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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"

35341 results found.

  1. GRB 011130, Radio/X-ray Comparison
  2. GRB 011212: optical observation at Asiago
  3. GRB 011211: Evidence for an Optical Break
  4. GRB 011211: TNG Spectroscopic Observations
  5. optical follow-up of GRB(XRF) 011211
  6. GRB 011212: optical observation at Oslo (relayed)
  7. GRB 011211: Optical Spectroscopy
  8. GRB 011211, Optical Observations
  9. GRB011212, BVRI field photometry
  10. GRB011211, BVRI field photometry
  11. GRB011212: Optical observations
  12. GRB 011211: BVRi-band photometry
  13. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  14. Fading of the optical source associated of XRF 011211
  15. GRB 011211 Optical Observations: Likely Afterglow
  16. BeppoSAX Alert: GRB011211(=XRF011211)
  17. GRB 011130: Optical Observations of Chandra Sources
  18. GRB 011130: Optical Observations of Chandra sources
  19. GRB 011130: Magellan spectroscopy
  20. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  21. GRB011130, optical observations
  22. GRB 011130, K band observations
  23. GRB011130, optical observations
  24. GRB 011130 I-band Observation
  25. GRB011130 (XRF011130) optical observations
  26. GRB011130 (XRF011130) SDSS PT i-band observations
  27. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  28. XRF011130: NEAT Optical Observations
  29. GRB011130 (=XRF011130): Revised Localization of an X-ray
  30. GRB001109, Radio Monitoring
  31. GRB 011121: Errata URL
  32. GRB 011121
  33. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  34. GRB 011121: J-band observations
  35. GRB 011121: NIR observations, host galaxy?
  36. GRB 011121: HST Scheduled
  37. GRB011121: fainter still
  38. Correction: GCN1157 (GRB 011121)
  39. GRB 011121: Radio Observations
  40. GRB 011121 J-Band Astrometry
  41. GRB011121: continued decay
  42. GRB 011121: Detection of Bright IR Counterpart
  43. GRB011121: possible redshift, continued decay
  44. IPN triangulation of GRB011121
  45. BEPPOSAX GRB011121
  46. GRB 011030: TNG K-band observation
  47. XRF011030: Chandra Observations
  48. GRB 011030: K-band observations
  49. GRB 011030 R band observations
  50. GRB 011030 I-band Observation
  51. The X-ray Flash 011030 ('GRB 011030')
  52. Non-triggered burst 011030 ("GRB 011030")
  53. The Radio Afterglow from the X-ray Rich GRB 011030
  54. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  55. GRB 970828: HST Observations of the Host Galaxy
  56. GRB 000131: HST Detection of the Host Galaxy
  57. GRB 970828: HST Observations of the Host Galaxy
  58. GRB010921, optical observation
  59. GRB 011019 optical observation
  60. GRB011019: Subaru Optical Observations
  61. GRB 011030 I-band Observations
  62. GRB 011030 K-band Observations
  63. GRB010921, optical observations
  64. GRB 011030, WSRT radio observations
  65. GRB011030 - further refinement WFC position
  66. GRB 011030, Radio observations
  67. GRB 011030, R-band observations
  68. BeppoSAX ALERT: Possible X-ray rich GRB011030
  69. GRB 010921: Possible supernova component
  70. GRB011019: NEAT Optical Observations
  71. GRB010921, optical observation at early time
  72. GRB 010921, I-band observations
  73. GRB011019: Optical observations
  74. GRB011019, optical observations
  75. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  76. GRB010921: Spectroscopy of the Host Galaxy
  77. GRB 010921: The afterglow of HETE #1761
  78. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  79. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  80. GRB010923 as seen by BeppoSAX GRBM
  81. GRB010928(=H1770): Localization of a Long GRB by HETE
  82. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  83. GRB010921, negative optical observations
  84. GRB010921 field photometry
  85. GRB010921 Optical Observations
  86. GRB 010921 DPOSS Images Available
  87. IPN triangulation of GRB010921 (=H1761)
  88. H1761: A Bright GRB Detected by HETE
  89. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  90. HETE Trigger #1760 (GRB 010920B?): a new optical source
  91. HETE Trigger #1759 (GRB 010920?) optical observations
  92. GRB001109, Host Galaxy Astrometry
  93. GRB000926, Host Galaxy Observations
  94. GRB001109, Host Galaxy Spectroscopic Observations
  95. Probable SGR or Short Duration GRB Detected by HETE
  96. GRB000926 Host Galaxy Observations
  97. GRB 010222: HST observations -- host galaxy and late-time decay
  98. BeppoSAX/GRBM detection of GRB 010801
  99. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  100. GRB 010222 - WHT BVRI images

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