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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"

37758 results found.

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

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