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

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