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

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