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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"

15714 results found.

  1. GRB020127 Optical Observations
  2. Type Ib/c SN2002ap (SN/GRB?)
  3. Type Ib/c SN2002ap (SN/GRB?) Radio Observations
  4. GRB020124, optical observations
  5. GRB020127: Optical observations
  6. IPN triangulation of GRB020127 (=H1902)
  7. GRB020127 Optical Observations -- Erratum to GCN 1230
  8. GRB010921 Optical Observations
  9. GRB020127(=H1902): Localization of a Double-Peaked GRB by HETE
  10. GRB020124: Optical observations
  11. VLT observations of GRB 020124: The fading optical/near-infrared afterglow
  12. GRB020124: Optical observations
  13. GRB 020124: Optical observations
  14. GRB 020124 Optical Observations
  15. IPN triangulation of GRB020124 (HETE 1896)
  16. GRB 020124: Optical afterglow
  17. GRB020124(=H1896): Localization of a Long GRB by HETE
  18. HETE 1896: Optical observations
  19. GRB optical counterpart candidate in GCN 1217 is M dwarf
  20. Possible optical counterpart to a GRB
  21. GRB011212, Optical Observations
  22. Optical polarization observations for GRB011211
  23. Color indices of the afterglow of GRB011211
  24. GRB011212: Optical observations at Gunma
  25. GRB 011211, spectrum and optical photometry
  26. GRB 011130: Optical Observations of X-ray and Radio Sources
  27. GRB 011130, Radio/X-ray Comparison
  28. GRB011212: Optical observations
  29. GRB 011212: optical observation at Asiago
  30. GRB 011211: Evidence for an Optical Break
  31. optical follow-up of GRB(XRF) 011211
  32. GRB 011212: optical observation at Oslo (relayed)
  33. GRB 011211: Optical Spectroscopy
  34. GRB 011211, Optical Observations
  35. GRB011212, BVRI field photometry
  36. GRB011211, BVRI field photometry
  37. GRB011212: Optical observations
  38. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  39. Fading of the optical source associated of XRF 011211
  40. GRB 011211 Optical Observations: Likely Afterglow
  41. GRB 011130: Optical Observations of Chandra Sources
  42. GRB 011130: Optical Observations of Chandra sources
  43. GRB 011130: Magellan spectroscopy
  44. GRB011130, optical observations
  45. GRB 011130, K band observations
  46. GRB011130, optical observations
  47. GRB011130 (=XRF011130): Second Revised Localization by HETE
  48. GRB 011130 I-band Observation
  49. GRB011130 (XRF011130) optical observations
  50. XRF011130: Infrared Observations
  51. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  52. GRB011130 (=XRF011130), Optical Observations
  53. XRF011130: NEAT Optical Observations
  54. GRB011130 (=XRF011130): Revised Localization of an X-ray
  55. GRB001109, Radio Monitoring
  56. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  57. GRB 011121: J-band observations
  58. GRB 011121: HST Scheduled
  59. GRB011121: UBRI Observations
  60. GRB 011121: Radio Observations
  61. GRB 011121 J-Band Astrometry
  62. GRB011121: continued decay
  63. GRB011121: possible redshift, continued decay
  64. GRB011121: fading behavior
  65. GRB011121: possible optical counterpart
  66. GRB011030, optical observation
  67. GRB 011030 I-band Observation
  68. The X-ray Flash 011030 ('GRB 011030')
  69. Non-triggered burst 011030 ("GRB 011030")
  70. The Radio Afterglow from the X-ray Rich GRB 011030
  71. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  72. GRB 970828: HST Observations of the Host Galaxy
  73. GRB 000131: HST Detection of the Host Galaxy
  74. GRB 970828: HST Observations of the Host Galaxy
  75. GRB010921, optical observation
  76. GRB 011019 optical observation
  77. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  78. GRB011019: Subaru Optical Observations
  79. GRB010921, optical observations
  80. GRB 011030, R-band observations
  81. GRB 010921: Possible supernova component
  82. GRB011019: NEAT Optical Observations
  83. GRB011019: ROTSE-III optical observations
  84. GRB010921, optical observation at early time
  85. GRB011019: Optical observations
  86. GRB011019, optical observations -- correction
  87. GRB011019, optical observations
  88. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  89. GRB 010921: The afterglow of HETE #1761
  90. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  91. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  92. GRB010928(=H1770): Localization of a Long GRB by HETE
  93. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  94. GRB010921, negative optical observations
  95. GRB010921 field photometry
  96. GRB010921 Optical Observations
  97. IPN triangulation of GRB010921 (=H1761)
  98. H1761: A Bright GRB Detected by HETE
  99. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  100. HETE Trigger #1760 (GRB 010920B?): a new optical source

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