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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. GRB021016, optical observations
  2. SGR1900+14: burst on October 10 2002
  3. GRB 021008, optical observations
  4. GRB021016(=H2397): A Long GRB Localized by HETE
  5. IPN triangulation of GRB021016 (area corrected)
  6. IPN triangulation of GRB021016 (small error box)
  7. GRB021004: Optical Observations
  8. IPN triangulation of GRB021014 (large error box)
  9. IPN triangulation of GRB021013 (single error box)
  10. GRB 021004: optical spectroscopy on Oct 11
  11. IPN triangulation of GRB021013 (two small error boxes)
  12. GRB021004: High-resolution optical spectroscopy
  13. IPN triangulation of GRB021013 (annulus)
  14. XRF 020903: flattening of the optical light curve.
  15. GRB021004, UBVRcIc field photometry update
  16. IPN triangulation of GRB021008 (single error box)
  17. GRB021004: Optical Observations
  18. GRB 021004 submm observations
  19. IPN triangulation of GRB021008B (annulus)
  20. IPN triangulation of GRB021008 (two small error boxes)
  21. GRB021004 Chandra HETG Observations
  22. GRB 021004: Optical/NIR Observations
  23. GRB 021004: Additional V-band Polarimetric Observations
  24. GRB021004: optical observation
  25. GRB 021004: Host Galaxy Star Formation Rate
  26. GRB 021004 submm observations
  27. GRB 021004: WC wind?
  28. IPN triangulation of GRB021008
  29. GRB021004: NIR and Optical observations
  30. GRB 021004: Optical measurement at OHP
  31. GRB 021004: Optical observations, AUDE network
  32. GRB 021004 - VLA Radio Observations
  33. GRB 021004 - Unusual Radio-to-Submm Spectrum
  34. GRB 021004: optical spectroscopy
  35. IPN triangulation of GRB021007 (annulus)
  36. XRF 020903 spectrum
  37. GRB 021004: HST/STIS spectroscopic observations
  38. GRB021004: optical observations and predicted break time
  39. GRB021004: BVRc photometry
  40. GRB 021004 redshift
  41. GRB021004 radio observation
  42. GRB021004: restart of optical decay
  43. GRB 021004: Optical Decay
  44. GRB 021004 continued IR fading
  45. HETE fluences for GRB021004
  46. GRB 021004, spectroscopic observations
  47. GRB021004: not fading anymore?
  48. GRB 021004: Optical Photometry at 2.5 Days
  49. GRB 021004: polarimetric observations
  50. GRB 021004: V-band Polarimetric Observations
  51. GRB021004: Update Bisei photometric data
  52. GRB 021004: Optical Decay
  53. GRB021004, astrometric position
  54. GRB021004, Optical Observations
  55. IRAM Millimeter detection of GRB 021004
  56. GRB 021004: Optical observations at RIKEN
  57. GRB 021004 radio observation
  58. GRB 021004: Optical Observations
  59. GRB021004: continued fading
  60. GRB 021004: Optical Photometry at 1.5 Days
  61. GRB021004, Optical Observations
  62. GRB021004, BVRcIc field photometry
  63. GRB 021004: Optical observations
  64. GRB 021004: optical counterpart
  65. GRB 021004, optical observations
  66. GRB021004: Optical Spectroscopy
  67. GRB 021004: Optical Observations
  68. GRB 021004, SPM optical observations
  69. GRB 021004, optical observations
  70. GRB 021004 radio search
  71. GRB 021004: radio observations
  72. GRB 021004: steepening of the optical decay slope
  73. GRB021004: Upper limits from recent and historical observations
  74. XRF020903, BVRI field photometry
  75. GRB021004: optical observations at Nyrola
  76. GRB021004: Absorption redshift
  77. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  78. GRB021004: optical observations at Bisei
  79. GRB 021004: Kyoto observation
  80. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  81. GRB021004: Optical Afterglow
  82. XRF020903: TNG and Asiago photometry
  83. GRB 020903: Optical observations at RIKEN
  84. XRF 020903: Correction to GCN 1560
  85. XRF 020903: VRI observations
  86. IPN triangulation of GRB020926 (single large error box)
  87. GRB 020903: correction to GCN 1557
  88. XRF 020903: R band observations
  89. XRF 020903: Archival Optical Images
  90. Radio Observations of XRF 020903: The Missing Link
  91. XRF 020903: Supernova
  92. IPN triangulation of GRB020926 (two large error boxes)
  93. GRB020924 (ecliptic latitude-only localization)
  94. IPN triangulation of GRB020923 (two error boxes)
  95. IPN annulus for GRB020923
  96. IPN triangulation of GRB020914B
  97. Improved IPN position for GRB020918 (two large error boxes)
  98. IPN annulus for GRB020914B
  99. IPN triangulation of GRB020918 (annulus)
  100. IPN triangulation of GRB020911 (2 large error boxes)

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