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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"

32813 results found.

  1. Budget cuts in BeppoSAX operations: impact on GRB observations
  2. GRB 000408, optical observations
  3. Refined IPN error box for GRB000408
  4. GRB 991208, UBVRI field photometry
  5. GRB000301c results
  6. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  7. GRB000408 [IPN Position]
  8. GRB000326 Optical Observations
  9. GRB000301C - Addendum to GCN 623
  10. GRB000301C - R magnitude lower limit
  11. GRB 000323, optical observations
  12. GRB 000326: Optical Observations
  13. GRB000326, Radio observations
  14. GRB000326 [IPN Position]
  15. GRB 000307 optical observations
  16. GRB000323 [IPN Position]
  17. GRB000315 [IPN Positions]
  18. GRB 000313 - optical transient in the BATSE error box
  19. GRB000301C - B and R photometry
  20. GRB000301C - R photometry
  21. GRB 000307, Optical Observations
  22. GRB 000307, BVRI Field Photometry
  23. GRB 000301C: Optical Spectrum and Redshift
  24. GRB 000301C: Optical Spectrum and Redshift
  25. GRB 000301C: A Precise Redshift Determination
  26. GRB 000301C, Optical Observation
  27. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  28. GRB 000301C: HST/STIS CCD Imaging of the field
  29. IPN error box for GRB000307
  30. GRB 000301c: K' observations
  31. GRB000301C, optical R-band observations
  32. GRB000301c - R photometry and nearby faint source confirmation
  33. GRB 000301C, Optical Observation
  34. GRB 000301c: K' observations
  35. GRB 000301C Optical Observations
  36. GRB 000301C: K' Observations
  37. GRB000301C - Host galaxy not detected in R (?)
  38. Optical observations of GRB000301c
  39. GRB000301C optical observations
  40. GRB 000301c near-IR observations
  41. GRB 000301C, Optical Color
  42. GRB000301C, Optical Spectroscopy
  43. GRB 000301C, UBVRI field photometry
  44. GRB 000301C, Optical Observation
  45. GRB000301C 250 GHz detection
  46. GRB 000301C R-band observation
  47. GRB 000301C, Optical Observation
  48. GRB000301C, near-infrared observations (JHK' photometry)
  49. GRB 000301C: OT confirmed
  50. GRB000301c optical observations
  51. GRB 000301A, Radio Observations
  52. GRB000301C, optical observations
  53. GRB000301c, near-infrared observations
  54. GRB000301C
  55. GRB 000301C : Optical Candidate
  56. GRB000301C: RXTE/ASM and IPN localizations
  57. GRB000226 [IPN Position]
  58. HST Observations of GRB 990712
  59. GRB 000214 near-IR observations
  60. GRB 000115 Optical observations
  61. GRB 000214, Radio Observations
  62. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  63. GRB 000115, BVRI field photometry
  64. IPN annulus for GRB000214
  65. BATSE GRB trigger criterion changed
  66. GRB000210 X-ray afterglow
  67. GRB000214: X-ray afterglow candidate
  68. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  69. GRB 000210: BATSE Observations
  70. Optical observations of the Chandra X-ray source for GRB000210
  71. Chandra Observations of GRB000210 X-ray Afterglow
  72. IPN triangulation of GRB000210
  73. GRB 000201: TAROT optical observations
  74. GRB 000131 Optical Observations
  75. GRB000126 Optical Observations
  76. BATSE GRB trigger criteria changed
  77. GRB 991208, radio observations
  78. BATSE+IPN location of GRB000131
  79. IPN localization of GRB000131
  80. GRB 000126, optical observations
  81. GRB000126, optical observations
  82. BATSE location of GRB000126
  83. IPN localization of GRB000126
  84. GRB 000115 Optical observations
  85. BATSE Observations of GRB000115
  86. Second RXTE Observation of GRB 000115
  87. GRB991216, UBVRIJHK field photometry
  88. Single IPN error box for GRB991229
  89. GCN resumes full operations
  90. GRB 991216 VLBA Observations
  91. BEPPOSAX GRBM Localization of GRB991226
  92. IPN error boxes for GRB991229
  93. GRB 991216: J band spectrophotometry
  94. GRB 991216: Detection of the Host and/or Absorber Galaxy
  95. IPN localization of GRB991226
  96. Single IPN error box for GRB991221
  97. IPN error boxes for GRB991221
  98. GRB 991216 RXTE ASM Observations
  99. IPN error box for GRB991216
  100. GRB 991216: Updated BATSE parameters

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