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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"

23584 results found.

  1. GRB 020124 Optical Observations
  2. IPN triangulation of GRB020124 (HETE 1896)
  3. IPN observations of SGR1806-20
  4. GRB 020124: Optical afterglow
  5. GRB020124(=H1896): Localization of a Long GRB by HETE
  6. GRB optical counterpart candidate in GCN 1217 is M dwarf
  7. GRB011212, Optical Observations
  8. GRB011211: BeppoSAX/GRBM data
  9. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  10. GRB011212: Optical observations at Gunma
  11. GRB 011211, spectrum and optical photometry
  12. GRB 011130, Radio/X-ray Comparison
  13. GRB011212: Optical observations
  14. GRB 011212: optical observation at Asiago
  15. GRB 011211: Evidence for an Optical Break
  16. GRB 011211: TNG Spectroscopic Observations
  17. optical follow-up of GRB(XRF) 011211
  18. GRB 011212: optical observation at Oslo (relayed)
  19. GRB 011211: Optical Spectroscopy
  20. GRB 011211, Optical Observations
  21. GRB011212, BVRI field photometry
  22. GRB011211, BVRI field photometry
  23. GRB011212: Optical observations
  24. GRB 011211: BVRi-band photometry
  25. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  26. XMM-Newton observation of GRB011211
  27. GRB 011211 Optical Observations: Likely Afterglow
  28. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  29. GRB 011130: Magellan spectroscopy
  30. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  31. GRB011130, optical observations
  32. GRB011130, optical observations
  33. GRB011130 (=XRF011130): Second Revised Localization by HETE
  34. GRB011130 (XRF011130) optical observations
  35. GRB011130 (XRF011130) SDSS PT i-band observations
  36. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  37. GRB011130 (=XRF011130), Optical Observations
  38. XRF011130: NEAT Optical Observations
  39. GRB011130 (=XRF011130): Revised Localization of an X-ray
  40. GRB 011121
  41. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  42. GRB 011121: J-band observations
  43. GRB011121: UBRI Observations
  44. GRB011121
  45. GRB 011121: Radio Observations
  46. GRB011121: possible redshift, continued decay
  47. GRB011121: fading behavior
  48. GRB011121: possible optical counterpart
  49. IPN triangulation of GRB011121
  50. GRB 011030: TNG K-band observation
  51. GRB011030, optical observation
  52. GRB 011030: K-band observations
  53. GRB011030: Z-band observations
  54. Non-triggered burst 011030 ("GRB 011030")
  55. GRB010921, optical observation
  56. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  57. GRB011019: Subaru Optical Observations
  58. GRB010921, optical observations
  59. GRB011030: radio search
  60. GRB 011030, R-band observations
  61. GRB011019: NEAT Optical Observations
  62. GRB011019: ROTSE-III optical observations
  63. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  64. GRB010921: Spectroscopy of the Host Galaxy
  65. GRB 010921: The afterglow of HETE #1761
  66. GRB010923 as seen by BeppoSAX GRBM
  67. GRB010928(=H1770): Localization of a Long GRB by HETE
  68. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  69. GRB010921 field photometry
  70. GRB010921 Optical Observations
  71. IPN triangulation of GRB010921 (=H1761)
  72. H1761: A Bright GRB Detected by HETE
  73. GRB000926, Host Galaxy Observations
  74. GRB001109, Host Galaxy Spectroscopic Observations
  75. Probable SGR or Short Duration GRB Detected by HETE
  76. GRB000926 Host Galaxy Observations
  77. GRB 010222: HST observations -- host galaxy and late-time decay
  78. BeppoSAX/GRBM detection of GRB 010801
  79. GCN and HETE status
  80. BeppoSAX/GRBM detection of GRB010728
  81. GRB 010222 - WHT BVRI images
  82. SGR1900+14 burst seen by HETE: BeppoSAX data
  83. GRB 010629 Optical Observations
  84. SGR1900+14: High Fluence Burst Localized by HETE
  85. IPN triangulation of GRB010629
  86. GRB010629: A Burst Localized by HETE
  87. SGR1900+14: Second Burst Localized by HETE
  88. SGR1900+14: A Burst Localized by HETE
  89. Possible burst from SGR1806-20
  90. IPN detection of SGR1900+14
  91. SGR1806-20: A Second, Intense Burst Localized by HETE
  92. SGR1806-20: Localization by HETE
  93. GRB000418: HST/STIS Second-epoch Observations
  94. X-ray precursors to the large flare from SGR 1900+14
  95. GRB010427, Gamma Ray Observations
  96. SGR 1900+14 : RXTE observations
  97. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  98. SGR1900+14
  99. GRB 010222 /corrections to VBT data
  100. Millimeter observation of SGR 1900+14

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