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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"

24872 results found.

  1. GRB000926, Host Galaxy Observations
  2. GRB001109, Host Galaxy Spectroscopic Observations
  3. Probable SGR or Short Duration GRB Detected by HETE
  4. GCN and HETE status
  5. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  6. GRB 010222 - WHT BVRI images
  7. SGR1900+14 burst seen by HETE: BeppoSAX data
  8. GRB 010629 Optical Observations
  9. SGR1900+14: High Fluence Burst Localized by HETE
  10. GRB010629, optical observations
  11. GRB010629: A Burst Localized by HETE
  12. SGR1900+14: Second Burst Localized by HETE
  13. SGR1900+14: A Burst Localized by HETE
  14. SGR1806-20: A Second, Intense Burst Localized by HETE
  15. SGR1806-20: Localization by HETE
  16. HETE Fully-Automated GCN Notices
  17. GRB000301C: Late-time HST/STIS observation
  18. GRB010518: a faint BeppoSAX detection
  19. GRB000418: HST/STIS Second-epoch Observations
  20. X-ray precursors to the large flare from SGR 1900+14
  21. GRB010427, Gamma Ray Observations
  22. SGR 1900+14: No evidence of extended X-ray emission
  23. SGR 1900+14 : RXTE observations
  24. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  25. SGR 1900+14: Correction to GCN 1049
  26. GRB 010222 /corrections to VBT data
  27. Millimeter observation of SGR 1900+14
  28. SGR 1900+14: Detection of extended X-ray emission
  29. SGR 1900+14, Chandra observations
  30. SGR1900+14, I-band observations
  31. GRB010412, field photometry
  32. Giant flare from SGR1900+14
  33. GRB 010326b Optical Observations
  34. GRB010412: BeppoSAX GRBM and WFC observations
  35. GRB010324, revised field photometry
  36. REVISED LOCATION OF GRB010326A
  37. GRB 980326: Late-time HST/STIS observations
  38. GRB010324, field photometry
  39. GRB010326B, field photometry
  40. GRB010326, field photometry
  41. GRB010220, field photometry
  42. Further Optical Observations of GRB 010324
  43. GRB010222, CXO X-ray observations
  44. GRB010324, optical observations
  45. GRB010326B: Localization by HETE (2nd GRB for this date)
  46. GRB 010326 optical observations
  47. GRB010326: Refined Localization by HETE
  48. GRB010326: Localization by HETE
  49. Optical Observations of GRB 010324
  50. GRB010222, late-time optical observation
  51. Support extension to the BeppoSAX mission
  52. GRB 010222 - HEGRA GeV/TeV Observations
  53. GRB010222: Chandra X-ray Observatory Observation
  54. GRB010222: Sub-millimeter vanishing act
  55. GRB010222 - Optical observation
  56. GRB 010222, Optical Observations
  57. GRB010222 - Optical observation
  58. GRB 010222: High-Resolution Keck Spectroscopy
  59. GRB 010214, I-band data
  60. GRB 010222
  61. GRB010222 further R-band photometry
  62. GRB010222: R-band data
  63. GRB 010222: Keck Spectroscopy
  64. GRB010214, field photometry
  65. GRB010222, field photometry
  66. GRB010222 further R-band photometry
  67. GRB010222, possible increase of optical decay slope
  68. GRB 010222 Kyoto optical observation
  69. GRB010222 R-BAND OBSERVATION
  70. GRB010214 follow-up from Hanle
  71. GRB 010222: Near-IR Observations
  72. GRB 010222: Optical Observations
  73. GRB010222: Optical decay slope
  74. GRB 010214, Optical Observations
  75. GRB010222, radio observations
  76. GRB010222, optical observations
  77. GRB010222: BeppoSAX/NFI Observations
  78. GRB010214B,Gamma Ray Observations
  79. GRB 010220, simultaneous optical observations
  80. GRB010220: BeppoSAX WFC and GRBM preliminary data
  81. GRB010214, candidate optical afterglow
  82. GRB010214, optical observations
  83. GRB010214: BeppoSAX WFC and GRBM preliminary data
  84. GRB 010214: X-Ray afterglow
  85. GRB 010214 optical observation
  86. GRB010213, Radio Observations
  87. J-Band Observation of GRB 010214.
  88. GRB010213, Near-IR observations
  89. Possible InfraRed Transient of GRB 010214.
  90. GRB 010214, optical observations
  91. GRB010213 detected by HETE
  92. IPN Status Report
  93. HETE Status
  94. IPN/RXTE TRIANGULATION OF GRB010126
  95. GRB010126 Optical Observations
  96. IPN TRIANGULATION OF GRB010126
  97. Optical Observations of GRB 001018 at Keck
  98. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  99. Optical observations of GRB 001018 with JCAM
  100. IPN TRIANGULATION OF GRB010115

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