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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"

35272 results found.

  1. GRB011019: NEAT Optical Observations
  2. GRB010921, optical observation at early time
  3. GRB 010921, I-band observations
  4. GRB011019: Optical observations
  5. GRB011019, optical observations
  6. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  7. GRB010921: Spectroscopy of the Host Galaxy
  8. GRB 010921: The afterglow of HETE #1761
  9. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  10. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  11. GRB010923 as seen by BeppoSAX GRBM
  12. GRB010928(=H1770): Localization of a Long GRB by HETE
  13. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  14. GRB010921, negative optical observations
  15. GRB010921 field photometry
  16. GRB010921 Optical Observations
  17. GRB 010921 DPOSS Images Available
  18. IPN triangulation of GRB010921 (=H1761)
  19. H1761: A Bright GRB Detected by HETE
  20. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  21. HETE Trigger #1760 (GRB 010920B?): a new optical source
  22. HETE Trigger #1759 (GRB 010920?) optical observations
  23. GRB001109, Host Galaxy Astrometry
  24. GRB000926, Host Galaxy Observations
  25. GRB001109, Host Galaxy Spectroscopic Observations
  26. Probable SGR or Short Duration GRB Detected by HETE
  27. GRB000926 Host Galaxy Observations
  28. GRB 010222: HST observations -- host galaxy and late-time decay
  29. BeppoSAX/GRBM detection of GRB 010801
  30. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  31. GRB 010222 - WHT BVRI images
  32. GRB 010629 Optical Observations
  33. GRB010629: Optical Observations
  34. GRB010629, optical observations
  35. IPN triangulation of GRB010629
  36. GRB010629: A Burst Localized by HETE
  37. Possible burst from SGR1806-20
  38. IPN detection of SGR1900+14
  39. GRB 00630: Host Galaxy
  40. IPN triangulation of GRB010613
  41. IPN triangulation of GRB010612
  42. HETE Fully-Automated GCN Notices
  43. GRB000301C: Late-time HST/STIS observation
  44. GRB010518: a faint BeppoSAX detection
  45. GRB000418: HST/STIS Second-epoch Observations
  46. GRB010427, Gamma Ray Observations
  47. SGR1900+14
  48. GRB 010222 /corrections to VBT data
  49. Possible precursor to the SGR1900+14 giant burst
  50. IPN Triangulation of the Giant Flare from SGR1900+14
  51. GRB010412, field photometry
  52. GRB 010326b Optical Observations
  53. GRB010412: Optical observations
  54. GRB010412: Optical observations
  55. IPN Triangulation of GRB010412
  56. BeppoSAX GRB: extension of BSAX operations upto April 30, 2002
  57. BeppoSAX GRB ALERT: GRB010412
  58. GRB Observation Report
  59. GRB010324, revised field photometry
  60. REVISED LOCATION OF GRB010326A
  61. GRB 980326: Late-time HST/STIS observations
  62. GRB010324, field photometry
  63. GRB010326B, field photometry
  64. GRB010326, field photometry
  65. GRB010220, field photometry
  66. Further Optical Observations of GRB 010324
  67. GRB 010326A: Further optical observations
  68. GRB010324: BeppoSAX/GRBM data
  69. GRB 010326B: Optical observations
  70. GRB010324, optical observations
  71. GRB010326B: Localization by HETE (2nd GRB for this date)
  72. GRB 010326: Optical observations
  73. GRB 010326 optical observations
  74. GRB010326: Refined Localization by HETE
  75. GRB010326: Localization by HETE
  76. Duration, ECT, peak flux and fluence of GRB010324
  77. Optical Observations of GRB 010324
  78. IPN TRIANGULATION OF GRB010324
  79. GRB990705, VLT-FORS1 observations of the host galaxy
  80. GRB010222, late-time optical observation
  81. Support extension to the BeppoSAX mission
  82. GRB 010222 - HEGRA GeV/TeV Observations
  83. Congratulate Scott on the 1000th GRB Coordinates Network Circular!
  84. GRB010222: Chandra X-ray Observatory Observation
  85. GRB010222: Sub-millimeter vanishing act
  86. GRB 010222, Optical Observations
  87. GRB 010222: High-Resolution Keck Spectroscopy
  88. GRB 010214, I-band data
  89. Sub-millimeter Excess/GRB 010222
  90. GRB 010222
  91. GRB 010222 HST/Chandra TOO
  92. GRB 010222
  93. GRB010222 further R-band photometry
  94. GRB010222: R-band data
  95. GRB010222 Optical observations
  96. GRB 010222: Keck Spectroscopy
  97. GRB010214, field photometry
  98. GRB010222, field photometry
  99. GRB010222 further R-band photometry
  100. GRB010222, possible increase of optical decay slope

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