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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').
  1. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  2. GRB021004: optical observations at Bisei
  3. GRB 021004: Kyoto observation
  4. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  5. GRB021004: Optical Afterglow
  6. XRF020903: TNG and Asiago photometry
  7. GRB 020903: Optical observations at RIKEN
  8. XRF 020903: Correction to GCN 1560
  9. XRF 020903: VRI observations
  10. IPN triangulation of GRB020926 (single large error box)
  11. GRB 020903: correction to GCN 1557
  12. XRF 020903: R band observations
  13. XRF 020903: Archival Optical Images
  14. Radio Observations of XRF 020903: The Missing Link
  15. XRF 020903: Supernova
  16. IPN triangulation of GRB020926 (two large error boxes)
  17. GRB020924 (ecliptic latitude-only localization)
  18. IPN triangulation of GRB020923 (two error boxes)
  19. IPN annulus for GRB020923
  20. IPN triangulation of GRB020914B
  21. Improved IPN position for GRB020918 (two large error boxes)
  22. IPN annulus for GRB020914B
  23. IPN triangulation of GRB020918 (annulus)
  24. IPN triangulation of GRB020911 (2 large error boxes)
  25. IPN triangulation of GRB020914 - clarification and additional information
  26. IPN triangulation of GRB020914
  27. GRB 020305: HST/STIS observations
  28. Confirmation of IPN error box for GRB020910
  29. IPN triangulation of GRB020910
  30. IPN GCN Circulars now to be issued without restriction
  31. Single IPN error box for GRB020904
  32. XRF 020903: optical observation at Kyoto
  33. GRB020322 : HST/STIS observations
  34. XRF 020903: Optical observations
  35. IPN triangulation of GRB020904
  36. XRF 020903: Optical observations
  37. IPN detection of a burst from SGR1900+14
  38. XRF 020903, optical observations
  39. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  40. INTEGRAL GRBs added to GCN
  41. GRB020813: optical observation
  42. GRB020812: optical observation
  43. GRB020819(=H2275): Revised Localization with HETE Soft X-ray
  44. SGR1900+14 burst localized by HETE
  45. GRB020813: High-resolution optical spectroscopy
  46. GRB020819: optical observations at Bisei
  47. GRB020812: negative optical observations
  48. GRB 020812: optical observation at Kyoto University
  49. Second epoch K band imaging of GRB 020819
  50. GRB020813, Baade 6.5m data now available
  51. GRB 020813 : HST observations
  52. Confirming no variability for GRB02081
  53. GRB020819 : Optical observations at KISO
  54. GRB 020812: early time optical observation at Ouda Station
  55. GRB020813: VRI Decay Slopes
  56. GRB020813: Magellan BVRI Photometry
  57. GRB 020819 : OT candidate - confirmation of non variability
  58. GRB 020819: Optical observations
  59. K band observation of GRB 020819
  60. GRB020819: optical observations
  61. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  62. IPN triangulation of GRB020819 (HETE 2275)
  63. HETE 2275: Optical observations
  64. GRB020813: optical and NIR observations
  65. GRB020813: Fading X-ray Afterglow Observed with Chandra
  66. GRB020813, UBVRI field calibration
  67. GRB 020813: addendum to GCN 1498
  68. GRB020813: optical observations at Bisei
  69. GRB020813: V-band decay slope
  70. GRB020812: NIR observations
  71. Polarimetry of GRB020813: evidence for variability
  72. GRB020813 IRAM millimeter observations
  73. GRB020812: optical observations
  74. GRB020813: High-Resolution Optical Observations
  75. GRB020813(=H2262): Revised Localization with HETE SXC
  76. GRB 020812: optical observation at Bisei
  77. GRB020813: Early Time Magnitude
  78. GRB020813: optical observations; possible host galaxy
  79. GRB 020813, radio detection
  80. GRB 020812 : optical afterglow candidate
  81. GRB020813, optical observations
  82. Millimeter observation of GRB 020813
  83. GRB020812: optical observations
  84. GRB 020813 : KISO multiband optical observations
  85. GRB020813, optical observations
  86. IPN error box for GRB020813
  87. IPN triangulation of GRB020813
  88. GRB020812: possible afterglow candidate
  89. Early Time Limits for GRB020813
  90. GRB020812: possible afterglow candidate
  91. GRB020813, astrometric position
  92. Spectropolarimetry of GRB 020813
  93. GRB 020813 Afterglow Observations; Possible break
  94. GRB 020813: Absorption redshift
  95. GRB 020813 multiband optical observations
  96. GRB020813: optical afterglow
  97. GRB020813: Fading of Candidate OT
  98. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  99. GRB020813: Candidate Optical Afterglow
  100. GRB 020812 optical observation

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