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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"

35255 results found.

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

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