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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"

42185 results found.

  1. GRB 001109 X-ray afterglow with BeppoSAX
  2. GRB001109: Optical observations
  3. GRB001109: BeppoSAX/NFI Observations
  4. GRB001109, R-band optical observations
  5. GRB001109, Radio observations
  6. GRB001105, BVRI field photometry
  7. GRB 001105, R-band observation
  8. GRB 001025B, Optical obervations
  9. GRB 991208: HST Imaging of the Host Galaxy
  10. GRB000926: R-image of the host galaxy
  11. GRB 001025B, I-band observations
  12. XMM-Newton observation of GRB001025
  13. GRB001025B, Radio observations
  14. GRB 001025 Optical Observations
  15. GRB 001025A, optical observation
  16. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  17. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  18. IPN triangulation of GRB001025
  19. GRB001007: Optical observations
  20. ASM Localization of GRB 001025
  21. GRB001007, Radio observations
  22. GRB001019, Optical Observations
  23. GRB 001018, Possible Radio Afterglow
  24. GRB001018, Gamma Ray Observations
  25. GRB 000926: Improved Absorber Redshift
  26. V,R,I band observations of GRB000926
  27. The Likely Optical/Infrared Afterglow of GRB 001011
  28. HETE positions added to GCN
  29. GRB 001007, BVR-band observations
  30. GRB000926 - Amateur Optical Observations
  31. GRB001007: Optical observations
  32. CONCAM null result on GRB001005
  33. GRB 000926 : the host galaxy
  34. HETE-2 Launches Successfully
  35. GRB 000926 Chandra Observation
  36. IPN triangulation of GRB 001004
  37. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  38. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  39. GRB000926 - Optical observations
  40. GRB000926 - Optical observations
  41. GRB 000926, Optical Decay
  42. GRB000911: VLT infrared observation
  43. GRB000926 - Optical observations
  44. GRB000926 - Optical observations
  45. GRB 000926: optical observations
  46. GRB 000926, Optical Observations
  47. GRB000926 - Optical observations
  48. GRB000911: optical VLT observations
  49. GRB000926 K'-band Observation
  50. GRB000926 : increasing optical decay slope
  51. GRB000926 optical observations
  52. GRB000926 - Optical observations
  53. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  54. J and K band observations of GRB 000926
  55. GRB000911 Optical Observations
  56. GRB 000926: Lightcurve Update and Predictions
  57. GRB 000926, optical observation by Oksanen (vsnet-grb)
  58. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  59. GRB000926: Optical observations
  60. CONCAM crude optical limits before and after GRB000926
  61. GRB 000926: Preliminary R-band Lightcurve
  62. GRB 000926 HST/Chandra TOO Status
  63. Spectroscopic Redshift of GRB 000926
  64. GRB 000926, Optical Observation
  65. GRB000926, radio observations
  66. GRB 000926: Optical candidate
  67. Optical candidate for GRB000926
  68. IPN triangulation of GRB000926
  69. GRB 000911, BVRI field photometry
  70. GRB000911: Corrected coordinates
  71. GRB000911: Sub-millimeter observations
  72. GRB000911: Optical Transient
  73. GRB000911, Radio and Optical observations
  74. GRB000911, Radio observations
  75. GRB000911: Optical observations
  76. False GRB alarm from RXTE/ASM on 8 Sept 2000
  77. GRB 000830: Optical observations
  78. GRB000830: Optical observations
  79. GRB000830, TNG B-band observations
  80. GRB000830, BVRI field photometry
  81. GRB000830: Optical observations
  82. GRB000210, Optical observations
  83. Chandra Position of GRB000210
  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. SGR 1806-20 burst activity
  90. GRB000812, TNG R-band observations
  91. GRB000801 & GRB000730, Gamma Ray Observations
  92. GRB000812, Radio observations
  93. GRB000801, VLT-Antu R-band observations
  94. GRB000301C, UBVI optical observations
  95. GRB 991208 Host Galaxy Imaging
  96. IPN localization of GRB000730B
  97. GRB 990510: Possible detection of a host galaxy
  98. GRB 990510 Host Galaxy Discovery
  99. GRB 000727, optical observations
  100. GRB 990705, HST/STIS observations of the host galaxy

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