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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"

32484 results found.

  1. GRB011212, Optical Observations
  2. GRB011211: BeppoSAX/GRBM data
  3. Optical polarization observations for GRB011211
  4. Color indices of the afterglow of GRB011211
  5. GRB011212: Optical observations at Gunma
  6. GRB 011211, spectrum and optical photometry
  7. GRB 011130: Optical Observations of X-ray and Radio Sources
  8. GRB 011130, Radio/X-ray Comparison
  9. GRB011212: Optical observations
  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. Fading of the optical source associated of XRF 011211
  22. XMM-Newton observation of GRB011211
  23. GRB 011211 Optical Observations: Likely Afterglow
  24. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  25. GRB 011130: Optical Observations of Chandra Sources
  26. GRB 011130: Optical Observations of Chandra sources
  27. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  28. GRB 011130: Magellan spectroscopy
  29. GRB011130, optical observations
  30. GRB011130, optical observations
  31. GRB011130 (=XRF011130): Second Revised Localization by HETE
  32. GRB 011130 I-band Observation
  33. GRB011130 (XRF011130) optical observations
  34. GRB011130 (XRF011130) SDSS PT i-band observations
  35. XRF011130: Infrared Observations
  36. GRB011130, Radio Observations
  37. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  38. GRB011130 (=XRF011130), Optical Observations
  39. XRF011130: NEAT Optical Observations
  40. GRB011130 (=XRF011130): Revised Localization of an X-ray
  41. GRB001109, Radio Monitoring
  42. GRB 011121: Errata URL
  43. GRB 011121
  44. GRB 011121: J-band observations
  45. GRB 011121: NIR observations, host galaxy?
  46. GRB010921 - Milagro GeV/TeV Observations
  47. GRB 011121: HST Scheduled
  48. GRB011121: fainter still
  49. Correction: GCN1157 (GRB 011121)
  50. GRB011121: UBRI Observations
  51. GRB011121
  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. GRB011121: fading behavior
  58. GRB011121: possible optical counterpart
  59. IPN triangulation of GRB011121
  60. GRB 011030: TNG K-band observation
  61. XRF011030: J and K band observations
  62. XRF011030: Chandra Observations
  63. GRB 011030: K-band observations
  64. GRB011030: Z-band observations
  65. GRB 011030 I-band Observation
  66. The X-ray Flash 011030 ('GRB 011030')
  67. The Radio Afterglow from the X-ray Rich GRB 011030
  68. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  69. GRB 000131: HST Detection of the Host Galaxy
  70. GRB 011019 optical observation
  71. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  72. GRB011019: Subaru Optical Observations
  73. GRB 011030 I-band Observations
  74. GRB 011030 K-band Observations
  75. GRB010921, optical observations
  76. GRB 011030, WSRT radio observations
  77. GRB011030 - further refinement WFC position
  78. GRB 011030, Radio observations
  79. GRB011030: radio search
  80. GRB 011030, R-band observations
  81. BeppoSAX ALERT: Possible X-ray rich GRB011030
  82. GRB 010921: Possible supernova component
  83. GRB011019: ROTSE-III optical observations
  84. GRB 010921, I-band observations
  85. GRB011019: Optical observations
  86. GRB011019, optical observations -- correction
  87. GRB011019, optical observations
  88. GRB010921: Spectroscopy of the Host Galaxy
  89. GRB 010921: The afterglow of HETE #1761
  90. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  91. GRB010923 as seen by BeppoSAX GRBM
  92. GRB010928(=H1770): Localization of a Long GRB by HETE
  93. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  94. GRB010921, negative optical observations
  95. GRB010921 field photometry
  96. GRB 010921 DPOSS Images Available
  97. IPN triangulation of GRB010921 (=H1761)
  98. H1761: A Bright GRB Detected by HETE
  99. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  100. GRB001109, Host Galaxy Astrometry

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