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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"

32501 results found.

  1. GRB 021004: Additional V-band Polarimetric Observations
  2. GRB021004: optical observation
  3. GRB 021004: Host Galaxy Star Formation Rate
  4. GRB 021004 submm observations
  5. GRB 021004: WC wind?
  6. GRB021004: NIR and Optical observations
  7. GRB 021004: Optical measurement at OHP
  8. GRB 021004: Optical observations, AUDE network
  9. GRB 021004 - VLA Radio Observations
  10. GRB 021004 - Unusual Radio-to-Submm Spectrum
  11. XRF 020903 spectrum
  12. GRB021004: optical observations and predicted break time
  13. GRB021004: BVRc photometry
  14. GRB 021004 redshift
  15. GRB021004: restart of optical decay
  16. GRB 021004: Optical Decay
  17. GRB 021004, spectroscopic observations
  18. GRB021004: not fading anymore?
  19. GRB 021004: Optical Photometry at 2.5 Days
  20. GRB 021004: polarimetric observations
  21. GRB 021004: V-band Polarimetric Observations
  22. GRB021004: Update Bisei photometric data
  23. GRB 021004: Optical Decay
  24. GRB021004, astrometric position
  25. GRB021004, Optical Observations
  26. IRAM Millimeter detection of GRB 021004
  27. GRB 021004: Optical observations at RIKEN
  28. GRB 021004 radio observation
  29. GRB 021004: Optical Observations
  30. GRB021004: continued fading
  31. GRB 021004: Optical Photometry at 1.5 Days
  32. GRB021004, Optical Observations
  33. GRB021004, BVRcIc field photometry
  34. GRB 021004: Optical observations
  35. GRB 021004: optical counterpart
  36. GRB 021004, optical observations
  37. GRB021004: Optical Spectroscopy
  38. GRB 021004: Optical Observations
  39. GRB 021004, SPM optical observations
  40. GRB 021004, optical observations
  41. GRB 021004 radio search
  42. GRB 021004: radio observations
  43. GRB 021004: steepening of the optical decay slope
  44. GRB021004: Upper limits from recent and historical observations
  45. XRF020903, BVRI field photometry
  46. GRB021004: optical observations at Nyrola
  47. GRB021004: Absorption redshift
  48. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  49. GRB021004: optical observations at Bisei
  50. GRB 021004: Kyoto observation
  51. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  52. XRF020903: TNG and Asiago photometry
  53. GRB 020903: Optical observations at RIKEN
  54. XRF 020903: Correction to GCN 1560
  55. XRF 020903: VRI observations
  56. IPN triangulation of GRB020926 (single large error box)
  57. GRB 020903: correction to GCN 1557
  58. XRF 020903: R band observations
  59. XRF 020903: Archival Optical Images
  60. Radio Observations of XRF 020903: The Missing Link
  61. XRF 020903: Supernova
  62. GRB020924 (ecliptic latitude-only localization)
  63. IPN triangulation of GRB020923 (two error boxes)
  64. IPN triangulation of GRB020914B
  65. Improved IPN position for GRB020918 (two large error boxes)
  66. IPN annulus for GRB020914B
  67. IPN triangulation of GRB020914 - clarification and additional information
  68. IPN triangulation of GRB020914
  69. GRB 020305: HST/STIS observations
  70. Confirmation of IPN error box for GRB020910
  71. IPN GCN Circulars now to be issued without restriction
  72. Single IPN error box for GRB020904
  73. XRF 020903: optical observation at Kyoto
  74. GRB020322 : HST/STIS observations
  75. XRF 020903: Optical observations
  76. IPN triangulation of GRB020904
  77. XRF 020903: Optical observations
  78. XRF 020903, optical observations
  79. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  80. INTEGRAL GRBs added to GCN
  81. GRB020813: optical observation
  82. GRB020812: optical observation
  83. GRB020819(=H2275): Revised Localization with HETE Soft X-ray
  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. GRB 020812: early time optical observation at Ouda Station
  93. GRB020813: VRI Decay Slopes
  94. GRB 020819 : OT candidate - confirmation of non variability
  95. GRB 020819: Optical observations
  96. K band observation of GRB 020819
  97. GRB020819: optical observations
  98. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  99. HETE 2275: Optical observations
  100. GRB020813: optical and NIR observations

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