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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"

27400 results found.

  1. GRB 050219b: Swift XRT Position
  2. GRB 050219: Swift-BAT detection of a burst
  3. GRB 050215b: XRT confirmation of IR afterglow candidate
  4. GRB050215b: P60 Optical Observations
  5. GRB 050215b: Swift XRT Source Variability
  6. GRB 050215B: candidate afterglow
  7. GRB 050215b : Lulin follow-up observation
  8. GRB 050215b, BOOTES-2 simultaneous optical observations
  9. GRB050215A: ROTSE-III Optical Observations
  10. GRB050209: TAROT optical observations
  11. GRB 050209(=U11568): Duration and spectrum
  12. GRB050209: REM optical observations
  13. GRB 050209 I-band observation
  14. GRB 050209 Optical observations
  15. GRB050209: P60 Optical Observations
  16. GRB 050128: Radio observations
  17. Further analysis of the short Swift-BAT GRB 050202
  18. GRB 050202: Short burst detected by Swift-BAT
  19. GRB 050128 Optical observation with REM
  20. SGR1806-20: Swift-BAT detection of a large normal burst
  21. GRB 050128: near-infrared observations with REM
  22. GRB050128,optical observations
  23. GRB050128 Swift-BAT observations
  24. GRB 050128: Swift XRT prompt afterglow position
  25. GRB050126: MASTER optical limit for KECK OT
  26. GRB050126: Burst Parameters Measured by BAT
  27. GRB050126: MASTER optical observations
  28. GRB 050124 I-band observation
  29. GRB050124,optical observation
  30. GRB 050124 : Lulin R-band follow-up observation
  31. GRB050124: Updated Swift XRT Position and Fluxes
  32. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  33. GRB050124: Refined BAT position, spectral and fluence information
  34. GRB 050123 : I-band follow-up observation
  35. GRB050123,optical observation
  36. GRB 050123: KAIT observations
  37. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  38. GRB050117: Refined XRT position
  39. GRB050117: MASTER optical observations
  40. MASTER:GRB050117 SWIFT
  41. GRB050117: Swift XRT Position
  42. Triangulation of Short Hard GRB050112 (large error box)
  43. SGR 1806-20: Further VLA Observations
  44. SGR1806-20: Swift-BAT observations of two additional bursts
  45. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  46. Further VLA observations of SGR 1806-20
  47. SGR 1806-20 and extragalactic short-duration GRBs
  48. Further ATCA observations of SGR 1806-20
  49. Fourth Epoch VLA observations of SGR 1806-20
  50. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  51. ATCA observations of SGR 1806-20
  52. SGR 1806-20, RHESSI observations of the 041227 giant flare
  53. Third epoch observations of SGR 1806-20 with VLA
  54. Second Epoch VLA observations of SGR 1806-20
  55. Second-epoch VLA observations of SGR 1806-20
  56. SGR1806 VLA Observations
  57. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  58. GRB 041217: Optical observations
  59. GRB041228: Swift-BAT detection of a burst
  60. GRB041219; RXTE ASM Observations
  61. NIR Observations of GRB 041219
  62. GRB041226: Swift-BAT detection of a burst
  63. GRB041223: decay of the afterglow
  64. GRB 041224: near-infrared observations with REM
  65. GRB 041223 Fluence measured by Swift-BAT
  66. GRB041223: optical and NIR observations with REM
  67. Swift-BAT Time History of GRB041219
  68. GRB 041219: TAROT optical observations
  69. GRB 041218: TAROT optical observations
  70. GRB 041223: J-band observations of the afterglow
  71. GRB 041219c: PROMPT Observations
  72. GRB041223: Swift-BAT detection of a bright long burst
  73. GRB 041218: optical observations
  74. GRB 041219 : optical follow-up observations
  75. Deep RAPTOR observations during GRB 041219
  76. GRB 041218 Optical Observations
  77. GRB041219: Continued NIR Observations
  78. GRB 041219 ,optical observation
  79. GRB 041219: Radio Afterglow Detection
  80. GRB 041218 : Radio Observations
  81. GRB 041218: R-band optical observations
  82. GRB041218: optical observations
  83. GRB041219: Confirmed NIR Afterglow
  84. Swift-BAT detection of the bright long burst GRB041219
  85. GRB 041219: Infrared Afterglow Candidate
  86. GRB041219, BVRcIc field calibration
  87. GRB 041219: Infrared Afterglow Candidate
  88. GRB041218, BVRcIc field calibration
  89. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  90. GRB 041219 - A long GRB detected by INTEGRAL
  91. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  92. GRB 041217: PROMPT Observations
  93. GRB 041217: LCO40 Optical Observations and Possible Candidates
  94. GRB 041218 - A long GRB detected by integral
  95. GRB041217: NIR and optical observations with REM
  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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