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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"

26316 results found.

  1. XRF011130: Infrared Observations
  2. GRB 011121
  3. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  4. GRB 011121: J-band observations
  5. GRB 011121: NIR observations, host galaxy?
  6. GRB011121: UBRI Observations
  7. GRB 011121 J-Band Astrometry
  8. GRB 011121: Detection of Bright IR Counterpart
  9. GRB011121: possible redshift, continued decay
  10. GRB 011030: TNG K-band observation
  11. XRF011030: J and K band observations
  12. XRF011030: Chandra Observations
  13. GRB011030: Z-band observations
  14. GRB 011030 R band observations
  15. GRB 011030 I-band Observation
  16. The X-ray Flash 011030 ('GRB 011030')
  17. Non-triggered burst 011030 ("GRB 011030")
  18. The Radio Afterglow from the X-ray Rich GRB 011030
  19. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  20. GRB 970828: HST Observations of the Host Galaxy
  21. GRB 000131: HST Detection of the Host Galaxy
  22. GRB 970828: HST Observations of the Host Galaxy
  23. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  24. GRB011019: Subaru Optical Observations
  25. GRB 011030 I-band Observations
  26. GRB 011030 K-band Observations
  27. GRB010921, optical observations
  28. GRB011030 - further refinement WFC position
  29. GRB 011030, Radio observations
  30. GRB011030: radio search
  31. GRB 010921: Possible supernova component
  32. GRB010921, optical observation at early time
  33. GRB 010921, I-band observations
  34. GRB011019, optical observations
  35. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  36. GRB 010921: The afterglow of HETE #1761
  37. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  38. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  39. GRB010923 as seen by BeppoSAX GRBM
  40. GRB010928(=H1770): Localization of a Long GRB by HETE
  41. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  42. GRB010921, negative optical observations
  43. GRB010921 field photometry
  44. H1761: A Bright GRB Detected by HETE
  45. GRB000926, Host Galaxy Observations
  46. GRB001109, Host Galaxy Spectroscopic Observations
  47. Probable SGR or Short Duration GRB Detected by HETE
  48. GCN and HETE status
  49. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  50. GRB 010222 - WHT BVRI images
  51. SGR1900+14 burst seen by HETE: BeppoSAX data
  52. GRB 010629 Optical Observations
  53. SGR1900+14: High Fluence Burst Localized by HETE
  54. GRB010629, optical observations
  55. GRB010629: A Burst Localized by HETE
  56. SGR1900+14: Second Burst Localized by HETE
  57. SGR1900+14: A Burst Localized by HETE
  58. SGR1806-20: A Second, Intense Burst Localized by HETE
  59. SGR1806-20: Localization by HETE
  60. HETE Fully-Automated GCN Notices
  61. GRB000301C: Late-time HST/STIS observation
  62. GRB010518: a faint BeppoSAX detection
  63. GRB000418: HST/STIS Second-epoch Observations
  64. X-ray precursors to the large flare from SGR 1900+14
  65. GRB010427, Gamma Ray Observations
  66. SGR 1900+14: No evidence of extended X-ray emission
  67. SGR 1900+14 : RXTE observations
  68. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  69. SGR 1900+14: Correction to GCN 1049
  70. GRB 010222 /corrections to VBT data
  71. Millimeter observation of SGR 1900+14
  72. SGR 1900+14: Detection of extended X-ray emission
  73. SGR 1900+14, Chandra observations
  74. SGR1900+14, I-band observations
  75. GRB010412, field photometry
  76. Giant flare from SGR1900+14
  77. GRB 010326b Optical Observations
  78. GRB010412: BeppoSAX GRBM and WFC observations
  79. GRB010324, revised field photometry
  80. REVISED LOCATION OF GRB010326A
  81. GRB 980326: Late-time HST/STIS observations
  82. GRB010324, field photometry
  83. GRB010326B, field photometry
  84. GRB010326, field photometry
  85. GRB010220, field photometry
  86. Further Optical Observations of GRB 010324
  87. GRB010222, CXO X-ray observations
  88. GRB010324, optical observations
  89. GRB010326B: Localization by HETE (2nd GRB for this date)
  90. GRB 010326 optical observations
  91. GRB010326: Refined Localization by HETE
  92. GRB010326: Localization by HETE
  93. Optical Observations of GRB 010324
  94. GRB010222, late-time optical observation
  95. Support extension to the BeppoSAX mission
  96. GRB 010222 - HEGRA GeV/TeV Observations
  97. GRB010222: Chandra X-ray Observatory Observation
  98. GRB010222: Sub-millimeter vanishing act
  99. GRB010222 - Optical observation
  100. GRB 010222, Optical Observations

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