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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: optical observations and predicted break time
  2. GRB021004: BVRc photometry
  3. GRB 021004 redshift
  4. GRB021004 radio observation
  5. GRB021004: restart of optical decay
  6. GRB 021004: Optical Decay
  7. GRB 021004 continued IR fading
  8. HETE fluences for GRB021004
  9. GRB 021004, spectroscopic observations
  10. GRB021004: not fading anymore?
  11. GRB 021004: Optical Photometry at 2.5 Days
  12. GRB 021004: polarimetric observations
  13. GRB 021004: V-band Polarimetric Observations
  14. GRB021004: Update Bisei photometric data
  15. GRB 021004: Optical Decay
  16. GRB021004, astrometric position
  17. GRB021004, Optical Observations
  18. IRAM Millimeter detection of GRB 021004
  19. GRB 021004: Optical observations at RIKEN
  20. GRB 021004 radio observation
  21. GRB 021004: Optical Observations
  22. GRB021004: continued fading
  23. GRB 021004: Optical Photometry at 1.5 Days
  24. GRB021004, Optical Observations
  25. GRB021004, BVRcIc field photometry
  26. GRB 021004: Optical observations
  27. GRB 021004: optical counterpart
  28. GRB 021004, optical observations
  29. GRB021004: Optical Spectroscopy
  30. GRB 021004: Optical Observations
  31. GRB 021004, SPM optical observations
  32. GRB 021004, optical observations
  33. GRB 021004 radio search
  34. GRB 021004: radio observations
  35. GRB 021004: steepening of the optical decay slope
  36. GRB021004: Upper limits from recent and historical observations
  37. XRF020903, BVRI field photometry
  38. GRB021004: optical observations at Nyrola
  39. GRB021004: Absorption redshift
  40. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  41. GRB021004: optical observations at Bisei
  42. GRB 021004: Kyoto observation
  43. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  44. GRB021004: Optical Afterglow
  45. XRF020903: TNG and Asiago photometry
  46. GRB 020903: Optical observations at RIKEN
  47. XRF 020903: Correction to GCN 1560
  48. XRF 020903: VRI observations
  49. IPN triangulation of GRB020926 (single large error box)
  50. GRB 020903: correction to GCN 1557
  51. XRF 020903: R band observations
  52. XRF 020903: Archival Optical Images
  53. Radio Observations of XRF 020903: The Missing Link
  54. XRF 020903: Supernova
  55. IPN triangulation of GRB020926 (two large error boxes)
  56. GRB020924 (ecliptic latitude-only localization)
  57. IPN triangulation of GRB020923 (two error boxes)
  58. IPN annulus for GRB020923
  59. IPN triangulation of GRB020914B
  60. Improved IPN position for GRB020918 (two large error boxes)
  61. IPN annulus for GRB020914B
  62. IPN triangulation of GRB020918 (annulus)
  63. IPN triangulation of GRB020911 (2 large error boxes)
  64. IPN triangulation of GRB020914 - clarification and additional information
  65. IPN triangulation of GRB020914
  66. GRB 020305: HST/STIS observations
  67. Confirmation of IPN error box for GRB020910
  68. IPN triangulation of GRB020910
  69. IPN GCN Circulars now to be issued without restriction
  70. Single IPN error box for GRB020904
  71. XRF 020903: optical observation at Kyoto
  72. GRB020322 : HST/STIS observations
  73. XRF 020903: Optical observations
  74. IPN triangulation of GRB020904
  75. XRF 020903: Optical observations
  76. IPN detection of a burst from SGR1900+14
  77. XRF 020903, optical observations
  78. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  79. INTEGRAL GRBs added to GCN
  80. GRB020813: optical observation
  81. GRB020812: optical observation
  82. GRB020819(=H2275): Revised Localization with HETE Soft X-ray
  83. SGR1900+14 burst localized by HETE
  84. GRB020813: High-resolution optical spectroscopy
  85. GRB020819: optical observations at Bisei
  86. GRB020812: negative optical observations
  87. GRB 020812: optical observation at Kyoto University
  88. Second epoch K band imaging of GRB 020819
  89. GRB020813, Baade 6.5m data now available
  90. GRB 020813 : HST observations
  91. Confirming no variability for GRB02081
  92. GRB020819 : Optical observations at KISO
  93. GRB 020812: early time optical observation at Ouda Station
  94. GRB020813: VRI Decay Slopes
  95. GRB020813: Magellan BVRI Photometry
  96. GRB 020819 : OT candidate - confirmation of non variability
  97. GRB 020819: Optical observations
  98. K band observation of GRB 020819
  99. GRB020819: optical observations
  100. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC

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