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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. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  2. GRB011211(=XRF011211): BeppoSAX refined positions
  3. BeppoSAX Alert: GRB011211(=XRF011211)
  4. GRB 011130: Optical Observations of Chandra Sources
  5. GRB 011130: Optical Observations of Chandra sources
  6. GRB011130 (XRF011130) Chandra Observations
  7. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  8. GRB 011130: Magellan spectroscopy
  9. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  10. GRB011130, optical observations
  11. GRB 011130, K band observations
  12. GRB011130, optical observations
  13. GRB011130 (=XRF011130): Second Revised Localization by HETE
  14. GRB 011130 I-band Observation
  15. GRB011130 (XRF011130) optical observations
  16. GRB011130 (XRF011130) SDSS PT i-band observations
  17. XRF011130: Infrared Observations
  18. GRB011130, Radio Observations
  19. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  20. GRB011130 (=XRF011130), Optical Observations
  21. XRF011130: NEAT Optical Observations
  22. GRB011130 (=XRF011130): Revised Localization of an X-ray
  23. GRB001109, Radio Monitoring
  24. GRB 011121: Errata URL
  25. GRB 011121
  26. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  27. GRB 011121: J-band observations
  28. GRB 011121: NIR observations, host galaxy?
  29. GRB010921 - Milagro GeV/TeV Observations
  30. GRB 011121: HST Scheduled
  31. GRB011121: fainter still
  32. Correction: GCN1157 (GRB 011121)
  33. GRB011121: UBRI Observations
  34. GRB011121
  35. GRB 011121: Radio Observations
  36. GRB 011121 J-Band Astrometry
  37. GRB011121: continued decay
  38. GRB 011121: Detection of Bright IR Counterpart
  39. GRB011121: possible redshift, continued decay
  40. GRB011121: fading behavior
  41. GRB011121: possible optical counterpart
  42. GRB011121: BeppoSAX-WFC refined positions
  43. IPN triangulation of GRB011121
  44. BEPPOSAX GRB011121
  45. GRB 011030: TNG K-band observation
  46. XRF011030: J and K band observations
  47. GRB011030, optical observation
  48. XRF011030: Chandra Observations
  49. GRB 011030: K-band observations
  50. GRB011030: Z-band observations
  51. GRB 011030 R band observations
  52. GRB 011030 I-band Observation
  53. The X-ray Flash 011030 ('GRB 011030')
  54. Non-triggered burst 011030 ("GRB 011030")
  55. The Radio Afterglow from the X-ray Rich GRB 011030
  56. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  57. GRB 970828: HST Observations of the Host Galaxy
  58. GRB 000131: HST Detection of the Host Galaxy
  59. GRB 970828: HST Observations of the Host Galaxy
  60. GRB010921, optical observation
  61. GRB 011019 optical observation
  62. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  63. GRB011019: Subaru Optical Observations
  64. GRB 011030 I-band Observations
  65. GRB 011030 K-band Observations
  66. GRB010921, optical observations
  67. GRB 011030, WSRT radio observations
  68. GRB011030 - further refinement WFC position
  69. GRB 011030, Radio observations
  70. GRB011030: radio search
  71. GRB 011030, R-band observations
  72. X-ray rich GRB011030: BeppoSAX refined positions
  73. BeppoSAX ALERT: Possible X-ray rich GRB011030
  74. GRB 010921: Possible supernova component
  75. GRB011019: NEAT Optical Observations
  76. GRB011019: ROTSE-III optical observations
  77. GRB010921, optical observation at early time
  78. GRB 010921, I-band observations
  79. GRB011019: Optical observations
  80. GRB011019, optical observations -- correction
  81. GRB011019, optical observations
  82. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  83. GRB010921: Spectroscopy of the Host Galaxy
  84. GRB 010921: The afterglow of HETE #1761
  85. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  86. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  87. GRB010923 as seen by BeppoSAX GRBM
  88. GRB010928(=H1770): Localization of a Long GRB by HETE
  89. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  90. GRB010921, negative optical observations
  91. GRB010921 field photometry
  92. GRB010921 Optical Observations
  93. GRB 010921 DPOSS Images Available
  94. IPN triangulation of GRB010921 (=H1761)
  95. H1761: A Bright GRB Detected by HETE
  96. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  97. HETE Trigger #1760 (GRB 010920B?): a new optical source
  98. HETE Trigger #1759 (GRB 010920?) optical observations
  99. GRB001109, Host Galaxy Astrometry
  100. GRB000926, Host Galaxy Observations

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