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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"

37549 results found.

  1. GRB020124(=H1896): Localization of a Long GRB by HETE
  2. GRB optical counterpart candidate in GCN 1217 is M dwarf
  3. Possible optical counterpart to a GRB
  4. GRB011212, Optical Observations
  5. GRB 011211: Detection of the Probable Host Galaxy
  6. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  7. GRB 011211, spectrum and optical photometry
  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 011211: TNG Spectroscopic Observations
  13. optical follow-up of GRB(XRF) 011211
  14. GRB 011212: optical observation at Oslo (relayed)
  15. GRB 011211: Optical Spectroscopy
  16. GRB 011211, Optical Observations
  17. GRB011212, BVRI field photometry
  18. GRB011211, BVRI field photometry
  19. GRB011212: Optical observations
  20. GRB 011211: BVRi-band photometry
  21. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  22. Fading of the optical source associated of XRF 011211
  23. GRB 011211 Optical Observations: Likely Afterglow
  24. BeppoSAX Alert: GRB011211(=XRF011211)
  25. GRB 011130: Optical Observations of Chandra Sources
  26. GRB 011130: Optical Observations of Chandra sources
  27. GRB 011130: Magellan spectroscopy
  28. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  29. GRB011130, optical observations
  30. GRB 011130, K band observations
  31. GRB011130, optical observations
  32. GRB 011130 I-band Observation
  33. GRB011130 (XRF011130) optical observations
  34. GRB011130 (XRF011130) SDSS PT i-band observations
  35. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  36. XRF011130: NEAT Optical Observations
  37. GRB011130 (=XRF011130): Revised Localization of an X-ray
  38. GRB001109, Radio Monitoring
  39. GRB 011121: Errata URL
  40. GRB 011121
  41. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  42. GRB 011121: J-band observations
  43. GRB 011121: NIR observations, host galaxy?
  44. GRB 011121: HST Scheduled
  45. GRB011121: fainter still
  46. Correction: GCN1157 (GRB 011121)
  47. GRB 011121: Radio Observations
  48. GRB 011121 J-Band Astrometry
  49. GRB011121: continued decay
  50. GRB 011121: Detection of Bright IR Counterpart
  51. GRB011121: possible redshift, continued decay
  52. IPN triangulation of GRB011121
  53. BEPPOSAX GRB011121
  54. GRB 011030: TNG K-band observation
  55. XRF011030: Chandra Observations
  56. GRB 011030: K-band observations
  57. GRB 011030 R band observations
  58. GRB 011030 I-band Observation
  59. The X-ray Flash 011030 ('GRB 011030')
  60. Non-triggered burst 011030 ("GRB 011030")
  61. The Radio Afterglow from the X-ray Rich GRB 011030
  62. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  63. GRB 970828: HST Observations of the Host Galaxy
  64. GRB 000131: HST Detection of the Host Galaxy
  65. GRB 970828: HST Observations of the Host Galaxy
  66. GRB010921, optical observation
  67. GRB 011019 optical observation
  68. GRB011019: Subaru Optical Observations
  69. GRB 011030 I-band Observations
  70. GRB 011030 K-band Observations
  71. GRB010921, optical observations
  72. GRB 011030, WSRT radio observations
  73. GRB011030 - further refinement WFC position
  74. GRB 011030, Radio observations
  75. GRB 011030, R-band observations
  76. BeppoSAX ALERT: Possible X-ray rich GRB011030
  77. GRB 010921: Possible supernova component
  78. GRB011019: NEAT Optical Observations
  79. GRB010921, optical observation at early time
  80. GRB 010921, I-band observations
  81. GRB011019: Optical observations
  82. GRB011019, optical observations
  83. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  84. GRB010921: Spectroscopy of the Host Galaxy
  85. GRB 010921: The afterglow of HETE #1761
  86. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  87. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  88. GRB010923 as seen by BeppoSAX GRBM
  89. GRB010928(=H1770): Localization of a Long GRB by HETE
  90. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  91. GRB010921, negative optical observations
  92. GRB010921 field photometry
  93. GRB010921 Optical Observations
  94. GRB 010921 DPOSS Images Available
  95. IPN triangulation of GRB010921 (=H1761)
  96. H1761: A Bright GRB Detected by HETE
  97. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  98. HETE Trigger #1760 (GRB 010920B?): a new optical source
  99. HETE Trigger #1759 (GRB 010920?) optical observations
  100. GRB001109, Host Galaxy Astrometry

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