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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"

35428 results found.

  1. GRB 000418, UBVRI field photometry
  2. GRB000418, K'-band photometry
  3. GRB 000418, Optical Observation
  4. GRB 000418, optical observation
  5. GRB000424 Optical Observations
  6. GRB 000418, Optical Observation
  7. GRB 000424, Optical Observations
  8. GRB 000418, Optical Observation
  9. GRB000418, near-infrared observations
  10. Correction to IPN error box for GRB000419
  11. IPN error box for GRB000418
  12. GRB000419 [IPN Position]
  13. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  14. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  15. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  16. Budget cuts in BeppoSAX operations: impact on GRB observations
  17. GRB 000408, optical observations
  18. Refined IPN error box for GRB000408
  19. GRB 991208, UBVRI field photometry
  20. GRB000301c results
  21. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  22. GRB000408 [IPN Position]
  23. GRB000326 Optical Observations
  24. GRB000301C - Addendum to GCN 623
  25. GRB000301C - R magnitude lower limit
  26. GRB 000323, optical observations
  27. GRB 000326: Optical Observations
  28. GRB000326, Radio observations
  29. GRB000326 [IPN Position]
  30. GRB 000307 optical observations
  31. GRB000323 [IPN Position]
  32. GRB000315 [IPN Positions]
  33. GRB 000313 - optical transient in the BATSE error box
  34. GRB000301C - B and R photometry
  35. GRB000301C - R photometry
  36. GRB 000307, Optical Observations
  37. GRB 000307, BVRI Field Photometry
  38. GRB 000301C: Optical Spectrum and Redshift
  39. GRB 000301C: Optical Spectrum and Redshift
  40. GRB 000301C: A Precise Redshift Determination
  41. GRB 000301C, Optical Observation
  42. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  43. GRB 000301C: HST/STIS CCD Imaging of the field
  44. IPN error box for GRB000307
  45. GRB 000301c: K' observations
  46. GRB000301C, optical R-band observations
  47. GRB000301c - R photometry and nearby faint source confirmation
  48. GRB 000301C, Optical Observation
  49. GRB 000301c: K' observations
  50. GRB 000301C Optical Observations
  51. GRB 000301C: K' Observations
  52. GRB000301C - Host galaxy not detected in R (?)
  53. Optical observations of GRB000301c
  54. GRB000301C optical observations
  55. GRB 000301c near-IR observations
  56. GRB 000301C, Optical Color
  57. GRB000301C, Optical Spectroscopy
  58. GRB 000301C, UBVRI field photometry
  59. GRB 000301C, Optical Observation
  60. GRB000301C 250 GHz detection
  61. GRB 000301C R-band observation
  62. GRB 000301C, Optical Observation
  63. GRB000301C, near-infrared observations (JHK' photometry)
  64. GRB 000301C: OT confirmed
  65. GRB000301c optical observations
  66. GRB 000301A, Radio Observations
  67. GRB000301C, optical observations
  68. GRB000301c, near-infrared observations
  69. GRB000301C
  70. GRB 000301C : Optical Candidate
  71. GRB000301C: RXTE/ASM and IPN localizations
  72. GRB000226 [IPN Position]
  73. HST Observations of GRB 990712
  74. GRB 000214 near-IR observations
  75. GRB 000115 Optical observations
  76. GRB 000214, Radio Observations
  77. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  78. GRB 000115, BVRI field photometry
  79. IPN annulus for GRB000214
  80. BATSE GRB trigger criterion changed
  81. GRB000210 X-ray afterglow
  82. GRB000214: X-ray afterglow candidate
  83. BeppoSAX GRB000214 ("S. Valentine's day GRB")
  84. GRB 000210: BATSE Observations
  85. Optical observations of the Chandra X-ray source for GRB000210
  86. Chandra Observations of GRB000210 X-ray Afterglow
  87. IPN triangulation of GRB000210
  88. GRB 000201: TAROT optical observations
  89. GRB 000131 Optical Observations
  90. GRB000126 Optical Observations
  91. BATSE GRB trigger criteria changed
  92. GRB 991208, radio observations
  93. BATSE+IPN location of GRB000131
  94. IPN localization of GRB000131
  95. GRB 000126, optical observations
  96. GRB000126, optical observations
  97. BATSE location of GRB000126
  98. IPN localization of GRB000126
  99. GRB 000115 Optical observations
  100. BATSE Observations of GRB000115

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