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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"

20572 results found.

  1. GRB 020124 Optical Observations
  2. IPN observations of SGR1806-20
  3. GRB 020124: Optical afterglow
  4. HETE 1896: Optical observations
  5. GRB optical counterpart candidate in GCN 1217 is M dwarf
  6. Possible optical counterpart to a GRB
  7. GRB011212, Optical Observations
  8. Optical polarization observations for GRB011211
  9. GRB 011211: Detection of the Probable Host Galaxy
  10. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  11. Color indices of the afterglow of GRB011211
  12. GRB011212: Optical observations at Gunma
  13. GRB 011130: Optical Observations of X-ray and Radio Sources
  14. GRB 011130, Radio/X-ray Comparison
  15. GRB011212: Optical observations
  16. GRB 011212: optical observation at Asiago
  17. GRB 011211: TNG Spectroscopic Observations
  18. GRB 011211, Optical Observations
  19. GRB011212: Optical observations
  20. GRB 011211 Optical Observations: Likely Afterglow
  21. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  22. GRB 011130: Optical Observations of Chandra Sources
  23. GRB 011130: Optical Observations of Chandra sources
  24. GRB011130 (XRF011130) Chandra Observations
  25. GRB 011130: Magellan spectroscopy
  26. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  27. GRB011130, optical observations
  28. GRB 011130, K band observations
  29. GRB011130, optical observations
  30. GRB011130 (XRF011130) optical observations
  31. GRB011130 (XRF011130) SDSS PT i-band observations
  32. XRF011130: Infrared Observations
  33. GRB011130, Radio Observations
  34. GRB011130 (=XRF011130), Optical Observations
  35. XRF011130: NEAT Optical Observations
  36. GRB001109, Radio Monitoring
  37. GRB 011121
  38. GRB 011121: J-band observations
  39. GRB 011121: NIR observations, host galaxy?
  40. GRB010921 - Milagro GeV/TeV Observations
  41. GRB 011121: HST Scheduled
  42. GRB011121: fainter still
  43. GRB011121: UBRI Observations
  44. GRB011121
  45. GRB 011121: Radio Observations
  46. GRB011121: continued decay
  47. GRB 011121: Detection of Bright IR Counterpart
  48. GRB011121: possible redshift, continued decay
  49. GRB011121: fading behavior
  50. GRB011121: possible optical counterpart
  51. XRF011030: J and K band observations
  52. XRF011030: Chandra Observations
  53. GRB 011030: K-band observations
  54. GRB011030: Z-band observations
  55. GRB 011030 R band observations
  56. The X-ray Flash 011030 ('GRB 011030')
  57. Non-triggered burst 011030 ("GRB 011030")
  58. The Radio Afterglow from the X-ray Rich GRB 011030
  59. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  60. GRB 970828: HST Observations of the Host Galaxy
  61. GRB 000131: HST Detection of the Host Galaxy
  62. GRB 970828: HST Observations of the Host Galaxy
  63. GRB010921, optical observation
  64. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  65. GRB011019: Subaru Optical Observations
  66. GRB 011030 I-band Observations
  67. GRB 011030 K-band Observations
  68. GRB010921, optical observations
  69. GRB 011030, WSRT radio observations
  70. GRB 011030, Radio observations
  71. GRB 011030, R-band observations
  72. GRB011019: NEAT Optical Observations
  73. GRB011019: ROTSE-III optical observations
  74. GRB 010921, I-band observations
  75. GRB011019: Optical observations
  76. GRB011019, optical observations -- correction
  77. GRB011019, optical observations
  78. GRB010921: Spectroscopy of the Host Galaxy
  79. GRB 010921: The afterglow of HETE #1761
  80. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  81. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  82. GRB010928(=H1770): Localization of a Long GRB by HETE
  83. GRB010921, negative optical observations
  84. GRB010921 Optical Observations
  85. HETE Trigger #1760 (GRB 010920B?): a new optical source
  86. HETE Trigger #1759 (GRB 010920?) optical observations
  87. GRB001109, Host Galaxy Astrometry
  88. GRB000926, Host Galaxy Observations
  89. GRB001109, Host Galaxy Spectroscopic Observations
  90. GRB000926 Host Galaxy Observations
  91. GRB 010222: HST observations -- host galaxy and late-time decay
  92. GRB 010222 - WHT BVRI images
  93. GRB 010629 Optical Observations
  94. GRB010629: Optical Observations
  95. SGR1900+14: High Fluence Burst Localized by HETE
  96. GRB010629, optical observations
  97. GRB010629: A Burst Localized by HETE
  98. SGR1900+14: Second Burst Localized by HETE
  99. SGR1900+14: A Burst Localized by HETE
  100. SGR1806-20: A Second, Intense Burst Localized by HETE

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