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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"

23572 results found.

  1. GRB000519, BVRI field photometry
  2. IPN triangulation of GRB000519
  3. IPN triangulation of GRB000516
  4. Re: GRB000508B : Optical observations
  5. GRB 000418, Optical observation
  6. GRB000508B, optical photometry
  7. GRB000508B, BVR field photometry
  8. Possible GRB-related phenomenon
  9. RXTE/ASM and IPN localization of GRB 000508B
  10. GRB000424, UBVRI field photometry
  11. GRB 000424 Optical Observations
  12. GRB000418, UBVRI field photometry update
  13. The redshift of GRB 000418
  14. GRB 000429, optical observation
  15. GRB 000429, UBVRI field photometry
  16. IPN localization of GRB000429
  17. GRB 000418, UBVRI field photometry
  18. GRB000418, K'-band photometry
  19. GRB 000418, Optical Observation
  20. GRB 000418, optical observation
  21. GRB000424 Optical Observations
  22. GRB 000418, Optical Observation
  23. GRB000424, optical observations
  24. GRB 000424, Optical Observations
  25. GRB000418, near-infrared observations
  26. Correction to IPN error box for GRB000419
  27. IPN error box for GRB000418
  28. GRB000419 [IPN Position]
  29. GRB000416 Optical Observations
  30. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  31. GRB000416 BRJK observations
  32. Refined IPN error box for GRB000408
  33. GRB 991208, UBVRI field photometry
  34. GRB000408: Optical CCD Observations from MIRO
  35. GRB000408, lotis optical observations
  36. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  37. GRB000408 [IPN Position]
  38. GRB000326 Optical Observations
  39. GRB000301C - R magnitude lower limit
  40. GRB 000323, optical observations
  41. GRB000326, Radio observations
  42. GRB000326 [IPN Position]
  43. GRB 000307 optical observations
  44. GRB000323 [IPN Position]
  45. Single error box for GRB000315
  46. GRB000315 [IPN Positions]
  47. GRB 000313 - optical transient in the BATSE error box
  48. GRB000301C - B and R photometry
  49. GRB000301C - R photometry
  50. GRB 000307, BVRI Field Photometry
  51. GRB 000301C: Optical Spectrum and Redshift
  52. GRB 000301C: Optical Spectrum and Redshift
  53. GRB 000301C: A Precise Redshift Determination
  54. IPN error box for GRB000307
  55. GRB 000301c: K' observations
  56. GRB000301C, optical R-band observations
  57. GRB000301c - R photometry and nearby faint source confirmation
  58. GRB 000301c: K' observations
  59. GRB 000301C: K' Observations
  60. GRB000301C OT candidate optical observations
  61. GRB000301C - Host galaxy not detected in R (?)
  62. GRB000301C optical observations
  63. GRB000301C, near-infrared observations (JHK' imaging)
  64. GRB000301C, Optical Spectroscopy
  65. GRB 000301C, UBVRI field photometry
  66. GRB000301C 250 GHz detection
  67. GRB 000301C R-band observation
  68. GRB000301c optical observations
  69. GRB000301C, optical observations
  70. GRB000301c, near-infrared observations
  71. Radio observations of the error box of GRB000301A
  72. GRB000301A [IPN Position]
  73. GRB000226 [IPN Position]
  74. GRB 000115 Optical observations
  75. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  76. GRB 000115, BVRI field photometry
  77. GRB000214: BeppoSAX GRBM and WFC Detection
  78. IPN annulus for GRB000214
  79. GRB000210 X-ray afterglow
  80. GRB 000210: BATSE Observations
  81. Optical observations of the Chandra X-ray source for GRB000210
  82. Optical candidate for GRB000210
  83. IPN triangulation of GRB000210
  84. GRB000210: BeppoSAX GRBM and WFC Detection
  85. GRB 000201: TAROT optical observations
  86. GRB 000131 Optical Observations
  87. GRB 991208, radio observations
  88. BATSE+IPN location of GRB000131
  89. IPN localization of GRB000131
  90. GRB 000126, optical observations
  91. BATSE location of GRB000126
  92. IPN localization of GRB000126
  93. GRB 000115 Optical observations
  94. BATSE Observations of GRB000115
  95. IPN annulus for GRB000115
  96. GRB991216, UBVRIJHK field photometry
  97. GRB991216 late optical observation
  98. Single IPN error box for GRB991229
  99. BEPPOSAX GRBM Localization of GRB991226
  100. IPN error boxes for GRB991229

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Download all Circulars as a .tar.gz archive (updated once a day):
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