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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"

36145 results found.

  1. GRB 000528 Optical Observations
  2. GRB000519, BVRI field photometry
  3. IPN triangulation of GRB000519
  4. IPN triangulation of GRB000516
  5. Re: GRB000508B : Optical observations
  6. GRB 000418, Optical observation
  7. GRB000508B, optical photometry
  8. GRB000508B, BVR field photometry
  9. Possible GRB-related phenomenon
  10. RXTE/ASM and IPN localization of GRB 000508B
  11. GRB000424, UBVRI field photometry
  12. GRB 000424 Optical Observations
  13. GRB000418, UBVRI field photometry update
  14. The redshift of GRB 000418
  15. GRB 000429, optical observation
  16. GRB 000429, UBVRI field photometry
  17. IPN localization of GRB000429
  18. GRB 000418, UBVRI field photometry
  19. GRB000418, K'-band photometry
  20. GRB 000418, Optical Observation
  21. GRB 000418, optical observation
  22. GRB000424 Optical Observations
  23. GRB 000418, Optical Observation
  24. GRB 000424, Optical Observations
  25. GRB 000418, Optical Observation
  26. GRB000418, near-infrared observations
  27. Correction to IPN error box for GRB000419
  28. IPN error box for GRB000418
  29. GRB000419 [IPN Position]
  30. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  31. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  32. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  33. Budget cuts in BeppoSAX operations: impact on GRB observations
  34. GRB 000408, optical observations
  35. Refined IPN error box for GRB000408
  36. GRB 991208, UBVRI field photometry
  37. GRB000301c results
  38. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  39. GRB000408 [IPN Position]
  40. GRB000326 Optical Observations
  41. GRB000301C - Addendum to GCN 623
  42. GRB000301C - R magnitude lower limit
  43. GRB 000323, optical observations
  44. GRB 000326: Optical Observations
  45. GRB000326, Radio observations
  46. GRB000326 [IPN Position]
  47. GRB 000307 optical observations
  48. GRB000323 [IPN Position]
  49. GRB000315 [IPN Positions]
  50. GRB 000313 - optical transient in the BATSE error box
  51. GRB000301C - B and R photometry
  52. GRB000301C - R photometry
  53. GRB 000307, Optical Observations
  54. GRB 000307, BVRI Field Photometry
  55. GRB 000301C: Optical Spectrum and Redshift
  56. GRB 000301C: Optical Spectrum and Redshift
  57. GRB 000301C: A Precise Redshift Determination
  58. GRB 000301C, Optical Observation
  59. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  60. GRB 000301C: HST/STIS CCD Imaging of the field
  61. IPN error box for GRB000307
  62. GRB 000301c: K' observations
  63. GRB000301C, optical R-band observations
  64. GRB000301c - R photometry and nearby faint source confirmation
  65. GRB 000301C, Optical Observation
  66. GRB 000301c: K' observations
  67. GRB 000301C Optical Observations
  68. GRB 000301C: K' Observations
  69. GRB000301C - Host galaxy not detected in R (?)
  70. Optical observations of GRB000301c
  71. GRB000301C optical observations
  72. GRB 000301c near-IR observations
  73. GRB 000301C, Optical Color
  74. GRB000301C, Optical Spectroscopy
  75. GRB 000301C, UBVRI field photometry
  76. GRB 000301C, Optical Observation
  77. GRB000301C 250 GHz detection
  78. GRB 000301C R-band observation
  79. GRB 000301C, Optical Observation
  80. GRB000301C, near-infrared observations (JHK' photometry)
  81. GRB 000301C: OT confirmed
  82. GRB000301c optical observations
  83. GRB 000301A, Radio Observations
  84. GRB000301C, optical observations
  85. GRB000301c, near-infrared observations
  86. GRB000301C
  87. GRB 000301C : Optical Candidate
  88. GRB000301C: RXTE/ASM and IPN localizations
  89. GRB000226 [IPN Position]
  90. HST Observations of GRB 990712
  91. GRB 000214 near-IR observations
  92. GRB 000115 Optical observations
  93. GRB 000214, Radio Observations
  94. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  95. GRB 000115, BVRI field photometry
  96. IPN annulus for GRB000214
  97. BATSE GRB trigger criterion changed
  98. GRB000210 X-ray afterglow
  99. GRB000214: X-ray afterglow candidate
  100. BeppoSAX GRB000214 ("S. Valentine's day GRB")

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