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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"

32853 results found.

  1. GRB 021004: Optical Photometry at 1.5 Days
  2. GRB021004, Optical Observations
  3. GRB021004, BVRcIc field photometry
  4. GRB 021004: Optical observations
  5. GRB 021004: optical counterpart
  6. GRB 021004, optical observations
  7. GRB021004: Optical Spectroscopy
  8. GRB 021004: Optical Observations
  9. GRB 021004, SPM optical observations
  10. GRB 021004, optical observations
  11. GRB 021004 radio search
  12. GRB 021004: radio observations
  13. GRB 021004: steepening of the optical decay slope
  14. GRB021004: Upper limits from recent and historical observations
  15. XRF020903, BVRI field photometry
  16. GRB021004: optical observations at Nyrola
  17. GRB021004: Absorption redshift
  18. GRB 021004: Kyoto observation
  19. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  20. GRB021004: Optical Afterglow
  21. GRB 020903: Optical observations at RIKEN
  22. IPN triangulation of GRB020926 (single large error box)
  23. GRB 020903: correction to GCN 1557
  24. XRF 020903: R band observations
  25. Radio Observations of XRF 020903: The Missing Link
  26. IPN triangulation of GRB020926 (two large error boxes)
  27. GRB020924 (ecliptic latitude-only localization)
  28. IPN triangulation of GRB020923 (two error boxes)
  29. IPN annulus for GRB020923
  30. IPN triangulation of GRB020914B
  31. Improved IPN position for GRB020918 (two large error boxes)
  32. IPN annulus for GRB020914B
  33. IPN triangulation of GRB020918 (annulus)
  34. IPN triangulation of GRB020911 (2 large error boxes)
  35. IPN triangulation of GRB020914 - clarification and additional information
  36. IPN triangulation of GRB020914
  37. GRB 020305: HST/STIS observations
  38. Confirmation of IPN error box for GRB020910
  39. IPN triangulation of GRB020910
  40. IPN GCN Circulars now to be issued without restriction
  41. Single IPN error box for GRB020904
  42. XRF 020903: optical observation at Kyoto
  43. GRB020322 : HST/STIS observations
  44. IPN triangulation of GRB020904
  45. IPN detection of a burst from SGR1900+14
  46. INTEGRAL GRBs added to GCN
  47. GRB020813: High-resolution optical spectroscopy
  48. GRB 020812: optical observation at Kyoto University
  49. Second epoch K band imaging of GRB 020819
  50. GRB020813, Baade 6.5m data now available
  51. GRB 020813 : HST observations
  52. Confirming no variability for GRB02081
  53. GRB020819 : Optical observations at KISO
  54. GRB 020812: early time optical observation at Ouda Station
  55. GRB020813: VRI Decay Slopes
  56. GRB 020819 : OT candidate - confirmation of non variability
  57. GRB 020819: Optical observations
  58. K band observation of GRB 020819
  59. GRB020819: optical observations
  60. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  61. IPN triangulation of GRB020819 (HETE 2275)
  62. GRB020813, UBVRI field calibration
  63. GRB 020813: addendum to GCN 1498
  64. GRB020813: optical observations at Bisei
  65. GRB020813: V-band decay slope
  66. Polarimetry of GRB020813: evidence for variability
  67. GRB020813 IRAM millimeter observations
  68. GRB020812: optical observations
  69. GRB 020812: optical observation at Bisei
  70. GRB020813: optical observations; possible host galaxy
  71. GRB 020813, radio detection
  72. GRB 020812 : optical afterglow candidate
  73. Millimeter observation of GRB 020813
  74. GRB020812: optical observations
  75. GRB 020813 : KISO multiband optical observations
  76. IPN error box for GRB020813
  77. IPN triangulation of GRB020813
  78. GRB020812: possible afterglow candidate
  79. Early Time Limits for GRB020813
  80. GRB020812: possible afterglow candidate
  81. GRB020813, astrometric position
  82. Spectropolarimetry of GRB 020813
  83. GRB 020813 Afterglow Observations; Possible break
  84. GRB 020813: Absorption redshift
  85. GRB 020813 multiband optical observations
  86. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  87. GRB 020812 optical observation
  88. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  89. GRB 020715, optical observations
  90. GRB 020714, optical observations
  91. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  92. HST Imaging of the Host of GRB 011121
  93. GRB020801, optical afterglow candidate
  94. Further refinement to IPN error box for GRB020531
  95. GRB020331: Late-time Optical Light Curve (re-submission)
  96. GRB020331: Late-time Optical Light Curve
  97. GRB 020405: HST observations reveal red bump
  98. IPN triangulation of GRB020714
  99. IPN triangulation of GRB020715 (=GRB150702)
  100. IPN triangulation of GRB020714

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