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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"

17373 results found.

  1. GRB000424, optical observations
  2. GRB 000429, optical observation
  3. GRB 000429, UBVRI field photometry
  4. GRB 000418, UBVRI field photometry
  5. GRB 000418, optical observation
  6. GRB 000418, Optical Observation
  7. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  8. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  9. Budget cuts in BeppoSAX operations: impact on GRB observations
  10. GRB 000408, optical observations
  11. Refined IPN error box for GRB000408
  12. GRB 991208, UBVRI field photometry
  13. GRB000408, lotis optical observations
  14. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  15. GRB000326 Optical Observations
  16. GRB000301C - Addendum to GCN 623
  17. GRB 000326: Optical Observations
  18. GRB000326, Radio observations
  19. GRB000326 [IPN Position]
  20. GRB000313, Radio observations
  21. GRB 000313 - optical transient in the BATSE error box
  22. GRB 000307, BVRI Field Photometry
  23. GRB 000301C: HST/STIS CCD Imaging of the field
  24. IPN error box for GRB000307
  25. GRB000301C, optical R-band observations
  26. GRB 000301C Optical Observations
  27. GRB 000301C: K' Observations
  28. GRB000301C - Host galaxy not detected in R (?)
  29. Optical observations of GRB000301c
  30. GRB000301C, Radio observations
  31. GRB000301C, Radio observations
  32. GRB 000301c near-IR observations
  33. GRB 000301C, UBVRI field photometry
  34. GRB000301C, near-infrared observations (JHK' photometry)
  35. GRB 000301C: OT confirmed
  36. GRB000301c optical observations
  37. GRB000301C
  38. GRB 000301C : Optical Candidate
  39. HST Observations of GRB 990712
  40. GRB 000214 near-IR observations
  41. GRB 000214, Radio Observations
  42. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  43. GRB000210, Radio Observations
  44. GRB 000115, BVRI field photometry
  45. GRB000214: BeppoSAX GRBM and WFC Detection
  46. Optical observations of GRB000210
  47. GRB000210 X-ray afterglow
  48. GRB000214: X-ray afterglow candidate
  49. GRB000214 refined BeppoSAX-WFC position
  50. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  51. Correction to Chandra Position of GRB000210 afterglow
  52. Optical observations of the Chandra X-ray source for GRB000210
  53. GRB000210, Radio Observations
  54. GRB000210: possible afterglow detection with BeppoSAX NFI
  55. GRB000201, Radio Observations
  56. GRB000210: BeppoSAX GRBM and WFC Detection
  57. GRB000201 Optical Observations
  58. GRB 000126, optical observations
  59. IPN localization of GRB000126
  60. IPN annulus for GRB000115
  61. GRB991216, UBVRIJHK field photometry
  62. GCN resumes full operations
  63. GRB 991216: Detection of the Host and/or Absorber Galaxy
  64. GRB 991216 RXTE ASM Observations
  65. GRB 991217 (SAX J2303.2+0015) Optical observations
  66. Chandra observation of the X-ray afterglow of GRB991216
  67. SAX J2303.2+0015 Optical observations
  68. IR observations of GRB991216
  69. GRB 991217 (SAX J2303.2+0015) Optical observations
  70. GRB 991216 Radio Observations
  71. GRB 991208 Infrared Detection
  72. GRB991216
  73. GRB 991216--Summary of RXTE Observations
  74. GRB 991216 Optical Observations
  75. GRB 991216, optical observations
  76. GRB 991208 SAO-RAS Spectroscopy
  77. SAX J2303.2+0015: an x-ray/GRB?
  78. GRB 991216, Optical Transient
  79. GRB991216 ('Beethoven Burst') B, R, and K Observations
  80. GRB991216, infrared observations
  81. GRB 991208 optical observations
  82. GRB 991216 Optical Observation
  83. GRB 991216: Extremely bright BATSE burst
  84. R-band Observations of GRB991208 at TNG
  85. GRB991208, optical observations
  86. GRB 991208, Optical Observation
  87. GRB991208, optical observations
  88. IPN localization of GRB991208
  89. Optical Observations of GRB991105
  90. GRB991106: BeppoSAX/BATSE results
  91. BeppoSAX NFI Observation of GRB991106
  92. GRB 991106, radio observations
  93. GRB991106: the first BeppoSAX short GRB detection?
  94. GRB 991106 Optical Observations
  95. GRB991106, optical observation at SAO-RAS
  96. GRB 991106, LOTIS Optical Observations
  97. GRB991105: SAX-GRBM/-WFC detection
  98. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  99. GRB 991014, Optical Observations
  100. GRB 991014 - BeppoSAX NFI observations

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