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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. GRB000620: BeppoSAX WFC and GRBM detection
  2. GRB000615, Radio observations
  3. GRB000607, optical observations
  4. GRB 000615: NIR further observations
  5. GRB000620: refined BeppoSAX/WFC coordinates
  6. BeppoSAX ALERT: GRB000620
  7. GRB000620: BeppoSAX Alert
  8. GRB990123, HST/STIS observations of the host galaxy
  9. GRB000616 optical observations
  10. GRB 000615, near-infrared observations
  11. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  12. GRB000616 [IPN Position]
  13. GRB000615B [IPN Position]
  14. GRB000615, further R-band photometry
  15. GRB 000615: NIR observations
  16. GRB000615: BeppoSAX NFI follow-up preliminary analysis
  17. GRB000615, R-band photometry
  18. GRB000615: BeppoSAX refined coordinates
  19. GRB980425, HST/STIS observations of the host galaxy
  20. GRB000615: BeppoSAX GRB Alert
  21. The Hosts of GRB 980703 and GRB 971214
  22. GRB 000301C: Further Late-Time HST/STIS observations
  23. GRB000528: follow-up X-ray measurements and update of IPN annulus
  24. Optical Follow-up of GRB000529 Error Box
  25. GRB980519, HST/STIS observations of the host galaxy
  26. GRB000607, Radio Observations
  27. BeppoSAX X-ray transient/possible GRB000608
  28. GRB000604 optical non-detection
  29. GRB000604 - Optical observations
  30. GRB000607, A SHORT, HARD BURST
  31. GRB000604, optical observations
  32. GRB000528, optical observations at ESO
  33. GRB 000604 optical observations
  34. GRB 000418: Detection of the Host Galaxy
  35. GRB000604, optical observations, comparison with DPOSS
  36. GRB000604 [IPN Position]
  37. GRB000528, Radio Observations
  38. X-ray Afterglow of GRB 000529
  39. GRB000529: BeppoSAX NFI follow-up preliminary analysis
  40. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  41. GRB000529: Optical Observations
  42. IPN localization and time history of GRB000528
  43. New IPN localization of GRB000529
  44. GRB000519: Optical observations
  45. IPN localization of GRB000529
  46. GRB 000528 - WFC measurements
  47. GRB000529: BeppoSAX WFC position
  48. GRB000528: BeppoSAX GRBM observations
  49. GRB 000528 Optical Observations
  50. GRB000519, BVRI field photometry
  51. IPN triangulation of GRB000519
  52. IPN triangulation of GRB000516
  53. Re: GRB000508B : Optical observations
  54. GRB 000418, Optical observation
  55. GRB000508B, optical photometry
  56. GRB000508B, BVR field photometry
  57. Possible GRB-related phenomenon
  58. RXTE/ASM and IPN localization of GRB 000508B
  59. GRB000424, UBVRI field photometry
  60. GRB 000424 Optical Observations
  61. GRB000418, UBVRI field photometry update
  62. The redshift of GRB 000418
  63. GRB000424, optical observations
  64. GRB 000429, optical observation
  65. GRB 000429, UBVRI field photometry
  66. IPN localization of GRB000429
  67. GRB 000418, UBVRI field photometry
  68. GRB000418, Radio detection
  69. GRB000418, K'-band photometry
  70. GRB 000418, Optical Observation
  71. GRB 000418, optical observation
  72. GRB000424 Optical Observations
  73. GRB 000418, Optical Observation
  74. GRB000424, optical observations
  75. GRB000424, optical observations
  76. GRB 000424, Optical Observations
  77. GRB 000418, Optical Observation
  78. GRB000418, near-infrared observations
  79. BeppoSAX GRB000424
  80. Correction to IPN error box for GRB000419
  81. IPN error box for GRB000418
  82. GRB000419 [IPN Position]
  83. GRB000416 Optical Observations
  84. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  85. GRB000416 BRJK observations
  86. 1SAXJ1715.0-7134 refined position
  87. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  88. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  89. Budget cuts in BeppoSAX operations: impact on GRB observations
  90. GRB 000408, optical observations
  91. Refined IPN error box for GRB000408
  92. GRB 991208, UBVRI field photometry
  93. GRB000301c results
  94. GRB000408: Optical CCD Observations from MIRO
  95. GRB000408, lotis optical observations
  96. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  97. GRB000408 [IPN Position]
  98. GRB000326 Optical Observations
  99. GRB000301C - Addendum to GCN 623
  100. GRB000301C - R magnitude lower limit

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