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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"

32508 results found.

  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 GRB021008 (two small error boxes)
  7. GRB 021004: Optical/NIR Observations
  8. GRB 021004: Additional V-band Polarimetric Observations
  9. GRB021004: optical observation
  10. GRB 021004: Host Galaxy Star Formation Rate
  11. GRB 021004 submm observations
  12. GRB 021004: WC wind?
  13. GRB021004: NIR and Optical observations
  14. GRB 021004: Optical measurement at OHP
  15. GRB 021004: Optical observations, AUDE network
  16. GRB 021004 - VLA Radio Observations
  17. GRB 021004 - Unusual Radio-to-Submm Spectrum
  18. XRF 020903 spectrum
  19. GRB021004: optical observations and predicted break time
  20. GRB021004: BVRc photometry
  21. GRB 021004 redshift
  22. GRB021004: restart of optical decay
  23. GRB 021004: Optical Decay
  24. GRB 021004, spectroscopic observations
  25. GRB021004: not fading anymore?
  26. GRB 021004: Optical Photometry at 2.5 Days
  27. GRB 021004: polarimetric observations
  28. GRB 021004: V-band Polarimetric Observations
  29. GRB021004: Update Bisei photometric data
  30. GRB 021004: Optical Decay
  31. GRB021004, astrometric position
  32. GRB021004, Optical Observations
  33. IRAM Millimeter detection of GRB 021004
  34. GRB 021004: Optical observations at RIKEN
  35. GRB 021004 radio observation
  36. GRB 021004: Optical Observations
  37. GRB021004: continued fading
  38. GRB 021004: Optical Photometry at 1.5 Days
  39. GRB021004, Optical Observations
  40. GRB021004, BVRcIc field photometry
  41. GRB 021004: Optical observations
  42. GRB 021004: optical counterpart
  43. GRB 021004, optical observations
  44. GRB021004: Optical Spectroscopy
  45. GRB 021004: Optical Observations
  46. GRB 021004, SPM optical observations
  47. GRB 021004, optical observations
  48. GRB 021004 radio search
  49. GRB 021004: radio observations
  50. GRB 021004: steepening of the optical decay slope
  51. GRB021004: Upper limits from recent and historical observations
  52. XRF020903, BVRI field photometry
  53. GRB021004: optical observations at Nyrola
  54. GRB021004: Absorption redshift
  55. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  56. GRB021004: optical observations at Bisei
  57. GRB 021004: Kyoto observation
  58. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  59. XRF020903: TNG and Asiago photometry
  60. GRB 020903: Optical observations at RIKEN
  61. XRF 020903: Correction to GCN 1560
  62. XRF 020903: VRI observations
  63. IPN triangulation of GRB020926 (single large error box)
  64. GRB 020903: correction to GCN 1557
  65. XRF 020903: R band observations
  66. XRF 020903: Archival Optical Images
  67. Radio Observations of XRF 020903: The Missing Link
  68. XRF 020903: Supernova
  69. GRB020924 (ecliptic latitude-only localization)
  70. IPN triangulation of GRB020923 (two error boxes)
  71. IPN triangulation of GRB020914B
  72. Improved IPN position for GRB020918 (two large error boxes)
  73. IPN annulus for GRB020914B
  74. IPN triangulation of GRB020914 - clarification and additional information
  75. IPN triangulation of GRB020914
  76. GRB 020305: HST/STIS observations
  77. Confirmation of IPN error box for GRB020910
  78. IPN GCN Circulars now to be issued without restriction
  79. Single IPN error box for GRB020904
  80. XRF 020903: optical observation at Kyoto
  81. GRB020322 : HST/STIS observations
  82. XRF 020903: Optical observations
  83. IPN triangulation of GRB020904
  84. XRF 020903: Optical observations
  85. XRF 020903, optical observations
  86. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  87. INTEGRAL GRBs added to GCN
  88. GRB020813: optical observation
  89. GRB020812: optical observation
  90. GRB020819(=H2275): Revised Localization with HETE Soft X-ray
  91. GRB020813: High-resolution optical spectroscopy
  92. GRB020819: optical observations at Bisei
  93. GRB020812: negative optical observations
  94. GRB 020812: optical observation at Kyoto University
  95. Second epoch K band imaging of GRB 020819
  96. GRB020813, Baade 6.5m data now available
  97. GRB 020813 : HST observations
  98. Confirming no variability for GRB02081
  99. GRB 020812: early time optical observation at Ouda Station
  100. GRB020813: VRI Decay Slopes

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