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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"
  1. GRB011130, Radio Observations
  2. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  3. GRB011130 (=XRF011130), Optical Observations
  4. XRF011130: NEAT Optical Observations
  5. GRB011130 (=XRF011130): Revised Localization of an X-ray
  6. GRB001109, Radio Monitoring
  7. GRB 011121: Errata URL
  8. GRB 011121
  9. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  10. GRB 011121: J-band observations
  11. GRB 011121: NIR observations, host galaxy?
  12. GRB010921 - Milagro GeV/TeV Observations
  13. GRB 011121: HST Scheduled
  14. GRB011121: fainter still
  15. Correction: GCN1157 (GRB 011121)
  16. GRB011121: UBRI Observations
  17. GRB011121
  18. GRB 011121: Radio Observations
  19. GRB 011121 J-Band Astrometry
  20. GRB011121: continued decay
  21. GRB 011121: Detection of Bright IR Counterpart
  22. GRB011121: possible redshift, continued decay
  23. GRB011121: fading behavior
  24. GRB011121: possible optical counterpart
  25. GRB011121: BeppoSAX-WFC refined positions
  26. IPN triangulation of GRB011121
  27. BEPPOSAX GRB011121
  28. GRB 011030: TNG K-band observation
  29. XRF011030: J and K band observations
  30. GRB011030, optical observation
  31. XRF011030: Chandra Observations
  32. GRB 011030: K-band observations
  33. GRB011030: Z-band observations
  34. GRB 011030 R band observations
  35. GRB 011030 I-band Observation
  36. The X-ray Flash 011030 ('GRB 011030')
  37. Non-triggered burst 011030 ("GRB 011030")
  38. The Radio Afterglow from the X-ray Rich GRB 011030
  39. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  40. GRB 970828: HST Observations of the Host Galaxy
  41. GRB 000131: HST Detection of the Host Galaxy
  42. GRB 970828: HST Observations of the Host Galaxy
  43. GRB010921, optical observation
  44. GRB 011019 optical observation
  45. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  46. GRB011019: Subaru Optical Observations
  47. GRB 011030 I-band Observations
  48. GRB 011030 K-band Observations
  49. GRB010921, optical observations
  50. GRB 011030, WSRT radio observations
  51. GRB011030 - further refinement WFC position
  52. GRB 011030, Radio observations
  53. GRB011030: radio search
  54. GRB 011030, R-band observations
  55. X-ray rich GRB011030: BeppoSAX refined positions
  56. BeppoSAX ALERT: Possible X-ray rich GRB011030
  57. GRB 010921: Possible supernova component
  58. GRB011019: NEAT Optical Observations
  59. GRB011019: ROTSE-III optical observations
  60. GRB010921, optical observation at early time
  61. GRB 010921, I-band observations
  62. GRB011019: Optical observations
  63. GRB011019, optical observations -- correction
  64. GRB011019, optical observations
  65. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  66. GRB010921: Spectroscopy of the Host Galaxy
  67. GRB 010921: The afterglow of HETE #1761
  68. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  69. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  70. GRB010923 as seen by BeppoSAX GRBM
  71. GRB010928(=H1770): Localization of a Long GRB by HETE
  72. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  73. GRB010921, negative optical observations
  74. GRB010921 field photometry
  75. GRB010921 Optical Observations
  76. GRB 010921 DPOSS Images Available
  77. IPN triangulation of GRB010921 (=H1761)
  78. H1761: A Bright GRB Detected by HETE
  79. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  80. HETE Trigger #1760 (GRB 010920B?): a new optical source
  81. HETE Trigger #1759 (GRB 010920?) optical observations
  82. GRB001109, Host Galaxy Astrometry
  83. GRB000926, Host Galaxy Observations
  84. GRB001109, Host Galaxy Spectroscopic Observations
  85. Probable SGR or Short Duration GRB Detected by HETE
  86. GRB000926 Host Galaxy Observations
  87. GRB 010222: HST observations -- host galaxy and late-time decay
  88. BeppoSAX/GRBM detection of GRB 010801
  89. GCN and HETE status
  90. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  91. BeppoSAX/GRBM detection of GRB010728
  92. GRB 010222 - WHT BVRI images
  93. SGR1900+14 burst seen by HETE: BeppoSAX data
  94. GRB 010629 Optical Observations
  95. GRB010629: Optical Observations
  96. SGR1900+14: High Fluence Burst Localized by HETE
  97. GRB010629, optical observations
  98. IPN triangulation of GRB010629
  99. GRB010629: A Burst Localized by HETE
  100. SGR1900+14: Second Burst Localized by HETE

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