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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"

36149 results found.

  1. GRB 021004: optical counterpart
  2. GRB 021004, optical observations
  3. GRB021004: Optical Spectroscopy
  4. GRB 021004: Optical Observations
  5. GRB 021004, SPM optical observations
  6. GRB 021004, optical observations
  7. GRB 021004 radio search
  8. GRB 021004: radio observations
  9. GRB 021004: steepening of the optical decay slope
  10. GRB021004: Upper limits from recent and historical observations
  11. XRF020903, BVRI field photometry
  12. GRB021004: optical observations at Nyrola
  13. GRB021004: Absorption redshift
  14. GRB 021004: Kyoto observation
  15. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  16. GRB021004: Optical Afterglow
  17. GRB 020903: Optical observations at RIKEN
  18. IPN triangulation of GRB020926 (single large error box)
  19. GRB 020903: correction to GCN 1557
  20. XRF 020903: R band observations
  21. Radio Observations of XRF 020903: The Missing Link
  22. IPN triangulation of GRB020926 (two large error boxes)
  23. GRB020924 (ecliptic latitude-only localization)
  24. IPN triangulation of GRB020923 (two error boxes)
  25. IPN annulus for GRB020923
  26. IPN triangulation of GRB020914B
  27. Improved IPN position for GRB020918 (two large error boxes)
  28. IPN annulus for GRB020914B
  29. IPN triangulation of GRB020918 (annulus)
  30. IPN triangulation of GRB020911 (2 large error boxes)
  31. IPN triangulation of GRB020914 - clarification and additional information
  32. IPN triangulation of GRB020914
  33. GRB 020305: HST/STIS observations
  34. Confirmation of IPN error box for GRB020910
  35. IPN triangulation of GRB020910
  36. IPN GCN Circulars now to be issued without restriction
  37. Single IPN error box for GRB020904
  38. XRF 020903: optical observation at Kyoto
  39. GRB020322 : HST/STIS observations
  40. IPN triangulation of GRB020904
  41. IPN detection of a burst from SGR1900+14
  42. INTEGRAL GRBs added to GCN
  43. GRB020813: High-resolution optical spectroscopy
  44. GRB 020812: optical observation at Kyoto University
  45. Second epoch K band imaging of GRB 020819
  46. GRB020813, Baade 6.5m data now available
  47. GRB 020813 : HST observations
  48. Confirming no variability for GRB02081
  49. GRB020819 : Optical observations at KISO
  50. GRB 020812: early time optical observation at Ouda Station
  51. GRB020813: VRI Decay Slopes
  52. GRB 020819 : OT candidate - confirmation of non variability
  53. GRB 020819: Optical observations
  54. K band observation of GRB 020819
  55. GRB020819: optical observations
  56. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  57. IPN triangulation of GRB020819 (HETE 2275)
  58. GRB020813, UBVRI field calibration
  59. GRB 020813: addendum to GCN 1498
  60. GRB020813: optical observations at Bisei
  61. GRB020813: V-band decay slope
  62. Polarimetry of GRB020813: evidence for variability
  63. GRB020813 IRAM millimeter observations
  64. GRB020812: optical observations
  65. GRB 020812: optical observation at Bisei
  66. GRB020813: optical observations; possible host galaxy
  67. GRB 020813, radio detection
  68. GRB 020812 : optical afterglow candidate
  69. Millimeter observation of GRB 020813
  70. GRB020812: optical observations
  71. GRB 020813 : KISO multiband optical observations
  72. IPN error box for GRB020813
  73. IPN triangulation of GRB020813
  74. GRB020812: possible afterglow candidate
  75. Early Time Limits for GRB020813
  76. GRB020812: possible afterglow candidate
  77. GRB020813, astrometric position
  78. Spectropolarimetry of GRB 020813
  79. GRB 020813 Afterglow Observations; Possible break
  80. GRB 020813: Absorption redshift
  81. GRB 020813 multiband optical observations
  82. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  83. GRB 020812 optical observation
  84. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  85. GRB 020715, optical observations
  86. GRB 020714, optical observations
  87. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  88. HST Imaging of the Host of GRB 011121
  89. GRB020801, optical afterglow candidate
  90. Further refinement to IPN error box for GRB020531
  91. GRB020331: Late-time Optical Light Curve (re-submission)
  92. GRB020331: Late-time Optical Light Curve
  93. GRB 020405: HST observations reveal red bump
  94. IPN triangulation of GRB020714
  95. IPN triangulation of GRB020715 (=GRB150702)
  96. IPN triangulation of GRB020714
  97. IPN triangulation of GRB150702
  98. GRB 020410: Discovery of Probable OT by HST
  99. GRB 020124, HST observations of the fading afterglow
  100. IPN triangulation of GRB020708

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