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

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