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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. GRB 001025 Optical Observations
  2. GRB 001025A, optical observation
  3. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  4. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  5. IPN triangulation of GRB001025
  6. GRB001007: Optical observations
  7. ASM Localization of GRB 001025
  8. GRB001007, Radio observations
  9. IPN TRIANGULATION OF GRB001020
  10. GRB001019, Optical Observations
  11. GRB 001018, Possible Radio Afterglow
  12. GRB001018, Gamma Ray Observations
  13. IPN TRIANGULATION OF GRB001019
  14. CORRECTION TO PEAK FLUX OF GRB001018
  15. IPN TRIANGULATION OF GRB001018
  16. IPN TRIANGULATION OF GRB 001017
  17. GRB 000926: Improved Absorber Redshift
  18. V,R,I band observations of GRB000926
  19. The Likely Optical/Infrared Afterglow of GRB 001011
  20. HETE positions added to GCN
  21. GRB001011 BeppoSAX/WFC refined position
  22. BeppoSAX ALERT: GRB001011
  23. GRB 001007, BVR-band observations
  24. GRB000926 - Amateur Optical Observations
  25. GRB001007: Optical observations
  26. CONCAM null result on GRB001005
  27. IPN triangulation of GRB001007
  28. GRB 000926 : the host galaxy
  29. HETE-2 Launches Successfully
  30. IPN triangulation of GRB001005
  31. HETE-2 48 hour Launch Delay
  32. GRB 000926 Chandra Observation
  33. IPN triangulation of GRB 001004
  34. Public availability of BeppoSAX data of GRB000926
  35. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  36. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  37. GRB000926 - Optical observations
  38. GRB000926 - Optical observations
  39. GRB 000926, Optical Decay
  40. GRB000911: VLT infrared observation
  41. GRB000926 - Optical observations
  42. GRB000926 - Optical observations
  43. GRB 000926: optical observations
  44. GRB 000926, Optical Observations
  45. GRB000926 - Optical observations
  46. GRB000911: optical VLT observations
  47. GRB000926 K'-band Observation
  48. GRB000926 : increasing optical decay slope
  49. GRB000926 optical observations
  50. GRB000926 - Optical observations
  51. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  52. J and K band observations of GRB 000926
  53. GRB000911 Optical Observations
  54. GRB 000926: Lightcurve Update and Predictions
  55. GRB 000926, optical observation by Oksanen (vsnet-grb)
  56. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  57. GRB000926: Optical observations
  58. CONCAM crude optical limits before and after GRB000926
  59. GRB 000926: Preliminary R-band Lightcurve
  60. GRB 000926 HST/Chandra TOO Status
  61. Spectroscopic Redshift of GRB 000926
  62. GRB 000926, Optical Observation
  63. GRB000926, radio observations
  64. GRB 000926: Optical candidate
  65. Optical candidate for GRB000926
  66. IPN triangulation of GRB000926
  67. IPN triangulation of GRB000926
  68. GRB 000911, BVRI field photometry
  69. GRB000911: Corrected coordinates
  70. GRB000911: Sub-millimeter observations
  71. IPN triangulation of GRB000925
  72. GRB000911: Optical Transient
  73. GRB000911, Radio and Optical observations
  74. GRB000911, Radio observations
  75. GRB000911: Optical observations
  76. IPN triangulation of GRB000911
  77. IPN triangulation of GRB000910
  78. False GRB alarm from RXTE/ASM on 8 Sept 2000
  79. GRB 000830: Optical observations
  80. GRB000830: Optical observations
  81. GRB000830, TNG B-band observations
  82. GRB000830, BVRI field photometry
  83. GRB000830: Optical observations
  84. GRB000210, Optical observations
  85. Chandra Position of GRB000210
  86. "Snapshot" afterglow IDs and GRB 000830
  87. GRB000830: Optical observations
  88. IPN triangulation of GRB000830
  89. HST/STIS observations of the host galaxy of GRB 980329
  90. HST/STIS observations of the chaotic environment of GRB 980613
  91. IPN localization of GRB000820
  92. SGR 1806-20 burst activity
  93. GRB000812, TNG R-band observations
  94. GRB000801 & GRB000730, Gamma Ray Observations
  95. GRB000730, Gamma Ray Observations
  96. GRB000812, Radio observations
  97. IPN localization of GRB000812
  98. IPN localization of GRB000811
  99. GRB000801, Gamma Ray Observations
  100. GRB000801, VLT-Antu R-band observations

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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