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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"

36155 results found.

  1. IPN observations of SGR1806-20
  2. GRB 020124: Optical afterglow
  3. GRB020124(=H1896): Localization of a Long GRB by HETE
  4. GRB optical counterpart candidate in GCN 1217 is M dwarf
  5. Possible optical counterpart to a GRB
  6. GRB011212, Optical Observations
  7. GRB 011211: Detection of the Probable Host Galaxy
  8. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  9. GRB 011211, spectrum and optical photometry
  10. GRB 011130: Optical Observations of X-ray and Radio Sources
  11. GRB 011130, Radio/X-ray Comparison
  12. GRB 011212: optical observation at Asiago
  13. GRB 011211: Evidence for an Optical Break
  14. GRB 011211: TNG Spectroscopic Observations
  15. optical follow-up of GRB(XRF) 011211
  16. GRB 011212: optical observation at Oslo (relayed)
  17. GRB 011211: Optical Spectroscopy
  18. GRB 011211, Optical Observations
  19. GRB011212, BVRI field photometry
  20. GRB011211, BVRI field photometry
  21. GRB011212: Optical observations
  22. GRB 011211: BVRi-band photometry
  23. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  24. Fading of the optical source associated of XRF 011211
  25. GRB 011211 Optical Observations: Likely Afterglow
  26. BeppoSAX Alert: GRB011211(=XRF011211)
  27. GRB 011130: Optical Observations of Chandra Sources
  28. GRB 011130: Optical Observations of Chandra sources
  29. GRB 011130: Magellan spectroscopy
  30. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  31. GRB011130, optical observations
  32. GRB 011130, K band observations
  33. GRB011130, optical observations
  34. GRB 011130 I-band Observation
  35. GRB011130 (XRF011130) optical observations
  36. GRB011130 (XRF011130) SDSS PT i-band observations
  37. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  38. XRF011130: NEAT Optical Observations
  39. GRB011130 (=XRF011130): Revised Localization of an X-ray
  40. GRB001109, Radio Monitoring
  41. GRB 011121: Errata URL
  42. GRB 011121
  43. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  44. GRB 011121: J-band observations
  45. GRB 011121: NIR observations, host galaxy?
  46. GRB 011121: HST Scheduled
  47. GRB011121: fainter still
  48. Correction: GCN1157 (GRB 011121)
  49. GRB 011121: Radio Observations
  50. GRB 011121 J-Band Astrometry
  51. GRB011121: continued decay
  52. GRB 011121: Detection of Bright IR Counterpart
  53. GRB011121: possible redshift, continued decay
  54. IPN triangulation of GRB011121
  55. BEPPOSAX GRB011121
  56. GRB 011030: TNG K-band observation
  57. XRF011030: Chandra Observations
  58. GRB 011030: K-band observations
  59. GRB 011030 R band observations
  60. GRB 011030 I-band Observation
  61. The X-ray Flash 011030 ('GRB 011030')
  62. Non-triggered burst 011030 ("GRB 011030")
  63. The Radio Afterglow from the X-ray Rich GRB 011030
  64. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  65. GRB 970828: HST Observations of the Host Galaxy
  66. GRB 000131: HST Detection of the Host Galaxy
  67. GRB 970828: HST Observations of the Host Galaxy
  68. GRB010921, optical observation
  69. GRB 011019 optical observation
  70. GRB011019: Subaru Optical Observations
  71. GRB 011030 I-band Observations
  72. GRB 011030 K-band Observations
  73. GRB010921, optical observations
  74. GRB 011030, WSRT radio observations
  75. GRB011030 - further refinement WFC position
  76. GRB 011030, Radio observations
  77. GRB 011030, R-band observations
  78. BeppoSAX ALERT: Possible X-ray rich GRB011030
  79. GRB 010921: Possible supernova component
  80. GRB011019: NEAT Optical Observations
  81. GRB010921, optical observation at early time
  82. GRB 010921, I-band observations
  83. GRB011019: Optical observations
  84. GRB011019, optical observations
  85. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  86. GRB010921: Spectroscopy of the Host Galaxy
  87. GRB 010921: The afterglow of HETE #1761
  88. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  89. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  90. GRB010923 as seen by BeppoSAX GRBM
  91. GRB010928(=H1770): Localization of a Long GRB by HETE
  92. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  93. GRB010921, negative optical observations
  94. GRB010921 field photometry
  95. GRB010921 Optical Observations
  96. GRB 010921 DPOSS Images Available
  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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