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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"

32498 results found.

  1. GRB000607, Radio Observations
  2. GRB000604 optical non-detection
  3. GRB000604 - Optical observations
  4. GRB000604, optical observations
  5. GRB000528, optical observations at ESO
  6. GRB 000604 optical observations
  7. GRB 000418: Detection of the Host Galaxy
  8. GRB000604, optical observations, comparison with DPOSS
  9. GRB000528, Radio Observations
  10. X-ray Afterglow of GRB 000529
  11. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  12. IPN localization and time history of GRB000528
  13. New IPN localization of GRB000529
  14. GRB000519: Optical observations
  15. IPN localization of GRB000529
  16. GRB 000528 - WFC measurements
  17. IPN triangulation of GRB000519
  18. Re: GRB000508B : Optical observations
  19. GRB 000418, Optical observation
  20. GRB000508B, optical photometry
  21. Possible GRB-related phenomenon
  22. GRB 000424 Optical Observations
  23. The redshift of GRB 000418
  24. GRB000424, optical observations
  25. GRB 000429, optical observation
  26. GRB000418, Radio detection
  27. GRB000418, K'-band photometry
  28. GRB 000418, Optical Observation
  29. GRB 000418, optical observation
  30. GRB000424 Optical Observations
  31. GRB 000418, Optical Observation
  32. GRB000424, optical observations
  33. GRB000424, optical observations
  34. GRB 000424, Optical Observations
  35. GRB 000418, Optical Observation
  36. GRB000418, near-infrared observations
  37. BeppoSAX GRB000424
  38. Correction to IPN error box for GRB000419
  39. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  40. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  41. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  42. GRB 000408, optical observations
  43. Refined IPN error box for GRB000408
  44. GRB000301c results
  45. GRB000408: Optical CCD Observations from MIRO
  46. GRB000408, lotis optical observations
  47. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  48. GRB000326 Optical Observations
  49. GRB000301C - Addendum to GCN 623
  50. GRB000326, Further VLA observations
  51. GRB 000323, optical observations
  52. GRB 000326: Optical Observations
  53. GRB000326, Radio observations
  54. GRB 000307 optical observations
  55. Single error box for GRB000315
  56. GRB000313, Radio observations
  57. GRB000301C - B and R photometry
  58. GRB 000307, Optical Observations
  59. GRB 000301C: Optical Spectrum and Redshift
  60. GRB 000301C: Optical Spectrum and Redshift
  61. GRB 000301C: A Precise Redshift Determination
  62. GRB 000301C, Optical Observation
  63. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  64. GRB 000301C: HST/STIS CCD Imaging of the field
  65. GRB000301C, optical R-band observations
  66. GRB000301c - R photometry and nearby faint source confirmation
  67. GRB 000301C, Optical Observation
  68. GRB 000301C Optical Observations
  69. GRB 000301C: K' Observations
  70. GRB000301C OT candidate optical observations
  71. Optical observations of GRB000301c
  72. GRB000301C, Radio observations
  73. GRB000301C, Radio observations
  74. GRB000301C, near-infrared observations (JHK' imaging)
  75. GRB 000301C, Optical Color
  76. GRB 000301C, UBVRI field photometry
  77. GRB 000301C, Optical Observation
  78. GRB000301C, optical observations
  79. GRB000301C 250 GHz detection
  80. GRB 000301C R-band observation
  81. GRB 000301C, Optical Observation
  82. GRB000301C, near-infrared observations (JHK' photometry)
  83. GRB 000301C: OT confirmed
  84. GRB000301c optical observations
  85. GRB 000301A, Radio Observations
  86. GRB000301C, optical observations
  87. GRB000301c, near-infrared observations
  88. GRB000301C
  89. GRB 000301C : Optical Candidate
  90. Radio observations of the error box of GRB000301A
  91. HST Observations of GRB 990712
  92. GRB 000115 Optical observations
  93. GRB 000214, Radio Observations
  94. GRB 000214 ``Valentine's Day Burst'': BeppoSAX NFI Observation
  95. GRB000210, Radio Observations
  96. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  97. IPN annulus for GRB000214
  98. Optical observations of GRB000210
  99. GRB000210 X-ray afterglow
  100. GRB 000210: BATSE Observations

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