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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"

41624 results found.

  1. Optical polarization observations for GRB011211
  2. GRB 011211: Detection of the Probable Host Galaxy
  3. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  4. GRB011212: Optical observations at Gunma
  5. GRB 011211, spectrum and optical photometry
  6. GRB 011130: Optical Observations of X-ray and Radio Sources
  7. GRB 011130, Radio/X-ray Comparison
  8. GRB011212: Optical observations
  9. GRB 011212: optical observation at Asiago
  10. GRB 011211: Evidence for an Optical Break
  11. GRB 011211: TNG Spectroscopic Observations
  12. GRB 011212: optical observation at Oslo (relayed)
  13. GRB 011211, Optical Observations
  14. GRB011212, BVRI field photometry
  15. GRB011211, BVRI field photometry
  16. GRB011212: Optical observations
  17. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  18. Fading of the optical source associated of XRF 011211
  19. XMM-Newton observation of GRB011211
  20. GRB 011211 Optical Observations: Likely Afterglow
  21. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  22. GRB 011130: Optical Observations of Chandra Sources
  23. GRB 011130: Optical Observations of Chandra sources
  24. GRB011130 (XRF011130) Chandra Observations
  25. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  26. GRB 011130: Magellan spectroscopy
  27. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  28. GRB011130, optical observations
  29. GRB 011130, K band 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
  43. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  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. GRB011121: UBRI Observations
  50. GRB011121
  51. GRB 011121: Radio Observations
  52. GRB011121: continued decay
  53. GRB 011121: Detection of Bright IR Counterpart
  54. GRB011121: possible redshift, continued decay
  55. GRB011121: fading behavior
  56. GRB011121: possible optical counterpart
  57. GRB 011030: TNG K-band observation
  58. XRF011030: J and K band observations
  59. GRB011030, optical observation
  60. XRF011030: Chandra Observations
  61. GRB 011030: K-band observations
  62. GRB011030: Z-band observations
  63. GRB 011030 R band observations
  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. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  74. GRB011019: Subaru Optical Observations
  75. GRB 011030 I-band Observations
  76. GRB 011030 K-band Observations
  77. GRB010921, optical observations
  78. GRB 011030, WSRT radio observations
  79. GRB011030 - further refinement WFC position
  80. GRB 011030, Radio observations
  81. GRB 011030, R-band observations
  82. GRB 010921: Possible supernova component
  83. GRB011019: NEAT Optical Observations
  84. GRB011019: ROTSE-III optical observations
  85. GRB 010921, I-band observations
  86. GRB011019: Optical observations
  87. GRB011019, optical observations -- correction
  88. GRB011019, optical observations
  89. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  90. GRB010921: Spectroscopy of the Host Galaxy
  91. GRB 010921: The afterglow of HETE #1761
  92. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  93. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  94. GRB010923 as seen by BeppoSAX GRBM
  95. GRB010928(=H1770): Localization of a Long GRB by HETE
  96. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  97. GRB010921, negative optical observations
  98. GRB010921 field photometry
  99. GRB010921 Optical Observations
  100. GRB 010921 DPOSS Images Available

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