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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"

17041 results found.

  1. GRB 011130, K band observations
  2. GRB011130 (XRF011130) SDSS PT i-band observations
  3. XRF011130: Infrared Observations
  4. GRB 011121: J-band observations
  5. GRB 011121: NIR observations, host galaxy?
  6. GRB011121: UBRI Observations
  7. GRB 011121 J-Band Astrometry
  8. GRB 011121: Detection of Bright IR Counterpart
  9. GRB011121: possible redshift, continued decay
  10. GRB 011030: TNG K-band observation
  11. XRF011030: J and K band observations
  12. XRF011030: Chandra Observations
  13. GRB011030: Z-band observations
  14. Non-triggered burst 011030 ("GRB 011030")
  15. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  16. GRB 970828: HST Observations of the Host Galaxy
  17. GRB 000131: HST Detection of the Host Galaxy
  18. GRB 970828: HST Observations of the Host Galaxy
  19. GRB010921, optical observation
  20. GRB011019: Subaru Optical Observations
  21. GRB011030 - further refinement WFC position
  22. GRB011030: radio search
  23. GRB 010921: Possible supernova component
  24. GRB010921, optical observation at early time
  25. GRB 010921, I-band observations
  26. GRB011019, optical observations
  27. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  28. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  29. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  30. GRB010928(=H1770): Localization of a Long GRB by HETE
  31. GRB010921, negative optical observations
  32. GRB010921 field photometry
  33. GRB000926, Host Galaxy Observations
  34. GRB001109, Host Galaxy Spectroscopic Observations
  35. Probable SGR or Short Duration GRB Detected by HETE
  36. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  37. GRB 010222 - WHT BVRI images
  38. GRB 010629 Optical Observations
  39. SGR1900+14: High Fluence Burst Localized by HETE
  40. GRB010629, optical observations
  41. IPN triangulation of GRB010629
  42. GRB010629: A Burst Localized by HETE
  43. SGR1900+14: Second Burst Localized by HETE
  44. SGR1900+14: A Burst Localized by HETE
  45. SGR1806-20: A Second, Intense Burst Localized by HETE
  46. SGR1806-20: Localization by HETE
  47. HETE Fully-Automated GCN Notices
  48. GRB000301C: Late-time HST/STIS observation
  49. GRB010518: a faint BeppoSAX detection
  50. GRB000418: HST/STIS Second-epoch Observations
  51. X-ray precursors to the large flare from SGR 1900+14
  52. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  53. Millimeter observation of SGR 1900+14
  54. Chandra Observations of SGR 1900+14
  55. SGR1900+14, I-band observations
  56. GRB010412, field photometry
  57. Giant flare from SGR1900+14
  58. GRB 010326b Optical Observations
  59. GRB010412: BeppoSAX GRBM and WFC observations
  60. IPN Triangulation of GRB010412
  61. GRB010324, revised field photometry
  62. GRB 980326: Late-time HST/STIS observations
  63. GRB010324, field photometry
  64. GRB010326B, field photometry
  65. GRB010326, field photometry
  66. GRB010220, field photometry
  67. Further Optical Observations of GRB 010324
  68. GRB010222, CXO X-ray observations
  69. GRB010324, optical observations
  70. GRB010326B: Localization by HETE (2nd GRB for this date)
  71. GRB 010326 optical observations
  72. GRB010326: Refined Localization by HETE
  73. GRB010326: Localization by HETE
  74. Optical Observations of GRB 010324
  75. GRB010222, late-time optical observation
  76. Support extension to the BeppoSAX mission
  77. GRB 010222, Optical Observations
  78. GRB 010222: High-Resolution Keck Spectroscopy
  79. GRB 010222 HST/Chandra TOO
  80. GRB010222 further R-band photometry
  81. GRB 010222: Keck Spectroscopy
  82. GRB010214, field photometry
  83. GRB010222, field photometry
  84. GRB010222 further R-band photometry
  85. GRB 010222 Kyoto optical observation
  86. GRB010222 R-BAND OBSERVATION
  87. GRB010214 follow-up from Hanle
  88. GRB 010222: Near-IR Observations
  89. GRB 010222: Optical Observations
  90. GRB010222, radio observations
  91. GRB010222, optical observations
  92. GRB010222: BeppoSAX/NFI Observations
  93. GRB 010220, simultaneous optical observations
  94. GRB010220: BeppoSAX WFC and GRBM preliminary data
  95. GRB010214, optical observations
  96. GRB010214: BeppoSAX WFC and GRBM preliminary data
  97. GRB 010214: X-Ray afterglow
  98. GRB 010214 optical observation
  99. J-Band Observation of GRB 010214.
  100. GRB010213, Near-IR observations

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