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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"

43604 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. GRB000408: Optical CCD Observations from MIRO
  7. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  8. GRB000408 [IPN Position]
  9. GRB000326 Optical Observations
  10. GRB000301C - Addendum to GCN 623
  11. GRB000301C - R magnitude lower limit
  12. GRB000326, Further VLA observations
  13. GRB 000323, optical observations
  14. GRB 000326: Optical Observations
  15. GRB000326, Radio observations
  16. GRB000326 [IPN Position]
  17. GRB 000307 optical observations
  18. GRB000323 [IPN Position]
  19. Single error box for GRB000315
  20. GRB000315 [IPN Positions]
  21. GRB000313, Radio observations
  22. GRB 000313 - optical transient in the BATSE error box
  23. GRB000301C - B and R photometry
  24. GRB000301C - R photometry
  25. GRB 000307, Optical Observations
  26. GRB 000307, BVRI Field Photometry
  27. GRB 000301C: Optical Spectrum and Redshift
  28. GRB 000301C: Optical Spectrum and Redshift
  29. GRB 000301C: A Precise Redshift Determination
  30. GRB 000301C, Optical Observation
  31. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  32. GRB 000301C: HST/STIS CCD Imaging of the field
  33. IPN error box for GRB000307
  34. GRB 000301c: K' observations
  35. GRB000301C, optical R-band observations
  36. GRB000301c - R photometry and nearby faint source confirmation
  37. GRB 000301C, Optical Observation
  38. GRB 000301c: K' observations
  39. GRB 000301C Optical Observations
  40. GRB 000301C: K' Observations
  41. GRB000301C OT candidate optical observations
  42. GRB000301C - Host galaxy not detected in R (?)
  43. Optical observations of GRB000301c
  44. GRB000301C, Radio observations
  45. GRB000301C, Radio observations
  46. GRB000301C optical observations
  47. GRB000301C, near-infrared observations (JHK' imaging)
  48. GRB 000301c near-IR observations
  49. GRB 000301C, Optical Color
  50. GRB000301C, Optical Spectroscopy
  51. GRB 000301C, UBVRI field photometry
  52. GRB 000301C, Optical Observation
  53. GRB000301C, optical observations
  54. GRB000301C 250 GHz detection
  55. GRB 000301C R-band observation
  56. GRB 000301C, Optical Observation
  57. GRB000301C, near-infrared observations (JHK' photometry)
  58. GRB 000301C: OT confirmed
  59. GRB000301c optical observations
  60. GRB 000301A, Radio Observations
  61. GRB000301C, optical observations
  62. GRB000301c, near-infrared observations
  63. GRB000301C
  64. GRB 000301C : Optical Candidate
  65. Radio observations of the error box of GRB000301A
  66. GRB000301C: RXTE/ASM and IPN localizations
  67. GRB000226 [IPN Position]
  68. HST Observations of GRB 990712
  69. GRB 000214 near-IR observations
  70. GRB 000115 Optical observations
  71. GRB 000214, Radio Observations
  72. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  73. GRB000210, Radio Observations
  74. GRB 000115, BVRI field photometry
  75. GRB000214: BeppoSAX GRBM and WFC Detection
  76. IPN annulus for GRB000214
  77. Optical observations of GRB000210
  78. GRB000210 X-ray afterglow
  79. GRB000214: X-ray afterglow candidate
  80. GRB000214 refined BeppoSAX-WFC position
  81. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  82. GRB 000210: BATSE Observations
  83. Correction to Chandra Position of GRB000210 afterglow
  84. Optical observations of the Chandra X-ray source for GRB000210
  85. GRB000210, Radio Observations
  86. Optical candidate for GRB000210
  87. Chandra Observations of GRB000210 X-ray Afterglow
  88. IPN triangulation of GRB000210
  89. GRB000210: possible afterglow detection with BeppoSAX NFI
  90. GRB000201, Radio Observations
  91. GRB000210: BeppoSAX GRBM and WFC Detection
  92. Optical observations of GRB000131
  93. GRB000201 Optical Observations
  94. GRB 000201: TAROT optical observations
  95. GRB 000131 Optical Observations
  96. GRB000126 Optical Observations
  97. BATSE GRB trigger criteria changed
  98. GRB 991208, radio observations
  99. BATSE+IPN location of GRB000131
  100. IPN localization of GRB000131

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