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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. IPN triangulation of GRB021020
  2. GRB 021008, radio observations
  3. GRB 021016, optical observations
  4. GRB 021004: VRI observations at TNG: possible break
  5. GRB021016, optical observations
  6. SGR1900+14: burst on October 10 2002
  7. GRB 021008, optical observations
  8. GRB021016(=H2397): A Long GRB Localized by HETE
  9. IPN triangulation of GRB021016 (area corrected)
  10. IPN triangulation of GRB021016 (small error box)
  11. GRB021004: Optical Observations
  12. IPN triangulation of GRB021014 (large error box)
  13. IPN triangulation of GRB021013 (single error box)
  14. GRB 021004: optical spectroscopy on Oct 11
  15. IPN triangulation of GRB021013 (two small error boxes)
  16. GRB021004: High-resolution optical spectroscopy
  17. IPN triangulation of GRB021013 (annulus)
  18. XRF 020903: flattening of the optical light curve.
  19. GRB021004, UBVRcIc field photometry update
  20. IPN triangulation of GRB021008 (single error box)
  21. GRB021004: Optical Observations
  22. GRB 021004 submm observations
  23. IPN triangulation of GRB021008B (annulus)
  24. IPN triangulation of GRB021008 (two small error boxes)
  25. GRB021004 Chandra HETG Observations
  26. GRB 021004: Optical/NIR Observations
  27. GRB 021004: Additional V-band Polarimetric Observations
  28. GRB021004: optical observation
  29. GRB 021004: Host Galaxy Star Formation Rate
  30. GRB 021004 submm observations
  31. GRB 021004: WC wind?
  32. IPN triangulation of GRB021008
  33. GRB021004: NIR and Optical observations
  34. GRB 021004: Optical measurement at OHP
  35. GRB 021004: Optical observations, AUDE network
  36. GRB 021004 - VLA Radio Observations
  37. GRB 021004 - Unusual Radio-to-Submm Spectrum
  38. GRB 021004: optical spectroscopy
  39. IPN triangulation of GRB021007 (annulus)
  40. XRF 020903 spectrum
  41. GRB 021004: HST/STIS spectroscopic observations
  42. GRB021004: optical observations and predicted break time
  43. GRB021004: BVRc photometry
  44. GRB 021004 redshift
  45. GRB021004 radio observation
  46. GRB021004: restart of optical decay
  47. GRB 021004: Optical Decay
  48. GRB 021004 continued IR fading
  49. HETE fluences for GRB021004
  50. GRB 021004, spectroscopic observations
  51. GRB021004: not fading anymore?
  52. GRB 021004: Optical Photometry at 2.5 Days
  53. GRB 021004: polarimetric observations
  54. GRB 021004: V-band Polarimetric Observations
  55. GRB021004: Update Bisei photometric data
  56. GRB 021004: Optical Decay
  57. GRB021004, astrometric position
  58. GRB021004, Optical Observations
  59. IRAM Millimeter detection of GRB 021004
  60. GRB 021004: Optical observations at RIKEN
  61. GRB 021004 radio observation
  62. GRB 021004: Optical Observations
  63. GRB021004: continued fading
  64. GRB 021004: Optical Photometry at 1.5 Days
  65. GRB021004, Optical Observations
  66. GRB021004, BVRcIc field photometry
  67. GRB 021004: Optical observations
  68. GRB 021004: optical counterpart
  69. GRB 021004, optical observations
  70. GRB021004: Optical Spectroscopy
  71. GRB 021004: Optical Observations
  72. GRB 021004, SPM optical observations
  73. GRB 021004, optical observations
  74. GRB 021004 radio search
  75. GRB 021004: radio observations
  76. GRB 021004: steepening of the optical decay slope
  77. GRB021004: Upper limits from recent and historical observations
  78. XRF020903, BVRI field photometry
  79. GRB021004: optical observations at Nyrola
  80. GRB021004: Absorption redshift
  81. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  82. GRB021004: optical observations at Bisei
  83. GRB 021004: Kyoto observation
  84. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  85. GRB021004: Optical Afterglow
  86. XRF020903: TNG and Asiago photometry
  87. GRB 020903: Optical observations at RIKEN
  88. XRF 020903: Correction to GCN 1560
  89. XRF 020903: VRI observations
  90. IPN triangulation of GRB020926 (single large error box)
  91. GRB 020903: correction to GCN 1557
  92. XRF 020903: R band observations
  93. XRF 020903: Archival Optical Images
  94. Radio Observations of XRF 020903: The Missing Link
  95. XRF 020903: Supernova
  96. IPN triangulation of GRB020926 (two large error boxes)
  97. GRB020924 (ecliptic latitude-only localization)
  98. IPN triangulation of GRB020923 (two error boxes)
  99. IPN annulus for GRB020923
  100. IPN triangulation of GRB020914B

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