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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: Optical observations at RIKEN
  2. GRB 021004 radio observation
  3. GRB 021004: Optical Observations
  4. GRB021004: continued fading
  5. GRB 021004: Optical Photometry at 1.5 Days
  6. GRB021004, Optical Observations
  7. GRB021004, BVRcIc field photometry
  8. GRB 021004: Optical observations
  9. GRB 021004: optical counterpart
  10. GRB 021004, optical observations
  11. GRB021004: Optical Spectroscopy
  12. GRB 021004: Optical Observations
  13. GRB 021004, SPM optical observations
  14. GRB 021004, optical observations
  15. GRB 021004 radio search
  16. GRB 021004: radio observations
  17. GRB 021004: steepening of the optical decay slope
  18. GRB021004: Upper limits from recent and historical observations
  19. XRF020903, BVRI field photometry
  20. GRB021004: optical observations at Nyrola
  21. GRB021004: Absorption redshift
  22. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  23. GRB021004: optical observations at Bisei
  24. GRB 021004: Kyoto observation
  25. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  26. GRB021004: Optical Afterglow
  27. XRF020903: TNG and Asiago photometry
  28. GRB 020903: Optical observations at RIKEN
  29. XRF 020903: Correction to GCN 1560
  30. XRF 020903: VRI observations
  31. IPN triangulation of GRB020926 (single large error box)
  32. GRB 020903: correction to GCN 1557
  33. XRF 020903: R band observations
  34. XRF 020903: Archival Optical Images
  35. Radio Observations of XRF 020903: The Missing Link
  36. XRF 020903: Supernova
  37. IPN triangulation of GRB020926 (two large error boxes)
  38. GRB020924 (ecliptic latitude-only localization)
  39. IPN triangulation of GRB020923 (two error boxes)
  40. IPN annulus for GRB020923
  41. IPN triangulation of GRB020914B
  42. Improved IPN position for GRB020918 (two large error boxes)
  43. IPN annulus for GRB020914B
  44. IPN triangulation of GRB020918 (annulus)
  45. IPN triangulation of GRB020911 (2 large error boxes)
  46. IPN triangulation of GRB020914 - clarification and additional information
  47. IPN triangulation of GRB020914
  48. GRB 020305: HST/STIS observations
  49. Confirmation of IPN error box for GRB020910
  50. IPN triangulation of GRB020910
  51. IPN GCN Circulars now to be issued without restriction
  52. Single IPN error box for GRB020904
  53. XRF 020903: optical observation at Kyoto
  54. GRB020322 : HST/STIS observations
  55. XRF 020903: Optical observations
  56. IPN triangulation of GRB020904
  57. XRF 020903: Optical observations
  58. IPN detection of a burst from SGR1900+14
  59. XRF 020903, optical observations
  60. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  61. INTEGRAL GRBs added to GCN
  62. GRB020813: optical observation
  63. GRB020812: optical observation
  64. GRB020819(=H2275): Revised Localization with HETE Soft X-ray
  65. SGR1900+14 burst localized by HETE
  66. GRB020813: High-resolution optical spectroscopy
  67. GRB020819: optical observations at Bisei
  68. GRB020812: negative optical observations
  69. GRB 020812: optical observation at Kyoto University
  70. Second epoch K band imaging of GRB 020819
  71. GRB020813, Baade 6.5m data now available
  72. GRB 020813 : HST observations
  73. Confirming no variability for GRB02081
  74. GRB020819 : Optical observations at KISO
  75. GRB 020812: early time optical observation at Ouda Station
  76. GRB020813: VRI Decay Slopes
  77. GRB020813: Magellan BVRI Photometry
  78. GRB 020819 : OT candidate - confirmation of non variability
  79. GRB 020819: Optical observations
  80. K band observation of GRB 020819
  81. GRB020819: optical observations
  82. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  83. IPN triangulation of GRB020819 (HETE 2275)
  84. HETE 2275: Optical observations
  85. GRB020813: optical and NIR observations
  86. GRB020813: Fading X-ray Afterglow Observed with Chandra
  87. GRB020813, UBVRI field calibration
  88. GRB 020813: addendum to GCN 1498
  89. GRB020813: optical observations at Bisei
  90. GRB020813: V-band decay slope
  91. GRB020812: NIR observations
  92. Polarimetry of GRB020813: evidence for variability
  93. GRB020813 IRAM millimeter observations
  94. GRB020812: optical observations
  95. GRB020813: High-Resolution Optical Observations
  96. GRB020813(=H2262): Revised Localization with HETE SXC
  97. GRB 020812: optical observation at Bisei
  98. GRB020813: Early Time Magnitude
  99. GRB020813: optical observations; possible host galaxy
  100. GRB 020813, radio detection

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