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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"

16000 results found.

  1. GRB010629: A Burst Localized by HETE
  2. SGR1900+14: Second Burst Localized by HETE
  3. SGR1900+14: A Burst Localized by HETE
  4. SGR1806-20: A Second, Intense Burst Localized by HETE
  5. GRB 00630: Host Galaxy
  6. SGR1806-20: Localization by HETE
  7. GRB000418: HST/STIS Second-epoch Observations
  8. GRB010214, optical observations
  9. GRB010412, field photometry
  10. GRB 010326b Optical Observations
  11. GRB010412: Optical observations
  12. GRB010412: Optical observations
  13. GRB010324, revised field photometry
  14. GRB010326B, field photometry
  15. GRB010326, field photometry
  16. Further Optical Observations of GRB 010324
  17. GRB010222, CXO X-ray observations
  18. GRB 010326A: Further optical observations
  19. GRB 010326B: Optical observations
  20. GRB010324, optical observations
  21. GRB010326B: Localization by HETE (2nd GRB for this date)
  22. GRB 010326: Optical observations
  23. GRB 010326 optical observations
  24. GRB010326: Refined Localization by HETE
  25. GRB010326: Localization by HETE
  26. Optical Observations of GRB 010324
  27. GRB010222, late-time optical observation
  28. GRB010222 - Optical observation
  29. GRB 010222, Optical Observations
  30. GRB010220 optical obsercations
  31. GRB010222 - Optical observation
  32. GRB 010222: High-Resolution Keck Spectroscopy
  33. GRB010222: Optical observation and decay
  34. GRB 010214, I-band data
  35. GRB 010222 HST/Chandra TOO
  36. GRB 010222
  37. GRB010222: R-band data
  38. GRB010222 Optical observations
  39. GRB 010222: Keck Spectroscopy
  40. GRB010222, possible increase of optical decay slope
  41. GRB 010222 Kyoto optical observation
  42. GRB010222: fading behavior
  43. GRB 010222 BV optical observations
  44. GRB010220, Optical Observations
  45. GRB010214 follow-up from Hanle
  46. GRB 010222: Near-IR Observations
  47. GRB 010222: Optical Observations
  48. GRB 010222, Decay Slope Confirmed
  49. GRB010222: Another absorption line system
  50. GRB010222: Optical decay slope
  51. GRB 010214, Optical Observations
  52. GRB010222: Sub-millimeter detection
  53. GRB010222: R-band fading behavior
  54. GRB010222: Optical Observations
  55. GRB010222, radio observations
  56. GRB010222, optical observations
  57. GRB010222: BeppoSAX/NFI Observations
  58. Redshift of the Optical Transient of GRB010222
  59. GRB010222: possible optical counterpart
  60. GRB010222
  61. GRB010220, Radio and Optical Observations
  62. GRB 010220, simultaneous optical observations
  63. GRB010214, candidate optical afterglow
  64. GRB010214, optical observations
  65. GRB 010214, Optical Observations
  66. GRB 010214 optical observation
  67. GRB010213 Optical Observation
  68. GRB010213, Radio Observations
  69. GRB010214, optical observations
  70. GRB010213, optical observations
  71. GRB010214 Optical Observation
  72. GRB 010214, optical observations
  73. GRB010213 detected by HETE
  74. HETE Status
  75. GRB010126: CONCAM crude optical limits during GRB
  76. GRB010126, TNG R-band observations
  77. GRB010126 Optical Observations
  78. GRB010126 optical observations
  79. GRB010126: Optical observations
  80. GRB 010119, optical observations
  81. GRB010119: Optical observations
  82. Optical Observations of GRB 001018 at Keck
  83. Optical observations of GRB 001018 with JCAM
  84. GRB010103, optical observations
  85. GRB 001212 Optical Observation
  86. GRB 001212 Optical Observation
  87. GRB 001212 optical observation
  88. GRB 001212 possible OA in 2MASS
  89. GRB 001212 possible OA
  90. GRB001204: Optical observations
  91. GRB 001105, further optical observations
  92. GRB001120: Gunn-i observations
  93. GRB001120: Optical observations
  94. GRB001109, optical observations
  95. GRB001120, optical observations
  96. Optical/NIR observations of GRB001109
  97. GRB 001109: deep JHK upper limits
  98. GRB001109: Optical observations
  99. GRB001109, R-band optical observations
  100. GRB001109, Radio observations

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