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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"

35254 results found.

  1. GRB 020124: Optical observations
  2. GRB 020124 Optical Observations
  3. IPN triangulation of GRB020124 (HETE 1896)
  4. IPN observations of SGR1806-20
  5. GRB 020124: Optical afterglow
  6. GRB020124(=H1896): Localization of a Long GRB by HETE
  7. GRB optical counterpart candidate in GCN 1217 is M dwarf
  8. Possible optical counterpart to a GRB
  9. GRB011212, Optical Observations
  10. GRB 011211: Detection of the Probable Host Galaxy
  11. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  12. GRB 011211, spectrum and optical photometry
  13. GRB 011130: Optical Observations of X-ray and Radio Sources
  14. GRB 011130, Radio/X-ray Comparison
  15. GRB 011212: optical observation at Asiago
  16. GRB 011211: Evidence for an Optical Break
  17. GRB 011211: TNG Spectroscopic Observations
  18. optical follow-up of GRB(XRF) 011211
  19. GRB 011212: optical observation at Oslo (relayed)
  20. GRB 011211: Optical Spectroscopy
  21. GRB 011211, Optical Observations
  22. GRB011212, BVRI field photometry
  23. GRB011211, BVRI field photometry
  24. GRB011212: Optical observations
  25. GRB 011211: BVRi-band photometry
  26. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  27. Fading of the optical source associated of XRF 011211
  28. GRB 011211 Optical Observations: Likely Afterglow
  29. BeppoSAX Alert: GRB011211(=XRF011211)
  30. GRB 011130: Optical Observations of Chandra Sources
  31. GRB 011130: Optical Observations of Chandra sources
  32. GRB 011130: Magellan spectroscopy
  33. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  34. GRB011130, optical observations
  35. GRB 011130, K band observations
  36. GRB011130, optical observations
  37. GRB 011130 I-band Observation
  38. GRB011130 (XRF011130) optical observations
  39. GRB011130 (XRF011130) SDSS PT i-band observations
  40. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  41. XRF011130: NEAT Optical Observations
  42. GRB011130 (=XRF011130): Revised Localization of an X-ray
  43. GRB001109, Radio Monitoring
  44. GRB 011121: Errata URL
  45. GRB 011121
  46. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  47. GRB 011121: J-band observations
  48. GRB 011121: NIR observations, host galaxy?
  49. GRB 011121: HST Scheduled
  50. GRB011121: fainter still
  51. Correction: GCN1157 (GRB 011121)
  52. GRB 011121: Radio Observations
  53. GRB 011121 J-Band Astrometry
  54. GRB011121: continued decay
  55. GRB 011121: Detection of Bright IR Counterpart
  56. GRB011121: possible redshift, continued decay
  57. IPN triangulation of GRB011121
  58. BEPPOSAX GRB011121
  59. GRB 011030: TNG K-band observation
  60. XRF011030: Chandra Observations
  61. GRB 011030: K-band observations
  62. GRB 011030 R band observations
  63. GRB 011030 I-band Observation
  64. The X-ray Flash 011030 ('GRB 011030')
  65. Non-triggered burst 011030 ("GRB 011030")
  66. The Radio Afterglow from the X-ray Rich GRB 011030
  67. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  68. GRB 970828: HST Observations of the Host Galaxy
  69. GRB 000131: HST Detection of the Host Galaxy
  70. GRB 970828: HST Observations of the Host Galaxy
  71. GRB010921, optical observation
  72. GRB 011019 optical observation
  73. GRB011019: Subaru Optical Observations
  74. GRB 011030 I-band Observations
  75. GRB 011030 K-band Observations
  76. GRB010921, optical observations
  77. GRB 011030, WSRT radio observations
  78. GRB011030 - further refinement WFC position
  79. GRB 011030, Radio observations
  80. GRB 011030, R-band observations
  81. BeppoSAX ALERT: Possible X-ray rich GRB011030
  82. GRB 010921: Possible supernova component
  83. GRB011019: NEAT Optical Observations
  84. GRB010921, optical observation at early time
  85. GRB 010921, I-band observations
  86. GRB011019: Optical observations
  87. GRB011019, optical observations
  88. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  89. GRB010921: Spectroscopy of the Host Galaxy
  90. GRB 010921: The afterglow of HETE #1761
  91. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  92. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  93. GRB010923 as seen by BeppoSAX GRBM
  94. GRB010928(=H1770): Localization of a Long GRB by HETE
  95. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  96. GRB010921, negative optical observations
  97. GRB010921 field photometry
  98. GRB010921 Optical Observations
  99. GRB 010921 DPOSS Images Available
  100. IPN triangulation of GRB010921 (=H1761)

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