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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"
  1. GRB000528: follow-up X-ray measurements and update of IPN annulus
  2. Optical Follow-up of GRB000529 Error Box
  3. GRB980519, HST/STIS observations of the host galaxy
  4. GRB000607, Radio Observations
  5. BeppoSAX X-ray transient/possible GRB000608
  6. GRB000604 optical non-detection
  7. GRB000604 - Optical observations
  8. GRB000607, A SHORT, HARD BURST
  9. GRB000604, optical observations
  10. GRB000528, optical observations at ESO
  11. GRB 000604 optical observations
  12. GRB 000418: Detection of the Host Galaxy
  13. GRB000604, optical observations, comparison with DPOSS
  14. GRB000604 [IPN Position]
  15. GRB000528, Radio Observations
  16. X-ray Afterglow of GRB 000529
  17. GRB000529: BeppoSAX NFI follow-up preliminary analysis
  18. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  19. GRB000529: Optical Observations
  20. IPN localization and time history of GRB000528
  21. New IPN localization of GRB000529
  22. GRB000519: Optical observations
  23. IPN localization of GRB000529
  24. GRB 000528 - WFC measurements
  25. GRB000529: BeppoSAX WFC position
  26. GRB000528: BeppoSAX GRBM observations
  27. GRB 000528 Optical Observations
  28. GRB000519, BVRI field photometry
  29. IPN triangulation of GRB000519
  30. IPN triangulation of GRB000516
  31. Re: GRB000508B : Optical observations
  32. GRB 000418, Optical observation
  33. GRB000508B, optical photometry
  34. GRB000508B, BVR field photometry
  35. Possible GRB-related phenomenon
  36. RXTE/ASM and IPN localization of GRB 000508B
  37. GRB000424, UBVRI field photometry
  38. GRB 000424 Optical Observations
  39. GRB000418, UBVRI field photometry update
  40. The redshift of GRB 000418
  41. GRB000424, optical observations
  42. GRB 000429, optical observation
  43. GRB 000429, UBVRI field photometry
  44. IPN localization of GRB000429
  45. GRB 000418, UBVRI field photometry
  46. GRB000418, Radio detection
  47. GRB000418, K'-band photometry
  48. GRB 000418, Optical Observation
  49. GRB 000418, optical observation
  50. GRB000424 Optical Observations
  51. GRB 000418, Optical Observation
  52. GRB000424, optical observations
  53. GRB000424, optical observations
  54. GRB 000424, Optical Observations
  55. GRB 000418, Optical Observation
  56. GRB000418, near-infrared observations
  57. BeppoSAX GRB000424
  58. Correction to IPN error box for GRB000419
  59. IPN error box for GRB000418
  60. GRB000419 [IPN Position]
  61. GRB000416 Optical Observations
  62. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  63. GRB000416 BRJK observations
  64. 1SAXJ1715.0-7134 refined position
  65. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  66. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  67. Budget cuts in BeppoSAX operations: impact on GRB observations
  68. GRB 000408, optical observations
  69. Refined IPN error box for GRB000408
  70. GRB 991208, UBVRI field photometry
  71. GRB000301c results
  72. GRB000408: Optical CCD Observations from MIRO
  73. GRB000408, lotis optical observations
  74. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  75. GRB000408 [IPN Position]
  76. GRB000326 Optical Observations
  77. GRB000301C - Addendum to GCN 623
  78. GRB000301C - R magnitude lower limit
  79. GRB000326, Further VLA observations
  80. GRB 000323, optical observations
  81. GRB 000326: Optical Observations
  82. GRB000326, Radio observations
  83. GRB000326 [IPN Position]
  84. GRB 000307 optical observations
  85. GRB000323 [IPN Position]
  86. Single error box for GRB000315
  87. GRB000315 [IPN Positions]
  88. GRB000313, Radio observations
  89. GRB 000313 - optical transient in the BATSE error box
  90. GRB000301C - B and R photometry
  91. GRB000301C - R photometry
  92. GRB 000307, Optical Observations
  93. GRB 000307, BVRI Field Photometry
  94. GRB 000301C: Optical Spectrum and Redshift
  95. GRB 000301C: Optical Spectrum and Redshift
  96. GRB 000301C: A Precise Redshift Determination
  97. GRB 000301C, Optical Observation
  98. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  99. GRB 000301C: HST/STIS CCD Imaging of the field
  100. IPN error box for GRB000307

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