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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"

32489 results found.

  1. GRB 010921 DPOSS Images Available
  2. IPN triangulation of GRB010921 (=H1761)
  3. H1761: A Bright GRB Detected by HETE
  4. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  5. GRB001109, Host Galaxy Astrometry
  6. GRB000926, Host Galaxy Observations
  7. GRB001109, Host Galaxy Spectroscopic Observations
  8. Probable SGR or Short Duration GRB Detected by HETE
  9. GCN and HETE status
  10. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  11. GRB 010222 - WHT BVRI images
  12. SGR1900+14 burst seen by HETE: BeppoSAX data
  13. GRB 010629 Optical Observations
  14. GRB010629: Optical Observations
  15. SGR1900+14: High Fluence Burst Localized by HETE
  16. GRB010629, optical observations
  17. IPN triangulation of GRB010629
  18. SGR1900+14: Second Burst Localized by HETE
  19. SGR1900+14: A Burst Localized by HETE
  20. Possible burst from SGR1806-20
  21. SGR1806-20: A Second, Intense Burst Localized by HETE
  22. IPN triangulation of GRB010613
  23. IPN triangulation of GRB010612
  24. IPN triangulation of GRB010612
  25. HETE Fully-Automated GCN Notices
  26. GRB000301C: Late-time HST/STIS observation
  27. GRB000418: HST/STIS Second-epoch Observations
  28. X-ray precursors to the large flare from SGR 1900+14
  29. GRB010214, optical observations
  30. SGR 1900+14: No evidence of extended X-ray emission
  31. SGR 1900+14 : RXTE observations
  32. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  33. SGR1900+14 - correction
  34. SGR1900+14
  35. SGR 1900+14: Correction to GCN 1049
  36. Millimeter observation of SGR 1900+14
  37. SGR 1900+14: Detection of extended X-ray emission
  38. Chandra Observations of SGR 1900+14
  39. SGR 1900+14, Chandra observations
  40. Chandra Observations of SGR 1900+14
  41. Possible precursor to the SGR1900+14 giant burst
  42. SGR1900+14, I-band observations
  43. IPN Triangulation of the Giant Flare from SGR1900+14
  44. GRB 010326b Optical Observations
  45. GRB010412: Optical observations
  46. GRB010412: Optical observations
  47. IPN Triangulation of GRB010412
  48. GRB Observation Report
  49. REVISED LOCATION OF GRB010326A
  50. GRB 980326: Late-time HST/STIS observations
  51. GRB010324, field photometry
  52. GRB010326B, field photometry
  53. GRB010326, field photometry
  54. GRB010220, field photometry
  55. Further Optical Observations of GRB 010324
  56. GRB010222, CXO X-ray observations
  57. GRB010324: BeppoSAX/GRBM data
  58. GRB010324, optical observations
  59. Duration, ECT, peak flux and fluence of GRB010324
  60. Optical Observations of GRB 010324
  61. IPN TRIANGULATION OF GRB010324
  62. GRB990705, VLT-FORS1 observations of the host galaxy
  63. GRB010222, late-time optical observation
  64. GRB 010222 - HEGRA GeV/TeV Observations
  65. Congratulate Scott on the 1000th GRB Coordinates Network Circular!
  66. GRB010222: Chandra X-ray Observatory Observation
  67. GRB010222: Sub-millimeter vanishing act
  68. GRB010222 - Optical observation
  69. GRB 010222, Optical Observations
  70. GRB010220 optical obsercations
  71. GRB010222 - Optical observation
  72. GRB 010222: High-Resolution Keck Spectroscopy
  73. GRB010222: Optical observation and decay
  74. GRB 010214, I-band data
  75. Sub-millimeter Excess/GRB 010222
  76. GRB 010222
  77. GRB 010222 HST/Chandra TOO
  78. GRB010222 further R-band photometry
  79. GRB010222: R-band data
  80. GRB010222 Optical observations
  81. GRB 010222: Keck Spectroscopy
  82. GRB010222 further R-band photometry
  83. GRB010222, possible increase of optical decay slope
  84. GRB010222: fading behavior
  85. GRB 010222 BV optical observations
  86. GRB010222 R-BAND OBSERVATION
  87. GRB 010220: Near-IR Observations
  88. GRB010214 follow-up from Hanle
  89. GRB 010222: Near-IR Observations
  90. GRB 010222: Optical Observations
  91. GRB 010222, Decay Slope Confirmed
  92. GRB010222: Another absorption line system
  93. GRB010222: Optical decay slope
  94. GRB 010214, Optical Observations
  95. GRB010222: Sub-millimeter detection
  96. GRB010222: R-band fading behavior
  97. GRB010222: Optical Observations
  98. GRB010222, radio observations
  99. GRB010222, optical observations
  100. GRB010222: BeppoSAX/NFI Observations

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