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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"

32503 results found.

  1. GRB050124,optical observation
  2. GRB 050124 : Lulin R-band follow-up observation
  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 limit 1.8h before GRB
  7. GRB 050123: KAIT observations
  8. GRB050123: P60 Observations
  9. CFHTLS optical transient unlikely to be a GRB
  10. GRB050117a: Radio Observations
  11. GRB050117a: Refined analysis
  12. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  13. GRB050117: Palomar WIRC Ks-band observations
  14. GRB050117: optical observation
  15. GRB 050117, I-band observations
  16. GRB 050117: Optical observation
  17. GRB050117: Refined XRT position
  18. GRB050117: MASTER optical observations
  19. MASTER:GRB050117 SWIFT
  20. GRB050117: Swift-BAT detection of a long multi-peaked burst
  21. SGR 1806-20: RXTE/PCA pulse frequency during flare
  22. SGR 1806-20: Further low frequency GMRT results
  23. SGR1806-20: Swift-BAT observations of two additional bursts
  24. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  25. Further VLA observations of SGR 1806-20
  26. SGR 1806-20 and extragalactic short-duration GRBs
  27. Fourth Epoch VLA observations of SGR 1806-20
  28. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  29. SGR 1806-20: Temporal and Spectral behavior of radio transient
  30. ATCA observations of SGR 1806-20
  31. SGR 1806-20, RHESSI observations of the 041227 giant flare
  32. Third epoch observations of SGR 1806-20 with VLA
  33. Second Epoch VLA observations of SGR 1806-20
  34. Second-epoch VLA observations of SGR 1806-20
  35. SGR1806: Detection of a Sudden Ionospheric Disturbance
  36. DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20
  37. VLA observations of SGR 1806-20
  38. SGR1806 VLA Observations
  39. VLA observations of SGR 1806-20
  40. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  41. GRB 041217: Optical observations
  42. GRB041219, early time observations
  43. The giant outburst from SGR 1806-20
  44. IPN localization of giant flare from SGR1806-20
  45. GRB041228: ROTSE-III Optical Observations
  46. GRB041219; RXTE ASM Observations
  47. NIR Observations of GRB 041219
  48. GRB041226: ROTSE-III Optical Observations
  49. GRB041223: decay of the afterglow
  50. GRB041224: ROTSE-III Optical Observations
  51. GRB 041224: near-infrared observations with REM
  52. GRB 041223: XRT afterglow spectrum and light curve
  53. GRB 041223 Fluence measured by Swift-BAT
  54. GRB041223: optical and NIR observations with REM
  55. Swift-BAT Time History of GRB041219
  56. GRB 041219: TAROT optical observations
  57. GRB 041223: J-band observations of the afterglow
  58. GRB 041223: Detection of Optical Transient with LCO40
  59. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  60. GRB 041219c: PROMPT Observations
  61. GRB041223: ROTSE-III Optical Observations
  62. GRB 041218: optical observations
  63. Very high activity of SGR 1806-20
  64. GRB 041219: Second Epoch WSRT Radio Observations
  65. GRB 041219: WSRT Radio Afterglow Detection
  66. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  67. GRB 041218: Optical observations
  68. GRB 041219 : optical follow-up observations
  69. Deep RAPTOR observations during GRB 041219
  70. GRB 041218 Optical Observations
  71. GRB 041219 Optical Observations
  72. GRB041219: Optical Afterglow Detection
  73. GRB041219: Continued NIR Observations
  74. GRB 041219: Radio Afterglow Detection
  75. GRB 041218 : Radio Observations
  76. GRB 041218: R-band optical observations
  77. GRB041218: Liverpool Telescope optical observations
  78. GRB041218: optical observations
  79. GRB041219: Confirmed NIR Afterglow
  80. Swift-BAT detection of the bright long burst GRB041219
  81. GRB 041218: Optical Observation
  82. GRB 041219: Infrared Afterglow Candidate
  83. GRB041219, BVRcIc field calibration
  84. GRB 041219: Infrared Afterglow Candidate
  85. GRB041218, BVRcIc field calibration
  86. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  87. GRB 041217: PROMPT Observations
  88. GRB041218: optical observations
  89. GRB041217: optical limit 30 min after GRB
  90. GRB 041218; optical candidate
  91. GRB 041218: Optical observations
  92. GRB 041217: LCO40 Optical Observations and Possible Candidates
  93. GRB041217: Optical Observations
  94. GRB041217: NIR and optical observations with REM
  95. GRB041217: Infrared Observations
  96. GRB041217: The First GRB Located On-Board Swift
  97. GRB041211: Faulkes Telescope continued optical monitoring
  98. Optical Transient in Lynx not a GRB
  99. Optical transient (GRB?) in Lynx
  100. GRB041211: Continued P60 Observations

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