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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"

2744 results found.

  1. GRB011121: continued decay
  2. GRB011121: possible redshift, continued decay
  3. GRB011121: fading behavior
  4. GRB011121: possible optical counterpart
  5. GRB 011030 I-band Observation
  6. GRB 011030, WSRT radio observations
  7. BeppoSAX ALERT: Possible X-ray rich GRB011030
  8. GRB 010921: Possible supernova component
  9. GRB010921: Spectroscopy of the Host Galaxy
  10. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  11. IPN triangulation of GRB010921 (=H1761)
  12. GCN and HETE status
  13. GRB010629: Optical Observations
  14. Possible burst from SGR1806-20
  15. IPN triangulation of GRB010613
  16. HETE Fully-Automated GCN Notices
  17. GRB010214, optical observations
  18. SGR1900+14
  19. Possible precursor to the SGR1900+14 giant burst
  20. Further Optical Observations of GRB 010324
  21. GRB 010222, Optical Observations
  22. Sub-millimeter Excess/GRB 010222
  23. GRB010222: R-band data
  24. GRB010222, possible increase of optical decay slope
  25. GRB010222: Optical Observations
  26. GRB010222: possible optical counterpart
  27. GRB010222
  28. GRB 010214, Optical Observations
  29. GRB010214, Radio Observations
  30. GRB010214, optical observations
  31. Possible InfraRed Transient of GRB 010214.
  32. GRB010126 optical observations
  33. IPN TRIANGULATION OF GRB010126
  34. GRB 001212 Optical Observation
  35. GRB 001212 possible OA in 2MASS
  36. GRB 001212 possible OA
  37. Confirmation of IPN position for GRB001204
  38. Optical/NIR observations of GRB001109
  39. GRB 001018, Possible Radio Afterglow
  40. HETE positions added to GCN
  41. GRB000926 - Optical observations
  42. "Snapshot" afterglow IDs and GRB 000830
  43. IPN localization of GRB000730B
  44. GRB 990510: Possible detection of a host galaxy
  45. possible optical counterpart of GRB 000630
  46. GRB990308, HST/STIS observations of the host galaxy
  47. GRB000615, further R-band photometry
  48. BeppoSAX X-ray transient/possible GRB000608
  49. GRB 000418: Detection of the Host Galaxy
  50. IPN localization and time history of GRB000528
  51. New IPN localization of GRB000529
  52. GRB000508B, optical photometry
  53. Possible GRB-related phenomenon
  54. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  55. Refined IPN error box for GRB000408
  56. GRB000408 [IPN Position]
  57. GRB000315 [IPN Positions]
  58. GRB 000301C: Optical Spectrum and Redshift
  59. GRB 000301C: Optical Spectrum and Redshift
  60. GRB 000301C: A Precise Redshift Determination
  61. IPN error box for GRB000307
  62. GRB000301C - Host galaxy not detected in R (?)
  63. GRB000301C, near-infrared observations (JHK' imaging)
  64. GRB000301C, optical observations
  65. GRB000301C, near-infrared observations (JHK' photometry)
  66. GRB 000301A, Radio Observations
  67. GRB000226 [IPN Position]
  68. IPN annulus for GRB000214
  69. Correction to Chandra Position of GRB000210 afterglow
  70. GRB000210: possible afterglow detection with BeppoSAX NFI
  71. BATSE+IPN location of GRB000131
  72. BATSE location of GRB000126
  73. IPN localization of GRB000126
  74. GRB991216 late optical observation
  75. BEPPOSAX GRBM Localization of GRB991226
  76. IPN error boxes for GRB991229
  77. IPN localization of GRB991226
  78. IPN error boxes for GRB991221
  79. IPN error box for GRB991216
  80. GRB991216 Optical and IR observations
  81. GRB 991216 Optical Observations
  82. GRB 991216, optical observations
  83. GRB991208, optical observations
  84. GRB 991106 Optical Observations
  85. GRB 991014, Optical Observations
  86. GRB990907 and 990908
  87. GRB 990806, Optical Observations
  88. GRB990806: possible X-ray afterglow, BeppoSAX
  89. GRB990705: No Evidence for Neutrino Signal
  90. BeppoSAX GRB990705: possible X-ray afterglow
  91. GRB 990704, optical observations
  92. GRB990704
  93. GRB990704
  94. GRB990704: possible X-ray afterglow
  95. Identification of a possible optical counterpart for GRB990704
  96. GRB 990510 optical observations
  97. GRB990510: NFI X-ray source
  98. GRB 990510 optical observations
  99. Refined IPN error box for GRB990506
  100. GRB 990506: Limits on the possible optical transient

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