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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"

35350 results found.

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

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