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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"

37943 results found.

  1. GRB 011211, spectrum and optical photometry
  2. GRB 011130: Optical Observations of X-ray and Radio Sources
  3. GRB 011130, Radio/X-ray Comparison
  4. GRB 011212: optical observation at Asiago
  5. GRB 011211: Evidence for an Optical Break
  6. GRB 011211: TNG Spectroscopic Observations
  7. optical follow-up of GRB(XRF) 011211
  8. GRB 011212: optical observation at Oslo (relayed)
  9. GRB 011211: Optical Spectroscopy
  10. GRB 011211, Optical Observations
  11. GRB011212, BVRI field photometry
  12. GRB011211, BVRI field photometry
  13. GRB011212: Optical observations
  14. GRB 011211: BVRi-band photometry
  15. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  16. Fading of the optical source associated of XRF 011211
  17. GRB 011211 Optical Observations: Likely Afterglow
  18. BeppoSAX Alert: GRB011211(=XRF011211)
  19. GRB 011130: Optical Observations of Chandra Sources
  20. GRB 011130: Optical Observations of Chandra sources
  21. GRB 011130: Magellan spectroscopy
  22. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  23. GRB011130, optical observations
  24. GRB 011130, K band observations
  25. GRB011130, optical observations
  26. GRB 011130 I-band Observation
  27. GRB011130 (XRF011130) optical observations
  28. GRB011130 (XRF011130) SDSS PT i-band observations
  29. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  30. XRF011130: NEAT Optical Observations
  31. GRB011130 (=XRF011130): Revised Localization of an X-ray
  32. GRB001109, Radio Monitoring
  33. GRB 011121: Errata URL
  34. GRB 011121
  35. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  36. GRB 011121: J-band observations
  37. GRB 011121: NIR observations, host galaxy?
  38. GRB 011121: HST Scheduled
  39. GRB011121: fainter still
  40. Correction: GCN1157 (GRB 011121)
  41. GRB 011121: Radio Observations
  42. GRB 011121 J-Band Astrometry
  43. GRB011121: continued decay
  44. GRB 011121: Detection of Bright IR Counterpart
  45. GRB011121: possible redshift, continued decay
  46. IPN triangulation of GRB011121
  47. BEPPOSAX GRB011121
  48. GRB 011030: TNG K-band observation
  49. XRF011030: Chandra Observations
  50. GRB 011030: K-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. GRB011019: Subaru Optical Observations
  63. GRB 011030 I-band Observations
  64. GRB 011030 K-band Observations
  65. GRB010921, optical observations
  66. GRB 011030, WSRT radio observations
  67. GRB011030 - further refinement WFC position
  68. GRB 011030, Radio observations
  69. GRB 011030, R-band observations
  70. BeppoSAX ALERT: Possible X-ray rich GRB011030
  71. GRB 010921: Possible supernova component
  72. GRB011019: NEAT Optical Observations
  73. GRB010921, optical observation at early time
  74. GRB 010921, I-band observations
  75. GRB011019: Optical observations
  76. GRB011019, optical observations
  77. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  78. GRB010921: Spectroscopy of the Host Galaxy
  79. GRB 010921: The afterglow of HETE #1761
  80. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  81. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  82. GRB010923 as seen by BeppoSAX GRBM
  83. GRB010928(=H1770): Localization of a Long GRB by HETE
  84. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  85. GRB010921, negative optical observations
  86. GRB010921 field photometry
  87. GRB010921 Optical Observations
  88. GRB 010921 DPOSS Images Available
  89. IPN triangulation of GRB010921 (=H1761)
  90. H1761: A Bright GRB Detected by HETE
  91. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  92. HETE Trigger #1760 (GRB 010920B?): a new optical source
  93. HETE Trigger #1759 (GRB 010920?) optical observations
  94. GRB001109, Host Galaxy Astrometry
  95. GRB000926, Host Galaxy Observations
  96. GRB001109, Host Galaxy Spectroscopic Observations
  97. Probable SGR or Short Duration GRB Detected by HETE
  98. GRB000926 Host Galaxy Observations
  99. GRB 010222: HST observations -- host galaxy and late-time decay
  100. BeppoSAX/GRBM detection of GRB 010801

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