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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').
  1. XRF 020903: flattening of the optical light curve.
  2. GRB021004, UBVRcIc field photometry update
  3. IPN triangulation of GRB021008 (single error box)
  4. GRB021004: Optical Observations
  5. GRB 021004 submm observations
  6. IPN triangulation of GRB021008B (annulus)
  7. IPN triangulation of GRB021008 (two small error boxes)
  8. GRB021004 Chandra HETG Observations
  9. GRB 021004: Optical/NIR Observations
  10. GRB 021004: Additional V-band Polarimetric Observations
  11. GRB021004: optical observation
  12. GRB 021004: Host Galaxy Star Formation Rate
  13. GRB 021004 submm observations
  14. GRB 021004: WC wind?
  15. IPN triangulation of GRB021008
  16. GRB021004: NIR and Optical observations
  17. GRB 021004: Optical measurement at OHP
  18. GRB 021004: Optical observations, AUDE network
  19. GRB 021004 - VLA Radio Observations
  20. GRB 021004 - Unusual Radio-to-Submm Spectrum
  21. GRB 021004: optical spectroscopy
  22. IPN triangulation of GRB021007 (annulus)
  23. XRF 020903 spectrum
  24. GRB 021004: HST/STIS spectroscopic observations
  25. GRB021004: optical observations and predicted break time
  26. GRB021004: BVRc photometry
  27. GRB 021004 redshift
  28. GRB021004 radio observation
  29. GRB021004: restart of optical decay
  30. GRB 021004: Optical Decay
  31. GRB 021004 continued IR fading
  32. HETE fluences for GRB021004
  33. GRB 021004, spectroscopic observations
  34. GRB021004: not fading anymore?
  35. GRB 021004: Optical Photometry at 2.5 Days
  36. GRB 021004: polarimetric observations
  37. GRB 021004: V-band Polarimetric Observations
  38. GRB021004: Update Bisei photometric data
  39. GRB 021004: Optical Decay
  40. GRB021004, astrometric position
  41. GRB021004, Optical Observations
  42. IRAM Millimeter detection of GRB 021004
  43. GRB 021004: Optical observations at RIKEN
  44. GRB 021004 radio observation
  45. GRB 021004: Optical Observations
  46. GRB021004: continued fading
  47. GRB 021004: Optical Photometry at 1.5 Days
  48. GRB021004, Optical Observations
  49. GRB021004, BVRcIc field photometry
  50. GRB 021004: Optical observations
  51. GRB 021004: optical counterpart
  52. GRB 021004, optical observations
  53. GRB021004: Optical Spectroscopy
  54. GRB 021004: Optical Observations
  55. GRB 021004, SPM optical observations
  56. GRB 021004, optical observations
  57. GRB 021004 radio search
  58. GRB 021004: radio observations
  59. GRB 021004: steepening of the optical decay slope
  60. GRB021004: Upper limits from recent and historical observations
  61. XRF020903, BVRI field photometry
  62. GRB021004: optical observations at Nyrola
  63. GRB021004: Absorption redshift
  64. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  65. GRB021004: optical observations at Bisei
  66. GRB 021004: Kyoto observation
  67. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  68. GRB021004: Optical Afterglow
  69. XRF020903: TNG and Asiago photometry
  70. GRB 020903: Optical observations at RIKEN
  71. XRF 020903: Correction to GCN 1560
  72. XRF 020903: VRI observations
  73. IPN triangulation of GRB020926 (single large error box)
  74. GRB 020903: correction to GCN 1557
  75. XRF 020903: R band observations
  76. XRF 020903: Archival Optical Images
  77. Radio Observations of XRF 020903: The Missing Link
  78. XRF 020903: Supernova
  79. IPN triangulation of GRB020926 (two large error boxes)
  80. GRB020924 (ecliptic latitude-only localization)
  81. IPN triangulation of GRB020923 (two error boxes)
  82. IPN annulus for GRB020923
  83. IPN triangulation of GRB020914B
  84. Improved IPN position for GRB020918 (two large error boxes)
  85. IPN annulus for GRB020914B
  86. IPN triangulation of GRB020918 (annulus)
  87. IPN triangulation of GRB020911 (2 large error boxes)
  88. IPN triangulation of GRB020914 - clarification and additional information
  89. IPN triangulation of GRB020914
  90. GRB 020305: HST/STIS observations
  91. Confirmation of IPN error box for GRB020910
  92. IPN triangulation of GRB020910
  93. IPN GCN Circulars now to be issued without restriction
  94. Single IPN error box for GRB020904
  95. XRF 020903: optical observation at Kyoto
  96. GRB020322 : HST/STIS observations
  97. XRF 020903: Optical observations
  98. IPN triangulation of GRB020904
  99. XRF 020903: Optical observations
  100. IPN detection of a burst from SGR1900+14

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