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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"

36143 results found.

  1. IPN triangulation of GRB000519
  2. IPN triangulation of GRB000516
  3. Re: GRB000508B : Optical observations
  4. GRB 000418, Optical observation
  5. GRB000508B, optical photometry
  6. GRB000508B, BVR field photometry
  7. Possible GRB-related phenomenon
  8. RXTE/ASM and IPN localization of GRB 000508B
  9. GRB000424, UBVRI field photometry
  10. GRB 000424 Optical Observations
  11. GRB000418, UBVRI field photometry update
  12. The redshift of GRB 000418
  13. GRB 000429, optical observation
  14. GRB 000429, UBVRI field photometry
  15. IPN localization of GRB000429
  16. GRB 000418, UBVRI field photometry
  17. GRB000418, K'-band photometry
  18. GRB 000418, Optical Observation
  19. GRB 000418, optical observation
  20. GRB000424 Optical Observations
  21. GRB 000418, Optical Observation
  22. GRB 000424, Optical Observations
  23. GRB 000418, Optical Observation
  24. GRB000418, near-infrared observations
  25. Correction to IPN error box for GRB000419
  26. IPN error box for GRB000418
  27. GRB000419 [IPN Position]
  28. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  29. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  30. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  31. Budget cuts in BeppoSAX operations: impact on GRB observations
  32. GRB 000408, optical observations
  33. Refined IPN error box for GRB000408
  34. GRB 991208, UBVRI field photometry
  35. GRB000301c results
  36. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  37. GRB000408 [IPN Position]
  38. GRB000326 Optical Observations
  39. GRB000301C - Addendum to GCN 623
  40. GRB000301C - R magnitude lower limit
  41. GRB 000323, optical observations
  42. GRB 000326: Optical Observations
  43. GRB000326, Radio observations
  44. GRB000326 [IPN Position]
  45. GRB 000307 optical observations
  46. GRB000323 [IPN Position]
  47. GRB000315 [IPN Positions]
  48. GRB 000313 - optical transient in the BATSE error box
  49. GRB000301C - B and R photometry
  50. GRB000301C - R photometry
  51. GRB 000307, Optical Observations
  52. GRB 000307, BVRI Field Photometry
  53. GRB 000301C: Optical Spectrum and Redshift
  54. GRB 000301C: Optical Spectrum and Redshift
  55. GRB 000301C: A Precise Redshift Determination
  56. GRB 000301C, Optical Observation
  57. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  58. GRB 000301C: HST/STIS CCD Imaging of the field
  59. IPN error box for GRB000307
  60. GRB 000301c: K' observations
  61. GRB000301C, optical R-band observations
  62. GRB000301c - R photometry and nearby faint source confirmation
  63. GRB 000301C, Optical Observation
  64. GRB 000301c: K' observations
  65. GRB 000301C Optical Observations
  66. GRB 000301C: K' Observations
  67. GRB000301C - Host galaxy not detected in R (?)
  68. Optical observations of GRB000301c
  69. GRB000301C optical observations
  70. GRB 000301c near-IR observations
  71. GRB 000301C, Optical Color
  72. GRB000301C, Optical Spectroscopy
  73. GRB 000301C, UBVRI field photometry
  74. GRB 000301C, Optical Observation
  75. GRB000301C 250 GHz detection
  76. GRB 000301C R-band observation
  77. GRB 000301C, Optical Observation
  78. GRB000301C, near-infrared observations (JHK' photometry)
  79. GRB 000301C: OT confirmed
  80. GRB000301c optical observations
  81. GRB 000301A, Radio Observations
  82. GRB000301C, optical observations
  83. GRB000301c, near-infrared observations
  84. GRB000301C
  85. GRB 000301C : Optical Candidate
  86. GRB000301C: RXTE/ASM and IPN localizations
  87. GRB000226 [IPN Position]
  88. HST Observations of GRB 990712
  89. GRB 000214 near-IR observations
  90. GRB 000115 Optical observations
  91. GRB 000214, Radio Observations
  92. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  93. GRB 000115, BVRI field photometry
  94. IPN annulus for GRB000214
  95. BATSE GRB trigger criterion changed
  96. GRB000210 X-ray afterglow
  97. GRB000214: X-ray afterglow candidate
  98. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  99. GRB 000210: BATSE Observations
  100. Optical observations of the Chandra X-ray source for GRB000210

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