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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. GRB001011 BeppoSAX/WFC refined position
  2. BeppoSAX ALERT: GRB001011
  3. GRB 001007, BVR-band observations
  4. GRB000926 - Amateur Optical Observations
  5. GRB001007: Optical observations
  6. CONCAM null result on GRB001005
  7. IPN triangulation of GRB001007
  8. GRB 000926 : the host galaxy
  9. HETE-2 Launches Successfully
  10. IPN triangulation of GRB001005
  11. HETE-2 48 hour Launch Delay
  12. GRB 000926 Chandra Observation
  13. IPN triangulation of GRB 001004
  14. Public availability of BeppoSAX data of GRB000926
  15. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  16. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  17. GRB000926 - Optical observations
  18. GRB000926 - Optical observations
  19. GRB 000926, Optical Decay
  20. GRB000911: VLT infrared observation
  21. GRB000926 - Optical observations
  22. GRB000926 - Optical observations
  23. GRB 000926: optical observations
  24. GRB 000926, Optical Observations
  25. GRB000926 - Optical observations
  26. GRB000911: optical VLT observations
  27. GRB000926 K'-band Observation
  28. GRB000926 : increasing optical decay slope
  29. GRB000926 optical observations
  30. GRB000926 - Optical observations
  31. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  32. J and K band observations of GRB 000926
  33. GRB000911 Optical Observations
  34. GRB 000926: Lightcurve Update and Predictions
  35. GRB 000926, optical observation by Oksanen (vsnet-grb)
  36. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  37. GRB000926: Optical observations
  38. CONCAM crude optical limits before and after GRB000926
  39. GRB 000926: Preliminary R-band Lightcurve
  40. GRB 000926 HST/Chandra TOO Status
  41. Spectroscopic Redshift of GRB 000926
  42. GRB 000926, Optical Observation
  43. GRB000926, radio observations
  44. GRB 000926: Optical candidate
  45. Optical candidate for GRB000926
  46. IPN triangulation of GRB000926
  47. IPN triangulation of GRB000926
  48. GRB 000911, BVRI field photometry
  49. GRB000911: Corrected coordinates
  50. GRB000911: Sub-millimeter observations
  51. IPN triangulation of GRB000925
  52. GRB000911: Optical Transient
  53. GRB000911, Radio and Optical observations
  54. GRB000911, Radio observations
  55. GRB000911: Optical observations
  56. IPN triangulation of GRB000911
  57. IPN triangulation of GRB000910
  58. False GRB alarm from RXTE/ASM on 8 Sept 2000
  59. GRB 000830: Optical observations
  60. GRB000830: Optical observations
  61. GRB000830, TNG B-band observations
  62. GRB000830, BVRI field photometry
  63. GRB000830: Optical observations
  64. GRB000210, Optical observations
  65. Chandra Position of GRB000210
  66. "Snapshot" afterglow IDs and GRB 000830
  67. GRB000830: Optical observations
  68. IPN triangulation of GRB000830
  69. HST/STIS observations of the host galaxy of GRB 980329
  70. HST/STIS observations of the chaotic environment of GRB 980613
  71. IPN localization of GRB000820
  72. SGR 1806-20 burst activity
  73. GRB000812, TNG R-band observations
  74. GRB000801 & GRB000730, Gamma Ray Observations
  75. GRB000730, Gamma Ray Observations
  76. GRB000812, Radio observations
  77. IPN localization of GRB000812
  78. IPN localization of GRB000811
  79. GRB000801, Gamma Ray Observations
  80. GRB000801, VLT-Antu R-band observations
  81. GRB000301C, UBVI optical observations
  82. GRB000801, Radio Observations
  83. GRB 991208 Host Galaxy Imaging
  84. Updated IPN coordinates for GRB000801
  85. IPN localization of GRB000801
  86. IPN localization of GRB000801
  87. IPN localization of GRB000730B
  88. IPN localization of GRB000730B
  89. IPN localization of GRB000730
  90. GRB 990510: Possible detection of a host galaxy
  91. GRB 990510 Host Galaxy Discovery
  92. GRB 000727, optical observations
  93. IPN localization of GRB000727
  94. GRB 990705, HST/STIS observations of the host galaxy
  95. GRB 990712: Late time HST/STIS Observations
  96. GRB 991216, HST/STIS observations
  97. GRB000620, Radio Observations
  98. GRB981226, HST/STIS observations of the host galaxy
  99. GRB000630, optical observations
  100. GRB 000630: Detection of the Optical Afterglow

Advanced

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