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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"

44626 results found.

  1. GRB 020124 Optical Observations
  2. IPN triangulation of GRB020124 (HETE 1896)
  3. IPN observations of SGR1806-20
  4. GRB 020124: Optical afterglow
  5. GRB020124(=H1896): Localization of a Long GRB by HETE
  6. HETE 1896: Optical observations
  7. GRB optical counterpart candidate in GCN 1217 is M dwarf
  8. Possible optical counterpart to a GRB
  9. GRB011212, Optical Observations
  10. GRB011211: BeppoSAX/GRBM data
  11. Optical polarization observations for GRB011211
  12. GRB 011211: Detection of the Probable Host Galaxy
  13. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  14. Color indices of the afterglow of GRB011211
  15. GRB011212: Optical observations at Gunma
  16. GRB 011211, spectrum and optical photometry
  17. GRB 011130: Optical Observations of X-ray and Radio Sources
  18. GRB 011130, Radio/X-ray Comparison
  19. GRB011212: Optical observations
  20. GRB 011212: optical observation at Asiago
  21. GRB 011211: Evidence for an Optical Break
  22. GRB 011211: TNG Spectroscopic Observations
  23. optical follow-up of GRB(XRF) 011211
  24. GRB 011212: optical observation at Oslo (relayed)
  25. GRB 011211: Optical Spectroscopy
  26. GRB 011211, Optical Observations
  27. GRB011212, BVRI field photometry
  28. GRB011211, BVRI field photometry
  29. GRB011212: Optical observations
  30. GRB 011211: BVRi-band photometry
  31. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  32. Fading of the optical source associated of XRF 011211
  33. XMM-Newton observation of GRB011211
  34. GRB 011211 Optical Observations: Likely Afterglow
  35. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  36. GRB011211(=XRF011211): BeppoSAX refined positions
  37. BeppoSAX Alert: GRB011211(=XRF011211)
  38. GRB 011130: Optical Observations of Chandra Sources
  39. GRB 011130: Optical Observations of Chandra sources
  40. GRB011130 (XRF011130) Chandra Observations
  41. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  42. GRB 011130: Magellan spectroscopy
  43. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  44. GRB011130, optical observations
  45. GRB 011130, K band observations
  46. GRB011130, optical observations
  47. GRB011130 (=XRF011130): Second Revised Localization by HETE
  48. GRB 011130 I-band Observation
  49. GRB011130 (XRF011130) optical observations
  50. GRB011130 (XRF011130) SDSS PT i-band observations
  51. XRF011130: Infrared Observations
  52. GRB011130, Radio Observations
  53. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  54. GRB011130 (=XRF011130), Optical Observations
  55. XRF011130: NEAT Optical Observations
  56. GRB011130 (=XRF011130): Revised Localization of an X-ray
  57. GRB001109, Radio Monitoring
  58. GRB 011121: Errata URL
  59. GRB 011121
  60. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  61. GRB 011121: J-band observations
  62. GRB 011121: NIR observations, host galaxy?
  63. GRB010921 - Milagro GeV/TeV Observations
  64. GRB 011121: HST Scheduled
  65. GRB011121: fainter still
  66. Correction: GCN1157 (GRB 011121)
  67. GRB011121: UBRI Observations
  68. GRB011121
  69. GRB 011121: Radio Observations
  70. GRB 011121 J-Band Astrometry
  71. GRB011121: continued decay
  72. GRB 011121: Detection of Bright IR Counterpart
  73. GRB011121: possible redshift, continued decay
  74. GRB011121: fading behavior
  75. GRB011121: possible optical counterpart
  76. GRB011121: BeppoSAX-WFC refined positions
  77. IPN triangulation of GRB011121
  78. BEPPOSAX GRB011121
  79. GRB 011030: TNG K-band observation
  80. XRF011030: J and K band observations
  81. GRB011030, optical observation
  82. XRF011030: Chandra Observations
  83. GRB 011030: K-band observations
  84. GRB011030: Z-band observations
  85. GRB 011030 R band observations
  86. GRB 011030 I-band Observation
  87. The X-ray Flash 011030 ('GRB 011030')
  88. Non-triggered burst 011030 ("GRB 011030")
  89. The Radio Afterglow from the X-ray Rich GRB 011030
  90. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  91. GRB 970828: HST Observations of the Host Galaxy
  92. GRB 000131: HST Detection of the Host Galaxy
  93. GRB 970828: HST Observations of the Host Galaxy
  94. GRB010921, optical observation
  95. GRB 011019 optical observation
  96. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  97. GRB011019: Subaru Optical Observations
  98. GRB 011030 I-band Observations
  99. GRB 011030 K-band Observations
  100. GRB010921, optical observations

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