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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"

36155 results found.

  1. GRB 021004: Optical Observations
  2. GRB021004: continued fading
  3. GRB 021004: Optical Photometry at 1.5 Days
  4. GRB021004, Optical Observations
  5. GRB021004, BVRcIc field photometry
  6. GRB 021004: Optical observations
  7. GRB 021004: optical counterpart
  8. GRB 021004, optical observations
  9. GRB021004: Optical Spectroscopy
  10. GRB 021004: Optical Observations
  11. GRB 021004, SPM optical observations
  12. GRB 021004, optical observations
  13. GRB 021004 radio search
  14. GRB 021004: radio observations
  15. GRB 021004: steepening of the optical decay slope
  16. GRB021004: Upper limits from recent and historical observations
  17. XRF020903, BVRI field photometry
  18. GRB021004: optical observations at Nyrola
  19. GRB021004: Absorption redshift
  20. GRB 021004: Kyoto observation
  21. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  22. GRB021004: Optical Afterglow
  23. GRB 020903: Optical observations at RIKEN
  24. IPN triangulation of GRB020926 (single large error box)
  25. GRB 020903: correction to GCN 1557
  26. XRF 020903: R band observations
  27. Radio Observations of XRF 020903: The Missing Link
  28. IPN triangulation of GRB020926 (two large error boxes)
  29. GRB020924 (ecliptic latitude-only localization)
  30. IPN triangulation of GRB020923 (two error boxes)
  31. IPN annulus for GRB020923
  32. IPN triangulation of GRB020914B
  33. Improved IPN position for GRB020918 (two large error boxes)
  34. IPN annulus for GRB020914B
  35. IPN triangulation of GRB020918 (annulus)
  36. IPN triangulation of GRB020911 (2 large error boxes)
  37. IPN triangulation of GRB020914 - clarification and additional information
  38. IPN triangulation of GRB020914
  39. GRB 020305: HST/STIS observations
  40. Confirmation of IPN error box for GRB020910
  41. IPN triangulation of GRB020910
  42. IPN GCN Circulars now to be issued without restriction
  43. Single IPN error box for GRB020904
  44. XRF 020903: optical observation at Kyoto
  45. GRB020322 : HST/STIS observations
  46. IPN triangulation of GRB020904
  47. IPN detection of a burst from SGR1900+14
  48. INTEGRAL GRBs added to GCN
  49. GRB020813: High-resolution optical spectroscopy
  50. GRB 020812: optical observation at Kyoto University
  51. Second epoch K band imaging of GRB 020819
  52. GRB020813, Baade 6.5m data now available
  53. GRB 020813 : HST observations
  54. Confirming no variability for GRB02081
  55. GRB020819 : Optical observations at KISO
  56. GRB 020812: early time optical observation at Ouda Station
  57. GRB020813: VRI Decay Slopes
  58. GRB 020819 : OT candidate - confirmation of non variability
  59. GRB 020819: Optical observations
  60. K band observation of GRB 020819
  61. GRB020819: optical observations
  62. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  63. IPN triangulation of GRB020819 (HETE 2275)
  64. GRB020813, UBVRI field calibration
  65. GRB 020813: addendum to GCN 1498
  66. GRB020813: optical observations at Bisei
  67. GRB020813: V-band decay slope
  68. Polarimetry of GRB020813: evidence for variability
  69. GRB020813 IRAM millimeter observations
  70. GRB020812: optical observations
  71. GRB 020812: optical observation at Bisei
  72. GRB020813: optical observations; possible host galaxy
  73. GRB 020813, radio detection
  74. GRB 020812 : optical afterglow candidate
  75. Millimeter observation of GRB 020813
  76. GRB020812: optical observations
  77. GRB 020813 : KISO multiband optical observations
  78. IPN error box for GRB020813
  79. IPN triangulation of GRB020813
  80. GRB020812: possible afterglow candidate
  81. Early Time Limits for GRB020813
  82. GRB020812: possible afterglow candidate
  83. GRB020813, astrometric position
  84. Spectropolarimetry of GRB 020813
  85. GRB 020813 Afterglow Observations; Possible break
  86. GRB 020813: Absorption redshift
  87. GRB 020813 multiband optical observations
  88. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  89. GRB 020812 optical observation
  90. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  91. GRB 020715, optical observations
  92. GRB 020714, optical observations
  93. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  94. HST Imaging of the Host of GRB 011121
  95. GRB020801, optical afterglow candidate
  96. Further refinement to IPN error box for GRB020531
  97. GRB020331: Late-time Optical Light Curve (re-submission)
  98. GRB020331: Late-time Optical Light Curve
  99. GRB 020405: HST observations reveal red bump
  100. IPN triangulation of GRB020714

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