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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"

43612 results found.

  1. GRB001019, Optical Observations
  2. GRB 001018, Possible Radio Afterglow
  3. GRB001018, Gamma Ray Observations
  4. IPN TRIANGULATION OF GRB001019
  5. IPN TRIANGULATION OF GRB001018
  6. IPN TRIANGULATION OF GRB 001017
  7. GRB 000926: Improved Absorber Redshift
  8. V,R,I band observations of GRB000926
  9. The Likely Optical/Infrared Afterglow of GRB 001011
  10. HETE positions added to GCN
  11. GRB001011 BeppoSAX/WFC refined position
  12. BeppoSAX ALERT: GRB001011
  13. GRB 001007, BVR-band observations
  14. GRB000926 - Amateur Optical Observations
  15. GRB001007: Optical observations
  16. CONCAM null result on GRB001005
  17. IPN triangulation of GRB001007
  18. GRB 000926 : the host galaxy
  19. HETE-2 Launches Successfully
  20. IPN triangulation of GRB001005
  21. HETE-2 48 hour Launch Delay
  22. GRB 000926 Chandra Observation
  23. IPN triangulation of GRB 001004
  24. Public availability of BeppoSAX data of GRB000926
  25. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  26. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  27. GRB000926 - Optical observations
  28. GRB000926 - Optical observations
  29. GRB 000926, Optical Decay
  30. GRB000911: VLT infrared observation
  31. GRB000926 - Optical observations
  32. GRB000926 - Optical observations
  33. GRB 000926: optical observations
  34. GRB000926 - Optical observations
  35. GRB000911: optical VLT observations
  36. GRB000926 K'-band Observation
  37. GRB000926 : increasing optical decay slope
  38. GRB000926 optical observations
  39. GRB000926 - Optical observations
  40. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  41. J and K band observations of GRB 000926
  42. GRB000911 Optical Observations
  43. GRB 000926: Lightcurve Update and Predictions
  44. GRB 000926, optical observation by Oksanen (vsnet-grb)
  45. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  46. GRB000926: Optical observations
  47. CONCAM crude optical limits before and after GRB000926
  48. GRB 000926: Preliminary R-band Lightcurve
  49. GRB 000926 HST/Chandra TOO Status
  50. Spectroscopic Redshift of GRB 000926
  51. GRB 000926, Optical Observation
  52. GRB000926, radio observations
  53. GRB 000926: Optical candidate
  54. Optical candidate for GRB000926
  55. IPN triangulation of GRB000926
  56. IPN triangulation of GRB000926
  57. GRB 000911, BVRI field photometry
  58. GRB000911: Corrected coordinates
  59. GRB000911: Sub-millimeter observations
  60. IPN triangulation of GRB000925
  61. GRB000911: Optical Transient
  62. GRB000911, Radio and Optical observations
  63. GRB000911, Radio observations
  64. IPN triangulation of GRB000911
  65. IPN triangulation of GRB000910
  66. False GRB alarm from RXTE/ASM on 8 Sept 2000
  67. GRB 000830: Optical observations
  68. GRB000830: Optical observations
  69. GRB000830, TNG B-band observations
  70. GRB000830, BVRI field photometry
  71. GRB000830: Optical observations
  72. GRB000210, Optical observations
  73. "Snapshot" afterglow IDs and GRB 000830
  74. GRB000830: Optical observations
  75. IPN triangulation of GRB000830
  76. HST/STIS observations of the host galaxy of GRB 980329
  77. HST/STIS observations of the chaotic environment of GRB 980613
  78. IPN localization of GRB000820
  79. SGR 1806-20 burst activity
  80. GRB000812, TNG R-band observations
  81. GRB000730, Gamma Ray Observations
  82. GRB000812, Radio observations
  83. IPN localization of GRB000812
  84. IPN localization of GRB000811
  85. GRB000801, Gamma Ray Observations
  86. GRB000801, VLT-Antu R-band observations
  87. GRB000301C, UBVI optical observations
  88. GRB000801, Radio Observations
  89. GRB 991208 Host Galaxy Imaging
  90. IPN localization of GRB000801
  91. IPN localization of GRB000730B
  92. IPN localization of GRB000730B
  93. IPN localization of GRB000730
  94. GRB 990510: Possible detection of a host galaxy
  95. GRB 990510 Host Galaxy Discovery
  96. GRB 000727, optical observations
  97. IPN localization of GRB000727
  98. GRB 990705, HST/STIS observations of the host galaxy
  99. GRB 990712: Late time HST/STIS Observations
  100. GRB 991216, HST/STIS observations

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