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

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