAL
  87. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  88. GRB 041217: PROMPT Observations
  89. GRB 041217: LCO40 Optical Observations and Possible Candidates
  90. GRB 041218 - A long GRB detected by integral
  91. GRB041217: NIR and optical observations with REM
  92. GRB041217: Infrared Observations
  93. GRB041217: The First GRB Located On-Board Swift
  94. GRB041211: Faulkes Telescope continued optical monitoring
  95. Optical Transient in Lynx not a GRB
  96. Optical transient (GRB?) in Lynx
  97. GRB041211: RAPTOR observations
  98. GRB041211: Ashra Prototype optical observation
  99. GRB041211, BVRcIc field calibration
  100. GRB041211,optical observation

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