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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"

32537 results found.

  1. GRB011121: fainter still
  2. Correction: GCN1157 (GRB 011121)
  3. GRB011121: UBRI Observations
  4. GRB011121
  5. GRB 011121: Radio Observations
  6. GRB 011121 J-Band Astrometry
  7. GRB011121: continued decay
  8. GRB 011121: Detection of Bright IR Counterpart
  9. GRB011121: possible redshift, continued decay
  10. GRB011121: fading behavior
  11. GRB011121: possible optical counterpart
  12. IPN triangulation of GRB011121
  13. GRB 011030: TNG K-band observation
  14. XRF011030: J and K band observations
  15. XRF011030: Chandra Observations
  16. GRB 011030: K-band observations
  17. GRB011030: Z-band observations
  18. GRB 011030 I-band Observation
  19. The X-ray Flash 011030 ('GRB 011030')
  20. The Radio Afterglow from the X-ray Rich GRB 011030
  21. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  22. GRB 000131: HST Detection of the Host Galaxy
  23. GRB 011019 optical observation
  24. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  25. GRB011019: Subaru Optical Observations
  26. GRB 011030 I-band Observations
  27. GRB 011030 K-band Observations
  28. GRB010921, optical observations
  29. GRB 011030, WSRT radio observations
  30. GRB011030 - further refinement WFC position
  31. GRB 011030, Radio observations
  32. GRB011030: radio search
  33. GRB 011030, R-band observations
  34. BeppoSAX ALERT: Possible X-ray rich GRB011030
  35. GRB 010921: Possible supernova component
  36. GRB011019: ROTSE-III optical observations
  37. GRB 010921, I-band observations
  38. GRB011019: Optical observations
  39. GRB011019, optical observations -- correction
  40. GRB011019, optical observations
  41. GRB010921: Spectroscopy of the Host Galaxy
  42. GRB 010921: The afterglow of HETE #1761
  43. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  44. GRB010923 as seen by BeppoSAX GRBM
  45. GRB010928(=H1770): Localization of a Long GRB by HETE
  46. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  47. GRB010921, negative optical observations
  48. GRB010921 field photometry
  49. GRB 010921 DPOSS Images Available
  50. IPN triangulation of GRB010921 (=H1761)
  51. H1761: A Bright GRB Detected by HETE
  52. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  53. GRB001109, Host Galaxy Astrometry
  54. GRB000926, Host Galaxy Observations
  55. GRB001109, Host Galaxy Spectroscopic Observations
  56. Probable SGR or Short Duration GRB Detected by HETE
  57. GCN and HETE status
  58. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  59. GRB 010222 - WHT BVRI images
  60. SGR1900+14 burst seen by HETE: BeppoSAX data
  61. GRB 010629 Optical Observations
  62. GRB010629: Optical Observations
  63. SGR1900+14: High Fluence Burst Localized by HETE
  64. GRB010629, optical observations
  65. IPN triangulation of GRB010629
  66. SGR1900+14: Second Burst Localized by HETE
  67. SGR1900+14: A Burst Localized by HETE
  68. Possible burst from SGR1806-20
  69. SGR1806-20: A Second, Intense Burst Localized by HETE
  70. IPN triangulation of GRB010613
  71. IPN triangulation of GRB010612
  72. IPN triangulation of GRB010612
  73. HETE Fully-Automated GCN Notices
  74. GRB000301C: Late-time HST/STIS observation
  75. GRB000418: HST/STIS Second-epoch Observations
  76. X-ray precursors to the large flare from SGR 1900+14
  77. GRB010214, optical observations
  78. SGR 1900+14: No evidence of extended X-ray emission
  79. SGR 1900+14 : RXTE observations
  80. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  81. SGR1900+14 - correction
  82. SGR1900+14
  83. SGR 1900+14: Correction to GCN 1049
  84. Millimeter observation of SGR 1900+14
  85. SGR 1900+14: Detection of extended X-ray emission
  86. Chandra Observations of SGR 1900+14
  87. SGR 1900+14, Chandra observations
  88. Chandra Observations of SGR 1900+14
  89. Possible precursor to the SGR1900+14 giant burst
  90. SGR1900+14, I-band observations
  91. IPN Triangulation of the Giant Flare from SGR1900+14
  92. GRB 010326b Optical Observations
  93. GRB010412: Optical observations
  94. GRB010412: Optical observations
  95. IPN Triangulation of GRB010412
  96. GRB Observation Report
  97. REVISED LOCATION OF GRB010326A
  98. GRB 980326: Late-time HST/STIS observations
  99. GRB010324, field photometry
  100. GRB010326B, field photometry

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