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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"
  1. BeppoSAX GRB000424
  2. Correction to IPN error box for GRB000419
  3. IPN error box for GRB000418
  4. GRB000419 [IPN Position]
  5. GRB000416 Optical Observations
  6. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  7. GRB000416 BRJK observations
  8. 1SAXJ1715.0-7134 refined position
  9. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  10. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  11. Budget cuts in BeppoSAX operations: impact on GRB observations
  12. GRB 000408, optical observations
  13. Refined IPN error box for GRB000408
  14. GRB 991208, UBVRI field photometry
  15. GRB000301c results
  16. GRB000408: Optical CCD Observations from MIRO
  17. GRB000408, lotis optical observations
  18. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  19. GRB000408 [IPN Position]
  20. GRB000326 Optical Observations
  21. GRB000301C - Addendum to GCN 623
  22. GRB000301C - R magnitude lower limit
  23. GRB000326, Further VLA observations
  24. GRB 000323, optical observations
  25. GRB 000326: Optical Observations
  26. GRB000326, Radio observations
  27. GRB000326 [IPN Position]
  28. GRB 000307 optical observations
  29. GRB000323 [IPN Position]
  30. Single error box for GRB000315
  31. GRB000315 [IPN Positions]
  32. GRB000313, Radio observations
  33. GRB 000313 - optical transient in the BATSE error box
  34. GRB000301C - B and R photometry
  35. GRB000301C - R photometry
  36. GRB 000307, Optical Observations
  37. GRB 000307, BVRI Field Photometry
  38. GRB 000301C: Optical Spectrum and Redshift
  39. GRB 000301C: Optical Spectrum and Redshift
  40. GRB 000301C: A Precise Redshift Determination
  41. GRB 000301C, Optical Observation
  42. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  43. GRB 000301C: HST/STIS CCD Imaging of the field
  44. IPN error box for GRB000307
  45. GRB 000301c: K' observations
  46. GRB000301C, optical R-band observations
  47. GRB000301c - R photometry and nearby faint source confirmation
  48. GRB 000301C, Optical Observation
  49. GRB 000301c: K' observations
  50. GRB 000301C Optical Observations
  51. GRB 000301C: K' Observations
  52. GRB000301C OT candidate optical observations
  53. GRB000301C - Host galaxy not detected in R (?)
  54. Optical observations of GRB000301c
  55. GRB000301C, Radio observations
  56. GRB000301C, Radio observations
  57. GRB000301C optical observations
  58. GRB000301C, near-infrared observations (JHK' imaging)
  59. GRB 000301c near-IR observations
  60. GRB 000301C, Optical Color
  61. GRB000301C, Optical Spectroscopy
  62. GRB 000301C, UBVRI field photometry
  63. GRB 000301C, Optical Observation
  64. GRB000301C, optical observations
  65. GRB000301C 250 GHz detection
  66. GRB 000301C R-band observation
  67. GRB 000301C, Optical Observation
  68. GRB000301C, near-infrared observations (JHK' photometry)
  69. GRB 000301C: OT confirmed
  70. GRB000301c optical observations
  71. GRB 000301A, Radio Observations
  72. GRB000301C, optical observations
  73. GRB000301c, near-infrared observations
  74. GRB000301C
  75. GRB 000301C : Optical Candidate
  76. Radio observations of the error box of GRB000301A
  77. GRB000301C: RXTE/ASM and IPN localizations
  78. GRB000301A [IPN Position]
  79. GRB000226 [IPN Position]
  80. HST Observations of GRB 990712
  81. GRB 000214 near-IR observations
  82. GRB 000115 Optical observations
  83. GRB 000214, Radio Observations
  84. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  85. GRB000210, Radio Observations
  86. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  87. GRB 000115, BVRI field photometry
  88. GRB000214: BeppoSAX GRBM and WFC Detection
  89. IPN annulus for GRB000214
  90. BATSE GRB trigger criterion changed
  91. Optical observations of GRB000210
  92. GRB000210 X-ray afterglow
  93. GRB000214: X-ray afterglow candidate
  94. GRB000214 refined BeppoSAX-WFC position
  95. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  96. GRB 000210: BATSE Observations
  97. Correction to Chandra Position of GRB000210 afterglow
  98. Optical observations of the Chandra X-ray source for GRB000210
  99. GRB000210, Radio Observations
  100. Optical candidate for GRB000210

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