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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"
  1. GRB020813: High-resolution optical spectroscopy
  2. GRB020819: optical observations at Bisei
  3. GRB020812: negative optical observations
  4. GRB 020812: optical observation at Kyoto University
  5. Second epoch K band imaging of GRB 020819
  6. GRB020813, Baade 6.5m data now available
  7. GRB 020813 : HST observations
  8. Confirming no variability for GRB02081
  9. GRB020819 : Optical observations at KISO
  10. GRB 020812: early time optical observation at Ouda Station
  11. GRB020813: VRI Decay Slopes
  12. GRB020813: Magellan BVRI Photometry
  13. GRB 020819 : OT candidate - confirmation of non variability
  14. GRB 020819: Optical observations
  15. K band observation of GRB 020819
  16. GRB020819: optical observations
  17. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  18. IPN triangulation of GRB020819 (HETE 2275)
  19. HETE 2275: Optical observations
  20. GRB020813: optical and NIR observations
  21. GRB020813: Fading X-ray Afterglow Observed with Chandra
  22. GRB020813, UBVRI field calibration
  23. GRB 020813: addendum to GCN 1498
  24. GRB020813: optical observations at Bisei
  25. GRB020813: V-band decay slope
  26. GRB020812: NIR observations
  27. Polarimetry of GRB020813: evidence for variability
  28. GRB020813 IRAM millimeter observations
  29. GRB020812: optical observations
  30. GRB020813: High-Resolution Optical Observations
  31. GRB020813(=H2262): Revised Localization with HETE SXC
  32. GRB 020812: optical observation at Bisei
  33. GRB020813: Early Time Magnitude
  34. GRB020813: optical observations; possible host galaxy
  35. GRB 020813, radio detection
  36. GRB 020812 : optical afterglow candidate
  37. GRB020813, optical observations
  38. Millimeter observation of GRB 020813
  39. GRB020812: optical observations
  40. GRB 020813 : KISO multiband optical observations
  41. GRB020813, optical observations
  42. IPN error box for GRB020813
  43. IPN triangulation of GRB020813
  44. GRB020812: possible afterglow candidate
  45. Early Time Limits for GRB020813
  46. GRB020812: possible afterglow candidate
  47. GRB020813, astrometric position
  48. Spectropolarimetry of GRB 020813
  49. GRB 020813 Afterglow Observations; Possible break
  50. GRB 020813: Absorption redshift
  51. GRB 020813 multiband optical observations
  52. GRB020813: optical afterglow
  53. GRB020813: Fading of Candidate OT
  54. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  55. GRB020813: Candidate Optical Afterglow
  56. GRB 020812 optical observation
  57. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  58. GRB 020715, optical observations
  59. GRB 020714, optical observations
  60. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  61. GRB020801: Candidate OT present in DSS
  62. HST Imaging of the Host of GRB 011121
  63. GRB020801, optical afterglow candidate
  64. Further refinement to IPN error box for GRB020531
  65. GRB020331: Late-time Optical Light Curve (re-submission)
  66. GRB020331: Late-time Optical Light Curve
  67. GRB 020405: HST observations reveal red bump
  68. IPN triangulation of GRB020714
  69. IPN triangulation of GRB020715 (=GRB150702)
  70. IPN triangulation of GRB020714
  71. IPN triangulation of GRB150702
  72. GRB 020410: Discovery of Probable OT by HST
  73. GRB 020124, HST observations of the fading afterglow
  74. IPN triangulation of GRB020708
  75. IPN triangulation of GRB020708
  76. IPN error box for GRB020706
  77. Correction to IPN error box for GRB020706
  78. IPN triangulation of GRB020706
  79. GRB 020705: Optical observations
  80. GRB 020625, optical observations
  81. GRB 020625: Optical observations
  82. GRB 020531: optical photometry of Chandra sources
  83. GRB020625 (=H2081): A Long Burst Localized by HETE
  84. HETE #2081: Optical observations
  85. The Probable Host Galaxy of GRB/XRF 020427
  86. GRB/XRF 020427, detection of an underlying system with the VLT
  87. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  88. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  89. AXP 1E2259+586: quasi-simultaneous optical observation
  90. AXP 1E2259+586 optical observations
  91. Fading Optical Source in the Field of GRB020531
  92. GRB 020531, INT+WFC deep optical upper limits
  93. SGR-like Bursts from the AXP 1E 2259+586
  94. GRB020405: polarimetric observations
  95. GRB 020531, simultaneous optical observations
  96. GRB 020604, optical observations
  97. GRB 020531/Candidate Redshift
  98. GRB020531: Detection of Candidate Host Galaxy
  99. GRB020531: Second epoch Chandra observations
  100. GRB020604, optical observations

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