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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"

20380 results found.

  1. GRB020124: Optical observations
  2. GRB 020124: Optical observations
  3. Possible optical counterpart to a GRB
  4. GRB011212, Optical Observations
  5. Optical polarization observations for GRB011211
  6. GRB 011211: Detection of the Probable Host Galaxy
  7. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  8. GRB 011130: Optical Observations of X-ray and Radio Sources
  9. GRB 011130, Radio/X-ray Comparison
  10. GRB 011212: optical observation at Asiago
  11. GRB 011211: Evidence for an Optical Break
  12. GRB 011212: optical observation at Oslo (relayed)
  13. GRB 011211, Optical Observations
  14. GRB011212, BVRI field photometry
  15. GRB011211, BVRI field photometry
  16. Fading of the optical source associated of XRF 011211
  17. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  18. BeppoSAX Alert: GRB011211(=XRF011211)
  19. GRB011130 (XRF011130) Chandra Observations
  20. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  21. GRB 011130, K band observations
  22. GRB011130 (XRF011130) SDSS PT i-band observations
  23. XRF011130: Infrared Observations
  24. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  25. GRB 011121: J-band observations
  26. GRB 011121: NIR observations, host galaxy?
  27. GRB010921 - Milagro GeV/TeV Observations
  28. GRB011121: UBRI Observations
  29. GRB 011121: Radio Observations
  30. GRB 011121 J-Band Astrometry
  31. GRB 011121: Detection of Bright IR Counterpart
  32. GRB011121: possible redshift, continued decay
  33. IPN triangulation of GRB011121
  34. BEPPOSAX GRB011121
  35. GRB 011030: TNG K-band observation
  36. XRF011030: J and K band observations
  37. XRF011030: Chandra Observations
  38. GRB011030: Z-band observations
  39. GRB 011030 R band observations
  40. Non-triggered burst 011030 ("GRB 011030")
  41. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  42. GRB 970828: HST Observations of the Host Galaxy
  43. GRB 000131: HST Detection of the Host Galaxy
  44. GRB 970828: HST Observations of the Host Galaxy
  45. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  46. GRB011019: Subaru Optical Observations
  47. GRB011030 - further refinement WFC position
  48. GRB011030: radio search
  49. GRB 011030, R-band observations
  50. BeppoSAX ALERT: Possible X-ray rich GRB011030
  51. GRB 010921: Possible supernova component
  52. GRB010921, optical observation at early time
  53. GRB 010921, I-band observations
  54. GRB011019, optical observations
  55. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  56. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  57. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  58. GRB010928(=H1770): Localization of a Long GRB by HETE
  59. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  60. GRB010921, negative optical observations
  61. GRB010921 field photometry
  62. H1761: A Bright GRB Detected by HETE
  63. GRB000926, Host Galaxy Observations
  64. GRB001109, Host Galaxy Spectroscopic Observations
  65. GRB 010222: HST observations -- host galaxy and late-time decay
  66. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  67. GRB 010222 - WHT BVRI images
  68. GRB 010629 Optical Observations
  69. SGR1900+14: High Fluence Burst Localized by HETE
  70. GRB010629, optical observations
  71. IPN triangulation of GRB010629
  72. GRB010629: A Burst Localized by HETE
  73. SGR1900+14: Second Burst Localized by HETE
  74. SGR1900+14: A Burst Localized by HETE
  75. SGR1806-20: A Second, Intense Burst Localized by HETE
  76. SGR1806-20: Localization by HETE
  77. HETE Fully-Automated GCN Notices
  78. GRB000301C: Late-time HST/STIS observation
  79. GRB010518: a faint BeppoSAX detection
  80. GRB000418: HST/STIS Second-epoch Observations
  81. X-ray precursors to the large flare from SGR 1900+14
  82. GRB010427, Gamma Ray Observations
  83. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  84. SGR 1900+14: Correction to GCN 1049
  85. Millimeter observation of SGR 1900+14
  86. SGR 1900+14: Detection of extended X-ray emission
  87. SGR 1900+14, Chandra observations
  88. Possible precursor to the SGR1900+14 giant burst
  89. SGR1900+14, I-band observations
  90. IPN Triangulation of the Giant Flare from SGR1900+14
  91. GRB010412, field photometry
  92. Giant flare from SGR1900+14
  93. GRB 010326b Optical Observations
  94. GRB010412: BeppoSAX GRBM and WFC observations
  95. GRB010324, revised field photometry
  96. REVISED LOCATION OF GRB010326A
  97. GRB 980326: Late-time HST/STIS observations
  98. GRB010324, field photometry
  99. GRB010326B, field photometry
  100. GRB010326, field photometry

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