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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"

44407 results found.

  1. GRB011030 - further refinement WFC position
  2. GRB 011030, Radio observations
  3. GRB011030: radio search
  4. GRB 011030, R-band observations
  5. X-ray rich GRB011030: BeppoSAX refined positions
  6. BeppoSAX ALERT: Possible X-ray rich GRB011030
  7. GRB 010921: Possible supernova component
  8. GRB011019: NEAT Optical Observations
  9. GRB011019: ROTSE-III optical observations
  10. GRB010921, optical observation at early time
  11. GRB 010921, I-band observations
  12. GRB011019: Optical observations
  13. GRB011019, optical observations
  14. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  15. GRB010921: Spectroscopy of the Host Galaxy
  16. GRB 010921: The afterglow of HETE #1761
  17. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  18. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  19. GRB010923 as seen by BeppoSAX GRBM
  20. GRB010928(=H1770): Localization of a Long GRB by HETE
  21. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  22. GRB010921, negative optical observations
  23. GRB010921 field photometry
  24. GRB010921 Optical Observations
  25. GRB 010921 DPOSS Images Available
  26. IPN triangulation of GRB010921 (=H1761)
  27. H1761: A Bright GRB Detected by HETE
  28. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  29. HETE Trigger #1760 (GRB 010920B?): a new optical source
  30. HETE Trigger #1759 (GRB 010920?) optical observations
  31. GRB001109, Host Galaxy Astrometry
  32. GRB000926, Host Galaxy Observations
  33. GRB001109, Host Galaxy Spectroscopic Observations
  34. Probable SGR or Short Duration GRB Detected by HETE
  35. GRB000926 Host Galaxy Observations
  36. GRB 010222: HST observations -- host galaxy and late-time decay
  37. BeppoSAX/GRBM detection of GRB 010801
  38. GCN and HETE status
  39. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  40. BeppoSAX/GRBM detection of GRB010728
  41. GRB 010222 - WHT BVRI images
  42. SGR1900+14 burst seen by HETE: BeppoSAX data
  43. GRB 010629 Optical Observations
  44. GRB010629: Optical Observations
  45. SGR1900+14: High Fluence Burst Localized by HETE
  46. GRB010629, optical observations
  47. IPN triangulation of GRB010629
  48. GRB010629: A Burst Localized by HETE
  49. SGR1900+14: Second Burst Localized by HETE
  50. SGR1900+14: A Burst Localized by HETE
  51. Possible burst from SGR1806-20
  52. IPN detection of SGR1900+14
  53. SGR1806-20: A Second, Intense Burst Localized by HETE
  54. GRB 00630: Host Galaxy
  55. SGR1806-20: Localization by HETE
  56. IPN triangulation of GRB010613
  57. IPN triangulation of GRB010612
  58. IPN triangulation of GRB010612
  59. HETE Fully-Automated GCN Notices
  60. GRB000301C: Late-time HST/STIS observation
  61. GRB010518: a faint BeppoSAX detection
  62. GRB000418: HST/STIS Second-epoch Observations
  63. X-ray precursors to the large flare from SGR 1900+14
  64. GRB010214, optical observations
  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. SGR1900+14
  70. SGR 1900+14: Correction to GCN 1049
  71. GRB 010222 /corrections to VBT data
  72. Millimeter observation of SGR 1900+14
  73. SGR 1900+14: Detection of extended X-ray emission
  74. Chandra Observations of SGR 1900+14
  75. SGR 1900+14, Chandra observations
  76. Chandra Observations of SGR 1900+14
  77. Possible precursor to the SGR1900+14 giant burst
  78. SGR1900+14, I-band observations
  79. IPN Triangulation of the Giant Flare from SGR1900+14
  80. GRB010412, field photometry
  81. Giant flare from SGR1900+14
  82. GRB 010326b Optical Observations
  83. GRB010412: Optical observations
  84. GRB010412: Optical observations
  85. GRB010412: BeppoSAX GRBM and WFC observations
  86. IPN Triangulation of GRB010412
  87. BeppoSAX GRB: extension of BSAX operations upto April 30, 2002
  88. BeppoSAX GRB ALERT: GRB010412
  89. GRB Observation Report
  90. GRB010324, revised field photometry
  91. REVISED LOCATION OF GRB010326A
  92. GRB 980326: Late-time HST/STIS observations
  93. GRB010324, field photometry
  94. GRB010326B, field photometry
  95. GRB010326, field photometry
  96. GRB010220, field photometry
  97. Further Optical Observations of GRB 010324
  98. GRB010222, CXO X-ray observations
  99. GRB 010326A: Further optical observations
  100. GRB010324: BeppoSAX/GRBM data

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