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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"

27549 results found.

  1. GRB001109, Radio Monitoring
  2. GRB 011121
  3. GRB 011121: J-band observations
  4. GRB 011121: NIR observations, host galaxy?
  5. GRB010921 - Milagro GeV/TeV Observations
  6. GRB 011121: HST Scheduled
  7. GRB011121: fainter still
  8. GRB 011121: Radio Observations
  9. GRB011121: continued decay
  10. GRB 011121: Detection of Bright IR Counterpart
  11. GRB011121: possible redshift, continued decay
  12. GRB011121: fading behavior
  13. GRB011121: possible optical counterpart
  14. GRB 011030 I-band Observation
  15. The X-ray Flash 011030 ('GRB 011030')
  16. The Radio Afterglow from the X-ray Rich GRB 011030
  17. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  18. GRB 000131: HST Detection of the Host Galaxy
  19. GRB010921, optical observation
  20. GRB 011030 I-band Observations
  21. GRB 011030 K-band Observations
  22. GRB 010921: Possible supernova component
  23. GRB011019: ROTSE-III optical observations
  24. GRB010921, optical observation at early time
  25. GRB010921: Spectroscopy of the Host Galaxy
  26. GRB 010921: The afterglow of HETE #1761
  27. GRB010928(=H1770): Localization of a Long GRB by HETE
  28. GRB010921, negative optical observations
  29. GRB010921 field photometry
  30. BeppoSAX/GRBM detection of GRB 010801
  31. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  32. BeppoSAX/GRBM detection of GRB010728
  33. GRB 010222 - WHT BVRI images
  34. GRB 010629 Optical Observations
  35. SGR1900+14: High Fluence Burst Localized by HETE
  36. GRB010629: A Burst Localized by HETE
  37. SGR1900+14: Second Burst Localized by HETE
  38. SGR1900+14: A Burst Localized by HETE
  39. IPN detection of SGR1900+14
  40. SGR1806-20: A Second, Intense Burst Localized by HETE
  41. SGR1806-20: Localization by HETE
  42. GRB000301C: Late-time HST/STIS observation
  43. GRB010518: a faint BeppoSAX detection
  44. GRB000418: HST/STIS Second-epoch Observations
  45. SGR 1900+14: No evidence of extended X-ray emission
  46. GRB 010222 /corrections to VBT data
  47. SGR 1900+14: Detection of extended X-ray emission
  48. GRB010412, field photometry
  49. GRB 980326: Late-time HST/STIS observations
  50. Further Optical Observations of GRB 010324
  51. GRB010222, late-time optical observation
  52. Congratulate Scott on the 1000th GRB Coordinates Network Circular!
  53. GRB010222: Chandra X-ray Observatory Observation
  54. GRB 010222, Optical Observations
  55. GRB 010222: High-Resolution Keck Spectroscopy
  56. GRB 010214, I-band data
  57. Sub-millimeter Excess/GRB 010222
  58. GRB 010222 HST/Chandra TOO
  59. GRB010222: R-band data
  60. GRB010222, possible increase of optical decay slope
  61. GRB 010222 Kyoto optical observation
  62. GRB010222: fading behavior
  63. GRB 010220: Near-IR Observations
  64. GRB010214 follow-up from Hanle
  65. GRB010222: Another absorption line system
  66. GRB010222: Optical decay slope
  67. GRB010222: Sub-millimeter detection
  68. GRB010222: R-band fading behavior
  69. GRB010222: Optical Observations
  70. GRB010222: possible optical counterpart
  71. GRB010220, Radio and Optical Observations
  72. GRB010214, candidate optical afterglow
  73. GRB 010214: X-Ray afterglow
  74. GRB010213, Radio Observations
  75. GRB010213 Optical Observation
  76. GRB010213, Radio Observations
  77. J-Band Observation of GRB 010214.
  78. GRB010214 Optical Observation
  79. GRB010214: BeppoSAX/NFI Observations
  80. GRB 010214, optical observations
  81. IPN Status Report
  82. HETE Status
  83. GRB010126 opt. obs.
  84. GRB010126: CONCAM crude optical limits during GRB
  85. GRB010126 optical observations
  86. Optical Observations of GRB 001018 at Keck
  87. Optical observations of GRB 001018 with JCAM
  88. GRB 001212 Optical Observation
  89. GRB 001212 Optical Observation
  90. Confirmation of IPN position for GRB001204
  91. GRB001120: Gunn-i observations
  92. WSRT 4.8 GHz observations of GRB001109
  93. Optical/NIR observations of GRB001109
  94. GRB 001109: deep JHK upper limits
  95. GRB 001109 X-ray afterglow with BeppoSAX
  96. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  97. GRB001007: Optical observations
  98. GRB001007, Radio observations
  99. GRB 001018, Possible Radio Afterglow
  100. GRB 000926: Improved Absorber Redshift

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