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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"

37950 results found.

  1. GRB 020124: Optical afterglow
  2. GRB020124(=H1896): Localization of a Long GRB by HETE
  3. GRB optical counterpart candidate in GCN 1217 is M dwarf
  4. Possible optical counterpart to a GRB
  5. GRB011212, Optical Observations
  6. GRB 011211: Detection of the Probable Host Galaxy
  7. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  8. GRB 011211, spectrum and optical photometry
  9. GRB 011130: Optical Observations of X-ray and Radio Sources
  10. GRB 011130, Radio/X-ray Comparison
  11. GRB 011212: optical observation at Asiago
  12. GRB 011211: Evidence for an Optical Break
  13. GRB 011211: TNG Spectroscopic Observations
  14. optical follow-up of GRB(XRF) 011211
  15. GRB 011212: optical observation at Oslo (relayed)
  16. GRB 011211: Optical Spectroscopy
  17. GRB 011211, Optical Observations
  18. GRB011212, BVRI field photometry
  19. GRB011211, BVRI field photometry
  20. GRB011212: Optical observations
  21. GRB 011211: BVRi-band photometry
  22. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  23. Fading of the optical source associated of XRF 011211
  24. GRB 011211 Optical Observations: Likely Afterglow
  25. BeppoSAX Alert: GRB011211(=XRF011211)
  26. GRB 011130: Optical Observations of Chandra Sources
  27. GRB 011130: Optical Observations of Chandra sources
  28. GRB 011130: Magellan spectroscopy
  29. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  30. GRB011130, optical observations
  31. GRB 011130, K band observations
  32. GRB011130, optical observations
  33. GRB 011130 I-band Observation
  34. GRB011130 (XRF011130) optical observations
  35. GRB011130 (XRF011130) SDSS PT i-band observations
  36. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  37. XRF011130: NEAT Optical Observations
  38. GRB011130 (=XRF011130): Revised Localization of an X-ray
  39. GRB001109, Radio Monitoring
  40. GRB 011121: Errata URL
  41. GRB 011121
  42. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  43. GRB 011121: J-band observations
  44. GRB 011121: NIR observations, host galaxy?
  45. GRB 011121: HST Scheduled
  46. GRB011121: fainter still
  47. Correction: GCN1157 (GRB 011121)
  48. GRB 011121: Radio Observations
  49. GRB 011121 J-Band Astrometry
  50. GRB011121: continued decay
  51. GRB 011121: Detection of Bright IR Counterpart
  52. GRB011121: possible redshift, continued decay
  53. IPN triangulation of GRB011121
  54. BEPPOSAX GRB011121
  55. GRB 011030: TNG K-band observation
  56. XRF011030: Chandra Observations
  57. GRB 011030: K-band observations
  58. GRB 011030 R band observations
  59. GRB 011030 I-band Observation
  60. The X-ray Flash 011030 ('GRB 011030')
  61. Non-triggered burst 011030 ("GRB 011030")
  62. The Radio Afterglow from the X-ray Rich GRB 011030
  63. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  64. GRB 970828: HST Observations of the Host Galaxy
  65. GRB 000131: HST Detection of the Host Galaxy
  66. GRB 970828: HST Observations of the Host Galaxy
  67. GRB010921, optical observation
  68. GRB 011019 optical observation
  69. GRB011019: Subaru Optical Observations
  70. GRB 011030 I-band Observations
  71. GRB 011030 K-band Observations
  72. GRB010921, optical observations
  73. GRB 011030, WSRT radio observations
  74. GRB011030 - further refinement WFC position
  75. GRB 011030, Radio observations
  76. GRB 011030, R-band observations
  77. BeppoSAX ALERT: Possible X-ray rich GRB011030
  78. GRB 010921: Possible supernova component
  79. GRB011019: NEAT Optical Observations
  80. GRB010921, optical observation at early time
  81. GRB 010921, I-band observations
  82. GRB011019: Optical observations
  83. GRB011019, optical observations
  84. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  85. GRB010921: Spectroscopy of the Host Galaxy
  86. GRB 010921: The afterglow of HETE #1761
  87. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  88. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  89. GRB010923 as seen by BeppoSAX GRBM
  90. GRB010928(=H1770): Localization of a Long GRB by HETE
  91. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  92. GRB010921, negative optical observations
  93. GRB010921 field photometry
  94. GRB010921 Optical Observations
  95. GRB 010921 DPOSS Images Available
  96. IPN triangulation of GRB010921 (=H1761)
  97. H1761: A Bright GRB Detected by HETE
  98. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  99. HETE Trigger #1760 (GRB 010920B?): a new optical source
  100. HETE Trigger #1759 (GRB 010920?) optical observations

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