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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"

35957 results found.

  1. GRB 021004: Optical Decay
  2. GRB021004, astrometric position
  3. GRB021004, Optical Observations
  4. IRAM Millimeter detection of GRB 021004
  5. GRB 021004: Optical observations at RIKEN
  6. GRB 021004 radio observation
  7. GRB 021004: Optical Observations
  8. GRB021004: continued fading
  9. GRB 021004: Optical Photometry at 1.5 Days
  10. GRB021004, Optical Observations
  11. GRB021004, BVRcIc field photometry
  12. GRB 021004: Optical observations
  13. GRB 021004: optical counterpart
  14. GRB 021004, optical observations
  15. GRB021004: Optical Spectroscopy
  16. GRB 021004: Optical Observations
  17. GRB 021004, SPM optical observations
  18. GRB 021004, optical observations
  19. GRB 021004 radio search
  20. GRB 021004: radio observations
  21. GRB 021004: steepening of the optical decay slope
  22. GRB021004: Upper limits from recent and historical observations
  23. XRF020903, BVRI field photometry
  24. GRB021004: optical observations at Nyrola
  25. GRB021004: Absorption redshift
  26. GRB 021004: Kyoto observation
  27. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  28. GRB021004: Optical Afterglow
  29. GRB 020903: Optical observations at RIKEN
  30. IPN triangulation of GRB020926 (single large error box)
  31. GRB 020903: correction to GCN 1557
  32. XRF 020903: R band observations
  33. Radio Observations of XRF 020903: The Missing Link
  34. IPN triangulation of GRB020926 (two large error boxes)
  35. GRB020924 (ecliptic latitude-only localization)
  36. IPN triangulation of GRB020923 (two error boxes)
  37. IPN annulus for GRB020923
  38. IPN triangulation of GRB020914B
  39. Improved IPN position for GRB020918 (two large error boxes)
  40. IPN annulus for GRB020914B
  41. IPN triangulation of GRB020918 (annulus)
  42. IPN triangulation of GRB020911 (2 large error boxes)
  43. IPN triangulation of GRB020914 - clarification and additional information
  44. IPN triangulation of GRB020914
  45. GRB 020305: HST/STIS observations
  46. Confirmation of IPN error box for GRB020910
  47. IPN triangulation of GRB020910
  48. IPN GCN Circulars now to be issued without restriction
  49. Single IPN error box for GRB020904
  50. XRF 020903: optical observation at Kyoto
  51. GRB020322 : HST/STIS observations
  52. IPN triangulation of GRB020904
  53. IPN detection of a burst from SGR1900+14
  54. INTEGRAL GRBs added to GCN
  55. GRB020813: High-resolution optical spectroscopy
  56. GRB 020812: optical observation at Kyoto University
  57. Second epoch K band imaging of GRB 020819
  58. GRB020813, Baade 6.5m data now available
  59. GRB 020813 : HST observations
  60. Confirming no variability for GRB02081
  61. GRB020819 : Optical observations at KISO
  62. GRB 020812: early time optical observation at Ouda Station
  63. GRB020813: VRI Decay Slopes
  64. GRB 020819 : OT candidate - confirmation of non variability
  65. GRB 020819: Optical observations
  66. K band observation of GRB 020819
  67. GRB020819: optical observations
  68. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  69. IPN triangulation of GRB020819 (HETE 2275)
  70. GRB020813, UBVRI field calibration
  71. GRB 020813: addendum to GCN 1498
  72. GRB020813: optical observations at Bisei
  73. GRB020813: V-band decay slope
  74. Polarimetry of GRB020813: evidence for variability
  75. GRB020813 IRAM millimeter observations
  76. GRB020812: optical observations
  77. GRB 020812: optical observation at Bisei
  78. GRB020813: optical observations; possible host galaxy
  79. GRB 020813, radio detection
  80. GRB 020812 : optical afterglow candidate
  81. Millimeter observation of GRB 020813
  82. GRB020812: optical observations
  83. GRB 020813 : KISO multiband optical observations
  84. IPN error box for GRB020813
  85. IPN triangulation of GRB020813
  86. GRB020812: possible afterglow candidate
  87. Early Time Limits for GRB020813
  88. GRB020812: possible afterglow candidate
  89. GRB020813, astrometric position
  90. Spectropolarimetry of GRB 020813
  91. GRB 020813 Afterglow Observations; Possible break
  92. GRB 020813: Absorption redshift
  93. GRB 020813 multiband optical observations
  94. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  95. GRB 020812 optical observation
  96. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  97. GRB 020715, optical observations
  98. GRB 020714, optical observations
  99. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  100. HST Imaging of the Host of GRB 011121

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