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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.

Lucene Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. Re: GRB000508B : Optical observations
  2. GRB 000418, Optical observation
  3. GRB000508B, optical photometry
  4. GRB000508B, BVR field photometry
  5. Possible GRB-related phenomenon
  6. RXTE/ASM and IPN localization of GRB 000508B
  7. GRB000424, UBVRI field photometry
  8. GRB 000424 Optical Observations
  9. GRB000418, UBVRI field photometry update
  10. The redshift of GRB 000418
  11. GRB000424, optical observations
  12. GRB 000429, optical observation
  13. GRB 000429, UBVRI field photometry
  14. IPN localization of GRB000429
  15. GRB 000418, UBVRI field photometry
  16. GRB000418, Radio detection
  17. GRB000418, K'-band photometry
  18. GRB 000418, Optical Observation
  19. GRB 000418, optical observation
  20. GRB000424 Optical Observations
  21. GRB 000418, Optical Observation
  22. GRB000424, optical observations
  23. GRB000424, optical observations
  24. GRB 000424, Optical Observations
  25. GRB 000418, Optical Observation
  26. GRB000418, near-infrared observations
  27. BeppoSAX GRB000424
  28. Correction to IPN error box for GRB000419
  29. IPN error box for GRB000418
  30. GRB000419 [IPN Position]
  31. GRB000416 Optical Observations
  32. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  33. GRB000416 BRJK observations
  34. 1SAXJ1715.0-7134 refined position
  35. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  36. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  37. Budget cuts in BeppoSAX operations: impact on GRB observations
  38. GRB 000408, optical observations
  39. Refined IPN error box for GRB000408
  40. GRB 991208, UBVRI field photometry
  41. GRB000301c results
  42. GRB000408: Optical CCD Observations from MIRO
  43. GRB000408, lotis optical observations
  44. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  45. GRB000408 [IPN Position]
  46. GRB000326 Optical Observations
  47. GRB000301C - Addendum to GCN 623
  48. GRB000301C - R magnitude lower limit
  49. GRB000326, Further VLA observations
  50. GRB 000323, optical observations
  51. GRB 000326: Optical Observations
  52. GRB000326, Radio observations
  53. GRB000326 [IPN Position]
  54. GRB 000307 optical observations
  55. GRB000323 [IPN Position]
  56. Single error box for GRB000315
  57. GRB000315 [IPN Positions]
  58. GRB000313, Radio observations
  59. GRB 000313 - optical transient in the BATSE error box
  60. GRB000301C - B and R photometry
  61. GRB000301C - R photometry
  62. GRB 000307, Optical Observations
  63. GRB 000307, BVRI Field Photometry
  64. GRB 000301C: Optical Spectrum and Redshift
  65. GRB 000301C: Optical Spectrum and Redshift
  66. GRB 000301C: A Precise Redshift Determination
  67. GRB 000301C, Optical Observation
  68. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  69. GRB 000301C: HST/STIS CCD Imaging of the field
  70. IPN error box for GRB000307
  71. GRB 000301c: K' observations
  72. GRB000301C, optical R-band observations
  73. GRB000301c - R photometry and nearby faint source confirmation
  74. GRB 000301C, Optical Observation
  75. GRB 000301c: K' observations
  76. GRB 000301C Optical Observations
  77. GRB 000301C: K' Observations
  78. GRB000301C OT candidate optical observations
  79. GRB000301C - Host galaxy not detected in R (?)
  80. Optical observations of GRB000301c
  81. GRB000301C, Radio observations
  82. GRB000301C, Radio observations
  83. GRB000301C optical observations
  84. GRB000301C, near-infrared observations (JHK' imaging)
  85. GRB 000301c near-IR observations
  86. GRB 000301C, Optical Color
  87. GRB000301C, Optical Spectroscopy
  88. GRB 000301C, UBVRI field photometry
  89. GRB 000301C, Optical Observation
  90. GRB000301C, optical observations
  91. GRB000301C 250 GHz detection
  92. GRB 000301C R-band observation
  93. GRB 000301C, Optical Observation
  94. GRB000301C, near-infrared observations (JHK' photometry)
  95. GRB 000301C: OT confirmed
  96. GRB000301c optical observations
  97. GRB 000301A, Radio Observations
  98. GRB000301C, optical observations
  99. GRB000301c, near-infrared observations
  100. GRB000301C

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