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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"

32541 results found.

  1. GRB 011121: J-band observations
  2. GRB 011121: NIR observations, host galaxy?
  3. GRB010921 - Milagro GeV/TeV Observations
  4. GRB 011121: HST Scheduled
  5. GRB011121: fainter still
  6. Correction: GCN1157 (GRB 011121)
  7. GRB011121: UBRI Observations
  8. GRB011121
  9. GRB 011121: Radio Observations
  10. GRB 011121 J-Band Astrometry
  11. GRB011121: continued decay
  12. GRB 011121: Detection of Bright IR Counterpart
  13. GRB011121: possible redshift, continued decay
  14. GRB011121: fading behavior
  15. GRB011121: possible optical counterpart
  16. IPN triangulation of GRB011121
  17. GRB 011030: TNG K-band observation
  18. XRF011030: J and K band observations
  19. XRF011030: Chandra Observations
  20. GRB 011030: K-band observations
  21. GRB011030: Z-band observations
  22. GRB 011030 I-band Observation
  23. The X-ray Flash 011030 ('GRB 011030')
  24. The Radio Afterglow from the X-ray Rich GRB 011030
  25. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  26. GRB 000131: HST Detection of the Host Galaxy
  27. GRB 011019 optical observation
  28. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  29. GRB011019: Subaru Optical Observations
  30. GRB 011030 I-band Observations
  31. GRB 011030 K-band Observations
  32. GRB010921, optical observations
  33. GRB 011030, WSRT radio observations
  34. GRB011030 - further refinement WFC position
  35. GRB 011030, Radio observations
  36. GRB011030: radio search
  37. GRB 011030, R-band observations
  38. BeppoSAX ALERT: Possible X-ray rich GRB011030
  39. GRB 010921: Possible supernova component
  40. GRB011019: ROTSE-III optical observations
  41. GRB 010921, I-band observations
  42. GRB011019: Optical observations
  43. GRB011019, optical observations -- correction
  44. GRB011019, optical observations
  45. GRB010921: Spectroscopy of the Host Galaxy
  46. GRB 010921: The afterglow of HETE #1761
  47. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  48. GRB010923 as seen by BeppoSAX GRBM
  49. GRB010928(=H1770): Localization of a Long GRB by HETE
  50. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  51. GRB010921, negative optical observations
  52. GRB010921 field photometry
  53. GRB 010921 DPOSS Images Available
  54. IPN triangulation of GRB010921 (=H1761)
  55. H1761: A Bright GRB Detected by HETE
  56. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  57. GRB001109, Host Galaxy Astrometry
  58. GRB000926, Host Galaxy Observations
  59. GRB001109, Host Galaxy Spectroscopic Observations
  60. Probable SGR or Short Duration GRB Detected by HETE
  61. GCN and HETE status
  62. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  63. GRB 010222 - WHT BVRI images
  64. SGR1900+14 burst seen by HETE: BeppoSAX data
  65. GRB 010629 Optical Observations
  66. GRB010629: Optical Observations
  67. SGR1900+14: High Fluence Burst Localized by HETE
  68. GRB010629, optical observations
  69. IPN triangulation of GRB010629
  70. SGR1900+14: Second Burst Localized by HETE
  71. SGR1900+14: A Burst Localized by HETE
  72. Possible burst from SGR1806-20
  73. SGR1806-20: A Second, Intense Burst Localized by HETE
  74. IPN triangulation of GRB010613
  75. IPN triangulation of GRB010612
  76. IPN triangulation of GRB010612
  77. HETE Fully-Automated GCN Notices
  78. GRB000301C: Late-time HST/STIS observation
  79. GRB000418: HST/STIS Second-epoch Observations
  80. X-ray precursors to the large flare from SGR 1900+14
  81. GRB010214, optical observations
  82. SGR 1900+14: No evidence of extended X-ray emission
  83. SGR 1900+14 : RXTE observations
  84. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  85. SGR1900+14 - correction
  86. SGR1900+14
  87. SGR 1900+14: Correction to GCN 1049
  88. Millimeter observation of SGR 1900+14
  89. SGR 1900+14: Detection of extended X-ray emission
  90. Chandra Observations of SGR 1900+14
  91. SGR 1900+14, Chandra observations
  92. Chandra Observations of SGR 1900+14
  93. Possible precursor to the SGR1900+14 giant burst
  94. SGR1900+14, I-band observations
  95. IPN Triangulation of the Giant Flare from SGR1900+14
  96. GRB 010326b Optical Observations
  97. GRB010412: Optical observations
  98. GRB010412: Optical observations
  99. IPN Triangulation of GRB010412
  100. GRB Observation Report

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