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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"

43623 results found.

  1. GRB 001025B, I-band observations
  2. XMM-Newton observation of GRB001025
  3. GRB001025B, Radio observations
  4. GRB 001025 Optical Observations
  5. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  6. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  7. IPN triangulation of GRB001025
  8. GRB001007: Optical observations
  9. ASM Localization of GRB 001025
  10. GRB001007, Radio observations
  11. IPN TRIANGULATION OF GRB001020
  12. GRB001019, Optical Observations
  13. GRB 001018, Possible Radio Afterglow
  14. GRB001018, Gamma Ray Observations
  15. IPN TRIANGULATION OF GRB001019
  16. IPN TRIANGULATION OF GRB001018
  17. IPN TRIANGULATION OF GRB 001017
  18. GRB 000926: Improved Absorber Redshift
  19. V,R,I band observations of GRB000926
  20. The Likely Optical/Infrared Afterglow of GRB 001011
  21. HETE positions added to GCN
  22. GRB001011 BeppoSAX/WFC refined position
  23. BeppoSAX ALERT: GRB001011
  24. GRB 001007, BVR-band observations
  25. GRB000926 - Amateur Optical Observations
  26. GRB001007: Optical observations
  27. CONCAM null result on GRB001005
  28. IPN triangulation of GRB001007
  29. GRB 000926 : the host galaxy
  30. HETE-2 Launches Successfully
  31. IPN triangulation of GRB001005
  32. HETE-2 48 hour Launch Delay
  33. GRB 000926 Chandra Observation
  34. IPN triangulation of GRB 001004
  35. Public availability of BeppoSAX data of GRB000926
  36. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  37. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  38. GRB000926 - Optical observations
  39. GRB000926 - Optical observations
  40. GRB 000926, Optical Decay
  41. GRB000911: VLT infrared observation
  42. GRB000926 - Optical observations
  43. GRB000926 - 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. IPN triangulation of GRB000911
  76. IPN triangulation of GRB000910
  77. False GRB alarm from RXTE/ASM on 8 Sept 2000
  78. GRB 000830: Optical observations
  79. GRB000830: Optical observations
  80. GRB000830, TNG B-band observations
  81. GRB000830, BVRI field photometry
  82. GRB000830: Optical observations
  83. GRB000210, Optical observations
  84. "Snapshot" afterglow IDs and GRB 000830
  85. GRB000830: Optical observations
  86. IPN triangulation of GRB000830
  87. HST/STIS observations of the host galaxy of GRB 980329
  88. HST/STIS observations of the chaotic environment of GRB 980613
  89. IPN localization of GRB000820
  90. SGR 1806-20 burst activity
  91. GRB000812, TNG R-band observations
  92. GRB000730, Gamma Ray Observations
  93. GRB000812, Radio observations
  94. IPN localization of GRB000812
  95. IPN localization of GRB000811
  96. GRB000801, Gamma Ray Observations
  97. GRB000801, VLT-Antu R-band observations
  98. GRB000301C, UBVI optical observations
  99. GRB000801, Radio Observations
  100. GRB 991208 Host Galaxy Imaging

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