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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"

18023 results found.

  1. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  2. GRB 000528 - WFC measurements
  3. GRB000529: BeppoSAX WFC position
  4. GRB000519, BVRI field photometry
  5. IPN triangulation of GRB000519
  6. GRB000508B, optical photometry
  7. GRB000508B, BVR field photometry
  8. Possible GRB-related phenomenon
  9. RXTE/ASM and IPN localization of GRB 000508B
  10. GRB000424, UBVRI field photometry
  11. GRB000418, UBVRI field photometry update
  12. GRB000424, optical observations
  13. GRB 000429, optical observation
  14. GRB 000429, UBVRI field photometry
  15. IPN localization of GRB000429
  16. GRB 000418, UBVRI field photometry
  17. GRB 000418, optical observation
  18. GRB 000418, Optical Observation
  19. IPN error box for GRB000418
  20. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  21. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  22. Budget cuts in BeppoSAX operations: impact on GRB observations
  23. GRB 000408, optical observations
  24. GRB 991208, UBVRI field photometry
  25. GRB000301c results
  26. GRB000408, lotis optical observations
  27. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  28. GRB000301C - Addendum to GCN 623
  29. GRB 000326: Optical Observations
  30. GRB000326, Radio observations
  31. GRB000326 [IPN Position]
  32. GRB000313, Radio observations
  33. GRB 000313 - optical transient in the BATSE error box
  34. GRB000301C - R photometry
  35. GRB 000307, Optical Observations
  36. GRB 000307, BVRI Field Photometry
  37. GRB 000301C: Optical Spectrum and Redshift
  38. GRB 000301C: Optical Spectrum and Redshift
  39. GRB 000301C: A Precise Redshift Determination
  40. GRB 000301C, Optical Observation
  41. GRB 000301C: HST/STIS CCD Imaging of the field
  42. GRB000301C, optical R-band observations
  43. GRB 000301C Optical Observations
  44. GRB 000301C: K' Observations
  45. GRB000301C OT candidate optical observations
  46. GRB000301C - Host galaxy not detected in R (?)
  47. Optical observations of GRB000301c
  48. GRB000301C, Radio observations
  49. GRB000301C, Radio observations
  50. GRB 000301c near-IR observations
  51. GRB 000301C, UBVRI field photometry
  52. GRB000301C 250 GHz detection
  53. GRB 000301C R-band observation
  54. GRB000301C, near-infrared observations (JHK' photometry)
  55. GRB 000301C: OT confirmed
  56. GRB000301c optical observations
  57. GRB000301C, optical observations
  58. GRB000301c, near-infrared observations
  59. GRB000301C
  60. GRB 000301C : Optical Candidate
  61. GRB000226 [IPN Position]
  62. HST Observations of GRB 990712
  63. GRB 000214 near-IR observations
  64. GRB 000214, Radio Observations
  65. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  66. GRB000210, Radio Observations
  67. GRB 000115, BVRI field photometry
  68. GRB000214: BeppoSAX GRBM and WFC Detection
  69. BATSE GRB trigger criterion changed
  70. Optical observations of GRB000210
  71. GRB000210 X-ray afterglow
  72. GRB000214: X-ray afterglow candidate
  73. GRB000214 refined BeppoSAX-WFC position
  74. Optical observations of the Chandra X-ray source for GRB000210
  75. GRB000210, Radio Observations
  76. GRB000201, Radio Observations
  77. GRB000210: BeppoSAX GRBM and WFC Detection
  78. GRB000201 Optical Observations
  79. GRB 000131 Optical Observations
  80. GRB000126 Optical Observations
  81. BATSE GRB trigger criteria changed
  82. BATSE+IPN location of GRB000131
  83. IPN localization of GRB000131
  84. GRB 000126, optical observations
  85. GRB991216, UBVRIJHK field photometry
  86. GCN resumes full operations
  87. IPN error boxes for GRB991229
  88. GRB 991216: J band spectrophotometry
  89. GRB 991216: Detection of the Host and/or Absorber Galaxy
  90. GRB 991216 RXTE ASM Observations
  91. GRB 991216: Updated BATSE parameters
  92. GRB 991217 (SAX J2303.2+0015) Optical observations
  93. Chandra observation of the X-ray afterglow of GRB991216
  94. SAX J2303.2+0015 Optical observations
  95. IR observations of GRB991216
  96. GRB 991217 (SAX J2303.2+0015) Optical observations
  97. GRB 991216 Radio Observations
  98. GRB 991208 Keck Spectroscopy
  99. GRB 991208 Infrared Detection
  100. GRB991216

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