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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"

27399 results found.

  1. The Radio Afterglow from the X-ray Rich GRB 011030
  2. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  3. GRB 970828: HST Observations of the Host Galaxy
  4. GRB 000131: HST Detection of the Host Galaxy
  5. GRB 970828: HST Observations of the Host Galaxy
  6. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  7. GRB011019: Subaru Optical Observations
  8. GRB 011030 I-band Observations
  9. GRB 011030 K-band Observations
  10. GRB010921, optical observations
  11. GRB011030 - further refinement WFC position
  12. GRB 011030, Radio observations
  13. GRB011030: radio search
  14. GRB 010921: Possible supernova component
  15. GRB010921, optical observation at early time
  16. GRB 010921, I-band observations
  17. GRB011019, optical observations
  18. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  19. GRB 010921: The afterglow of HETE #1761
  20. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  21. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  22. GRB010923 as seen by BeppoSAX GRBM
  23. GRB010928(=H1770): Localization of a Long GRB by HETE
  24. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  25. GRB010921, negative optical observations
  26. GRB010921 field photometry
  27. H1761: A Bright GRB Detected by HETE
  28. GRB000926, Host Galaxy Observations
  29. GRB001109, Host Galaxy Spectroscopic Observations
  30. Probable SGR or Short Duration GRB Detected by HETE
  31. GCN and HETE status
  32. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  33. GRB 010222 - WHT BVRI images
  34. SGR1900+14 burst seen by HETE: BeppoSAX data
  35. GRB 010629 Optical Observations
  36. SGR1900+14: High Fluence Burst Localized by HETE
  37. GRB010629, optical observations
  38. GRB010629: A Burst Localized by HETE
  39. SGR1900+14: Second Burst Localized by HETE
  40. SGR1900+14: A Burst Localized by HETE
  41. SGR1806-20: A Second, Intense Burst Localized by HETE
  42. SGR1806-20: Localization by HETE
  43. HETE Fully-Automated GCN Notices
  44. GRB000301C: Late-time HST/STIS observation
  45. GRB010518: a faint BeppoSAX detection
  46. GRB000418: HST/STIS Second-epoch Observations
  47. X-ray precursors to the large flare from SGR 1900+14
  48. GRB010427, Gamma Ray Observations
  49. SGR 1900+14: No evidence of extended X-ray emission
  50. SGR 1900+14 : RXTE observations
  51. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  52. SGR 1900+14: Correction to GCN 1049
  53. GRB 010222 /corrections to VBT data
  54. Millimeter observation of SGR 1900+14
  55. SGR 1900+14: Detection of extended X-ray emission
  56. SGR 1900+14, Chandra observations
  57. SGR1900+14, I-band observations
  58. GRB010412, field photometry
  59. Giant flare from SGR1900+14
  60. GRB 010326b Optical Observations
  61. GRB010412: BeppoSAX GRBM and WFC observations
  62. GRB010324, revised field photometry
  63. REVISED LOCATION OF GRB010326A
  64. GRB 980326: Late-time HST/STIS observations
  65. GRB010324, field photometry
  66. GRB010326B, field photometry
  67. GRB010326, field photometry
  68. GRB010220, field photometry
  69. Further Optical Observations of GRB 010324
  70. GRB010222, CXO X-ray observations
  71. GRB010324, optical observations
  72. GRB010326B: Localization by HETE (2nd GRB for this date)
  73. GRB 010326 optical observations
  74. GRB010326: Refined Localization by HETE
  75. GRB010326: Localization by HETE
  76. Optical Observations of GRB 010324
  77. GRB010222, late-time optical observation
  78. Support extension to the BeppoSAX mission
  79. GRB 010222 - HEGRA GeV/TeV Observations
  80. GRB010222: Chandra X-ray Observatory Observation
  81. GRB010222: Sub-millimeter vanishing act
  82. GRB010222 - Optical observation
  83. GRB 010222, Optical Observations
  84. GRB010222 - Optical observation
  85. GRB 010222: High-Resolution Keck Spectroscopy
  86. GRB 010214, I-band data
  87. GRB 010222
  88. GRB010222 further R-band photometry
  89. GRB010222: R-band data
  90. GRB 010222: Keck Spectroscopy
  91. GRB010214, field photometry
  92. GRB010222, field photometry
  93. GRB010222 further R-band photometry
  94. GRB010222, possible increase of optical decay slope
  95. GRB 010222 Kyoto optical observation
  96. GRB010222 R-BAND OBSERVATION
  97. GRB010214 follow-up from Hanle
  98. GRB 010222: Near-IR Observations
  99. GRB 010222: Optical Observations
  100. GRB010222: Optical decay slope

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