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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"

26500 results found.

  1. GRB 011121: NIR observations, host galaxy?
  2. GRB010921 - Milagro GeV/TeV Observations
  3. GRB011121: UBRI Observations
  4. GRB011121
  5. GRB 011121: Radio Observations
  6. GRB 011121 J-Band Astrometry
  7. GRB 011121: Detection of Bright IR Counterpart
  8. GRB011121: possible redshift, continued decay
  9. GRB011121: BeppoSAX-WFC refined positions
  10. IPN triangulation of GRB011121
  11. GRB 011030: TNG K-band observation
  12. XRF011030: J and K band observations
  13. XRF011030: Chandra Observations
  14. GRB011030: Z-band observations
  15. GRB 011030 I-band Observation
  16. The X-ray Flash 011030 ('GRB 011030')
  17. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  18. GRB 970828: HST Observations of the Host Galaxy
  19. GRB 000131: HST Detection of the Host Galaxy
  20. GRB 970828: HST Observations of the Host Galaxy
  21. GRB010921, optical observation
  22. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  23. GRB011019: Subaru Optical Observations
  24. GRB010921, optical observations
  25. GRB011030 - further refinement WFC position
  26. GRB011030: radio search
  27. GRB 011030, R-band observations
  28. GRB 010921: Possible supernova component
  29. GRB011019: ROTSE-III optical observations
  30. GRB010921, optical observation at early time
  31. GRB 010921, I-band observations
  32. GRB011019, optical observations
  33. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  34. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  35. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  36. GRB010923 as seen by BeppoSAX GRBM
  37. GRB010928(=H1770): Localization of a Long GRB by HETE
  38. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  39. GRB010921, negative optical observations
  40. GRB010921 field photometry
  41. H1761: A Bright GRB Detected by HETE
  42. HETE Trigger #1760 (GRB 010920B?): a new optical source
  43. GRB000926, Host Galaxy Observations
  44. GRB001109, Host Galaxy Spectroscopic Observations
  45. Probable SGR or Short Duration GRB Detected by HETE
  46. GRB 010222: HST observations -- host galaxy and late-time decay
  47. BeppoSAX/GRBM detection of GRB 010801
  48. GCN and HETE status
  49. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  50. GRB 010222 - WHT BVRI images
  51. SGR1900+14 burst seen by HETE: BeppoSAX data
  52. GRB 010629 Optical Observations
  53. SGR1900+14: High Fluence Burst Localized by HETE
  54. GRB010629, optical observations
  55. IPN triangulation of GRB010629
  56. GRB010629: A Burst Localized by HETE
  57. SGR1900+14: Second Burst Localized by HETE
  58. SGR1900+14: A Burst Localized by HETE
  59. Possible burst from SGR1806-20
  60. IPN detection of SGR1900+14
  61. SGR1806-20: A Second, Intense Burst Localized by HETE
  62. GRB 00630: Host Galaxy
  63. SGR1806-20: Localization by HETE
  64. IPN triangulation of GRB010613
  65. IPN triangulation of GRB010612
  66. HETE Fully-Automated GCN Notices
  67. GRB000301C: Late-time HST/STIS observation
  68. GRB010518: a faint BeppoSAX detection
  69. GRB000418: HST/STIS Second-epoch Observations
  70. X-ray precursors to the large flare from SGR 1900+14
  71. GRB010427, Gamma Ray Observations
  72. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  73. SGR 1900+14: Correction to GCN 1049
  74. Millimeter observation of SGR 1900+14
  75. SGR 1900+14: Detection of extended X-ray emission
  76. Chandra Observations of SGR 1900+14
  77. SGR 1900+14, Chandra observations
  78. Chandra Observations of SGR 1900+14
  79. Possible precursor to the SGR1900+14 giant burst
  80. SGR1900+14, I-band observations
  81. IPN Triangulation of the Giant Flare from SGR1900+14
  82. GRB010412, field photometry
  83. Giant flare from SGR1900+14
  84. GRB 010326b Optical Observations
  85. GRB010412: BeppoSAX GRBM and WFC observations
  86. IPN Triangulation of GRB010412
  87. GRB Observation Report
  88. GRB010324, revised field photometry
  89. GRB 980326: Late-time HST/STIS observations
  90. GRB010324, field photometry
  91. GRB010326B, field photometry
  92. GRB010326, field photometry
  93. GRB010220, field photometry
  94. Further Optical Observations of GRB 010324
  95. GRB010222, CXO X-ray observations
  96. GRB 010326A: Further optical observations
  97. GRB010324: BeppoSAX/GRBM data
  98. GRB 010326B: Optical observations
  99. GRB010324, optical observations
  100. GRB010326B: Localization by HETE (2nd GRB for this date)

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