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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"

22105 results found.

  1. GRB050209: TAROT optical observations
  2. GRB 050209(=U11568): Duration and spectrum
  3. short/hard GRB 050202, optical observations
  4. GRB050209: REM optical observations
  5. GRB 050209 I-band observation
  6. GRB 050209 Optical observations
  7. GRB050209: P60 Optical Observations
  8. GRB 050128: Radio observations
  9. GRB 050129: Optical observations
  10. GRB 050202: Short burst detected by Swift-BAT
  11. GRB 050128 Optical observation with REM
  12. GRB 050128: near-infrared observations with REM
  13. GRB050128,optical observations
  14. GRB050128 Swift-BAT observations
  15. GRB 050128: Swift XRT prompt afterglow position
  16. GRB050126: MASTER optical limit for KECK OT
  17. GRB050126: Burst Parameters Measured by BAT
  18. GRB050126: MASTER optical observations
  19. GRB050124: No Swift UVOT Detection of Afterglow Emission
  20. GRB 050124 I-band observation
  21. GRB050124,optical observation
  22. GRB050124: Updated Swift XRT Position and Fluxes
  23. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  24. GRB050124: Refined BAT position, spectral and fluence information
  25. GRB050124: Swift-BAT position of a double-peaked burst
  26. GRB 050123 : I-band follow-up observation
  27. GRB050123: optical limit 1.8h before GRB
  28. GRB050123,optical observation
  29. GRB 050123: KAIT observations
  30. CFHTLS optical transient unlikely to be a GRB
  31. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  32. GRB050117b: Swift-BAT detection of a weak burst
  33. GRB050117: MASTER optical observations
  34. MASTER:GRB050117 SWIFT
  35. GRB050117: Swift-BAT detection of a long multi-peaked burst
  36. GRB050117: Swift XRT Position
  37. Triangulation of Short Hard GRB050112 (large error box)
  38. SGR1806-20: Swift-BAT observations of two additional bursts
  39. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  40. Further VLA observations of SGR 1806-20
  41. SGR 1806-20 and extragalactic short-duration GRBs
  42. Further ATCA observations of SGR 1806-20
  43. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  44. SGR 1806-20, RHESSI observations of the 041227 giant flare
  45. Second-epoch VLA observations of SGR 1806-20
  46. SGR1806 VLA Observations
  47. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  48. GRB 041217: Optical observations
  49. GRB041228: ROTSE-III Optical Observations
  50. GRB041228: Swift-BAT detection of a burst
  51. GRB041219; RXTE ASM Observations
  52. GRB041226: ROTSE-III Optical Observations
  53. GRB041226: Swift-BAT detection of a burst
  54. GRB041223: decay of the afterglow
  55. GRB041224: ROTSE-III Optical Observations
  56. GRB 041224: near-infrared observations with REM
  57. GRB041224: Swift-BAT detection of a soft burst
  58. GRB041223: optical and NIR observations with REM
  59. GRB 041219: TAROT optical observations
  60. GRB 041218: TAROT optical observations
  61. GRB 041223: J-band observations of the afterglow
  62. GRB 041219c: PROMPT Observations
  63. GRB041223: ROTSE-III Optical Observations
  64. GRB041223: Swift-BAT detection of a bright long burst
  65. GRB 041218: optical observations
  66. GRB 041219 : optical follow-up observations
  67. GRB 041218 Optical Observations
  68. GRB041219: Continued NIR Observations
  69. GRB 041219 ,optical observation
  70. GRB 041219: Radio Afterglow Detection
  71. GRB 041218 : Radio Observations
  72. GRB 041218: R-band optical observations
  73. GRB041218: optical observations
  74. GRB041219: Confirmed NIR Afterglow
  75. Swift-BAT detection of the bright long burst GRB041219
  76. GRB 041219: Infrared Afterglow Candidate
  77. GRB041219, BVRcIc field calibration
  78. GRB 041219: Infrared Afterglow Candidate
  79. GRB041218, BVRcIc field calibration
  80. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  81. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  82. GRB 041217: PROMPT Observations
  83. GRB041217: optical limit 30 min after GRB
  84. GRB 041217: LCO40 Optical Observations and Possible Candidates
  85. GRB 041218 - A long GRB detected by integral
  86. GRB041217: NIR and optical observations with REM
  87. GRB041217: P60 Optical Observations
  88. GRB041217: Infrared Observations
  89. GRB041217: The First GRB Located On-Board Swift
  90. GRB041211: Faulkes Telescope continued optical monitoring
  91. Optical transient (GRB?) in Lynx
  92. GRB041211: RAPTOR observations
  93. GRB041211: Ashra Prototype optical observation
  94. GRB041211, BVRcIc field calibration
  95. GRB041211,optical observation
  96. GRB 041211: Infrared Observations
  97. GRB 041211: KAIT observations
  98. GRB 041211: Optical follow-up in East Asian region
  99. Triangulation of short GRB 041116 (large error box)
  100. GRB 040924: Afterglow Color

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