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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"

35448 results found.

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

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