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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"

32512 results found.

  1. CORRECTION TO PEAK FLUX OF GRB001018
  2. GRB 000926: Improved Absorber Redshift
  3. V,R,I band observations of GRB000926
  4. The Likely Optical/Infrared Afterglow of GRB 001011
  5. HETE positions added to GCN
  6. GRB 001007, BVR-band observations
  7. GRB001007: Optical observations
  8. CONCAM null result on GRB001005
  9. GRB 000926 : the host galaxy
  10. GRB 000926 Chandra Observation
  11. Public availability of BeppoSAX data of GRB000926
  12. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  13. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  14. GRB000926 - Optical observations
  15. GRB000926 - Optical observations
  16. GRB 000926, Optical Decay
  17. GRB000911: VLT infrared observation
  18. GRB000926 - Optical observations
  19. GRB000926 - Optical observations
  20. GRB 000926: optical observations
  21. GRB 000926, Optical Observations
  22. GRB000926 - Optical observations
  23. GRB000911: optical VLT observations
  24. GRB000926 : increasing optical decay slope
  25. GRB000926 optical observations
  26. GRB000926 - Optical observations
  27. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  28. J and K band observations of GRB 000926
  29. GRB000911 Optical Observations
  30. GRB 000926: Lightcurve Update and Predictions
  31. GRB 000926, optical observation by Oksanen (vsnet-grb)
  32. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  33. GRB000926: Optical observations
  34. GRB 000926: Preliminary R-band Lightcurve
  35. GRB 000926 HST/Chandra TOO Status
  36. Spectroscopic Redshift of GRB 000926
  37. GRB 000926, Optical Observation
  38. GRB000926, radio observations
  39. GRB 000926: Optical candidate
  40. Optical candidate for GRB000926
  41. IPN triangulation of GRB000926
  42. GRB 000911, BVRI field photometry
  43. GRB000911: Corrected coordinates
  44. GRB000911: Sub-millimeter observations
  45. GRB000911: Optical Transient
  46. GRB000911, Radio and Optical observations
  47. GRB000911, Radio observations
  48. GRB000911: Optical observations
  49. False GRB alarm from RXTE/ASM on 8 Sept 2000
  50. GRB 000830: Optical observations
  51. GRB000830: Optical observations
  52. GRB000830, TNG B-band observations
  53. GRB000830: Optical observations
  54. GRB000210, Optical observations
  55. Chandra Position of GRB000210
  56. GRB000830: Optical observations
  57. HST/STIS observations of the host galaxy of GRB 980329
  58. HST/STIS observations of the chaotic environment of GRB 980613
  59. GRB000812, TNG R-band observations
  60. GRB000801 & GRB000730, Gamma Ray Observations
  61. GRB000812, Radio observations
  62. GRB000801, VLT-Antu R-band observations
  63. GRB000301C, UBVI optical observations
  64. GRB000801, Radio Observations
  65. GRB 991208 Host Galaxy Imaging
  66. Updated IPN coordinates for GRB000801
  67. IPN localization of GRB000801
  68. IPN localization of GRB000730B
  69. GRB 990510: Possible detection of a host galaxy
  70. GRB 990510 Host Galaxy Discovery
  71. GRB 000727, optical observations
  72. GRB 990705, HST/STIS observations of the host galaxy
  73. GRB 990712: Late time HST/STIS Observations
  74. GRB 991216, HST/STIS observations
  75. GRB000620, Radio Observations
  76. GRB981226, HST/STIS observations of the host galaxy
  77. GRB000630, optical observations
  78. GRB 000630: Detection of the Optical Afterglow
  79. GRB000630, Revised BVRI Field Photometry
  80. GRB000630, Optical Observations
  81. GRB000630, optical observations
  82. GRB000630, optical observations
  83. GRB000630, optical observations
  84. GRB000630, optical observations
  85. GRB000630: Optical observations
  86. GRB000630, Radio Observations
  87. possible optical counterpart of GRB 000630
  88. GRB 000623, optical observations
  89. GRB 000620, optical observations
  90. GRB000418, HST/STIS Observations
  91. GRB990123: Late-time HST/STIS observations of the host
  92. GRB 990506, HST/STIS Observations of the Host Galaxy
  93. GRB 000620: J-band observations
  94. GRB000620, optical observations
  95. GRB000615: H-band observations
  96. GRB990308, HST/STIS observations of the host galaxy
  97. GRB000620 - Optical observations
  98. GRB000620 Optical observations
  99. IPN annulus for GRB000620
  100. GRB000615, Radio observations

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