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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"

28066 results found.

  1. GRB 011211, spectrum and optical photometry
  2. GRB 011211: Evidence for an Optical Break
  3. GRB 011211: TNG Spectroscopic Observations
  4. optical follow-up of GRB(XRF) 011211
  5. GRB 011212: optical observation at Oslo (relayed)
  6. GRB 011211, Optical Observations
  7. GRB011212: Optical observations
  8. GRB 011211: BVRi-band photometry
  9. GRB 011211 Optical Observations: Likely Afterglow
  10. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  11. GRB 011130: Magellan spectroscopy
  12. Sub-mm and Centimeter Detections of the Host Galaxy of GRB000418
  13. GRB011130, optical observations
  14. GRB 011130, K band observations
  15. GRB011130, optical observations
  16. Detection of the X-ray afterglow of GRB011121 by BeppoSAX
  17. GRB011130 (=XRF011130): Revised Localization of an X-ray
  18. GRB001109, Radio Monitoring
  19. GRB 011121
  20. GRB 011121: J-band observations
  21. GRB 011121: NIR observations, host galaxy?
  22. GRB010921 - Milagro GeV/TeV Observations
  23. GRB 011121: HST Scheduled
  24. GRB011121: fainter still
  25. GRB 011121: Radio Observations
  26. GRB011121: continued decay
  27. GRB 011121: Detection of Bright IR Counterpart
  28. GRB011121: possible redshift, continued decay
  29. GRB011121: fading behavior
  30. GRB011121: possible optical counterpart
  31. GRB 011030 I-band Observation
  32. The X-ray Flash 011030 ('GRB 011030')
  33. The Radio Afterglow from the X-ray Rich GRB 011030
  34. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  35. GRB 000131: HST Detection of the Host Galaxy
  36. GRB010921, optical observation
  37. GRB 011030 I-band Observations
  38. GRB 011030 K-band Observations
  39. GRB 010921: Possible supernova component
  40. GRB011019: ROTSE-III optical observations
  41. GRB010921, optical observation at early time
  42. GRB010921: Spectroscopy of the Host Galaxy
  43. GRB 010921: The afterglow of HETE #1761
  44. GRB010928(=H1770): Localization of a Long GRB by HETE
  45. GRB010921, negative optical observations
  46. GRB010921 field photometry
  47. BeppoSAX/GRBM detection of GRB 010801
  48. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  49. BeppoSAX/GRBM detection of GRB010728
  50. GRB 010222 - WHT BVRI images
  51. GRB 010629 Optical Observations
  52. SGR1900+14: High Fluence Burst Localized by HETE
  53. GRB010629: A Burst Localized by HETE
  54. SGR1900+14: Second Burst Localized by HETE
  55. SGR1900+14: A Burst Localized by HETE
  56. IPN detection of SGR1900+14
  57. SGR1806-20: A Second, Intense Burst Localized by HETE
  58. SGR1806-20: Localization by HETE
  59. GRB000301C: Late-time HST/STIS observation
  60. GRB010518: a faint BeppoSAX detection
  61. GRB000418: HST/STIS Second-epoch Observations
  62. SGR 1900+14: No evidence of extended X-ray emission
  63. GRB 010222 /corrections to VBT data
  64. SGR 1900+14: Detection of extended X-ray emission
  65. GRB010412, field photometry
  66. GRB 980326: Late-time HST/STIS observations
  67. Further Optical Observations of GRB 010324
  68. GRB010222, late-time optical observation
  69. Congratulate Scott on the 1000th GRB Coordinates Network Circular!
  70. GRB010222: Chandra X-ray Observatory Observation
  71. GRB 010222, Optical Observations
  72. GRB 010222: High-Resolution Keck Spectroscopy
  73. GRB 010214, I-band data
  74. Sub-millimeter Excess/GRB 010222
  75. GRB 010222 HST/Chandra TOO
  76. GRB010222: R-band data
  77. GRB010222, possible increase of optical decay slope
  78. GRB 010222 Kyoto optical observation
  79. GRB010222: fading behavior
  80. GRB 010220: Near-IR Observations
  81. GRB010214 follow-up from Hanle
  82. GRB010222: Another absorption line system
  83. GRB010222: Optical decay slope
  84. GRB010222: Sub-millimeter detection
  85. GRB010222: R-band fading behavior
  86. GRB010222: Optical Observations
  87. GRB010222: possible optical counterpart
  88. GRB010220, Radio and Optical Observations
  89. GRB010214, candidate optical afterglow
  90. GRB 010214: X-Ray afterglow
  91. GRB010213, Radio Observations
  92. GRB010213 Optical Observation
  93. GRB010213, Radio Observations
  94. J-Band Observation of GRB 010214.
  95. GRB010214 Optical Observation
  96. GRB010214: BeppoSAX/NFI Observations
  97. GRB 010214, optical observations
  98. IPN Status Report
  99. HETE Status
  100. GRB010126 opt. obs.

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