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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"

15247 results found.

  1. GRB050117: Swift XRT Position
  2. SGR 1806-20: RXTE/PCA pulse frequency during flare
  3. SGR 1806-20: Further low frequency GMRT results
  4. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  5. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  6. SGR 1806-20, RHESSI observations of the 041227 giant flare
  7. Second Epoch VLA observations of SGR 1806-20
  8. Second-epoch VLA observations of SGR 1806-20
  9. SGR1806: Detection of a Sudden Ionospheric Disturbance
  10. VLA observations of SGR 1806-20
  11. VLA observations of SGR 1806-20
  12. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  13. GRB 041217: Optical observations
  14. The giant outburst from SGR 1806-20
  15. IPN localization of giant flare from SGR1806-20
  16. NIR Observations of GRB 041219
  17. GRB041223: decay of the afterglow
  18. GRB 041223 Fluence measured by Swift-BAT
  19. GRB041223: optical and NIR observations with REM
  20. Swift-BAT Time History of GRB041219
  21. GRB 041223: J-band observations of the afterglow
  22. GRB041223: Swift-BAT detection of a bright long burst
  23. Very high activity of SGR 1806-20
  24. GRB 041219: WSRT Radio Afterglow Detection
  25. GRB 041218: Optical observations
  26. GRB 041219 : optical follow-up observations
  27. GRB041219: Continued NIR Observations
  28. GRB 041219 ,optical observation
  29. GRB 041219: Radio Afterglow Detection
  30. GRB 041218 : Radio Observations
  31. GRB 041218: R-band optical observations
  32. GRB041218: optical observations
  33. GRB041219: Confirmed NIR Afterglow
  34. GRB 041218: Optical Observation
  35. GRB 041219: Infrared Afterglow Candidate
  36. GRB 041219: Infrared Afterglow Candidate
  37. GRB041218: optical observations
  38. GRB041217: P60 Optical Observations
  39. Optical Transient in Lynx not a GRB
  40. GRB041211: Ashra Prototype optical observation
  41. GRB041211, Faulkes Telescope optical observation
  42. GRB041211,optical observation
  43. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  44. GRB 041006: Optical Observations
  45. GRB041006: RTT150 Optical Observations
  46. GRB041006: RTT150 Optical Observations
  47. GRB041016,optical observation
  48. GRB 041016: Optical limits
  49. GRB041015,optical observation
  50. GRB041006: Fading X-ray Afterglow Observed with Chandra
  51. GRB 041006 R observations in Loiano
  52. GRB 040924: VLT spectroscopy
  53. Search for SN light in XRF 040912 with MEGACAM
  54. GRB 041006 Optical afterglow observations
  55. IBAS GRB Alert # 2010
  56. GRB 041006: BR observations with VATT
  57. GRB 041006 : optical follow-up observation at Lulin Observatory
  58. GRB 041006 : Optical follow-up observation at TAROT
  59. GRB041006: Optical photometry and spectroscopy at TNG
  60. GRB041006 (=HETE3570): optical observations
  61. ROTSE-IIIa Observations of GRB 041006
  62. GRB041006, optical observation
  63. GRB041006, submillimetre observations
  64. GRB041006,optical observation
  65. GRB 041006 : Optical follow-up observation at KISO
  66. GRB 041006: Finding chart
  67. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  68. SGR 1806-20 still active
  69. GRB040929,optical observation
  70. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  71. GRB040924, RTT150 optical observation
  72. GRB040924: KAIT observations
  73. GRB040924: Afterglow magnitude at t=17.5hr
  74. GRB040924 : Optical candidate observations at Lulin observatory
  75. GRB040924 : Optical candidate observations at Lulin observatory
  76. GRB 040924, optical follow-up
  77. IPN triangulation of GRB040924 (H3564)
  78. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  79. XRF040916: continuing decay of OT
  80. GRB040912(=H3557): Candidate Optical Afterglow
  81. XRF040916, optical observations
  82. XRF 040912 (=H3557): Spectral and Temporal Properties
  83. XRF040916: optical follow-up observations
  84. GRB040916: Archival optical observations
  85. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  86. GRB040916: Optical observations
  87. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  88. GRB040912 (= H3557): Chandra Observations Scheduled
  89. GRB 040912, BVRI observations
  90. Optical observations of field of GRB040912
  91. GRB040903 - A XRF?
  92. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  93. Possible GRB 040903 detected with INTEGRAL
  94. XMM-Newton Images of GRB 040827
  95. GRB 040827: K imaging - no evidence of variability
  96. GRB 040827: Detection of NIR afterglow
  97. GRB 040827: RTT150 optical observations
  98. GRB040827 optical observations
  99. GRB 040827 - Refined position
  100. GRB040825B (=H3510): An XRF Localized in Real Time by HETE

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