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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"

32513 results found.

  1. GRB 001018, Possible Radio Afterglow
  2. CORRECTION TO PEAK FLUX OF GRB001018
  3. GRB 000926: Improved Absorber Redshift
  4. V,R,I band observations of GRB000926
  5. The Likely Optical/Infrared Afterglow of GRB 001011
  6. HETE positions added to GCN
  7. GRB 001007, BVR-band observations
  8. GRB001007: Optical observations
  9. CONCAM null result on GRB001005
  10. GRB 000926 : the host galaxy
  11. GRB 000926 Chandra Observation
  12. Public availability of BeppoSAX data of GRB000926
  13. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  14. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  15. GRB000926 - Optical observations
  16. GRB000926 - Optical observations
  17. GRB 000926, Optical Decay
  18. GRB000911: VLT infrared observation
  19. GRB000926 - Optical observations
  20. GRB000926 - Optical observations
  21. GRB 000926: optical observations
  22. GRB 000926, Optical Observations
  23. GRB000926 - Optical observations
  24. GRB000911: optical VLT observations
  25. GRB000926 : increasing optical decay slope
  26. GRB000926 optical observations
  27. GRB000926 - Optical observations
  28. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  29. J and K band observations of GRB 000926
  30. GRB000911 Optical Observations
  31. GRB 000926: Lightcurve Update and Predictions
  32. GRB 000926, optical observation by Oksanen (vsnet-grb)
  33. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  34. GRB000926: Optical observations
  35. GRB 000926: Preliminary R-band Lightcurve
  36. GRB 000926 HST/Chandra TOO Status
  37. Spectroscopic Redshift of GRB 000926
  38. GRB 000926, Optical Observation
  39. GRB000926, radio observations
  40. GRB 000926: Optical candidate
  41. Optical candidate for GRB000926
  42. IPN triangulation of GRB000926
  43. GRB 000911, BVRI field photometry
  44. GRB000911: Corrected coordinates
  45. GRB000911: Sub-millimeter observations
  46. GRB000911: Optical Transient
  47. GRB000911, Radio and Optical observations
  48. GRB000911, Radio observations
  49. GRB000911: Optical observations
  50. False GRB alarm from RXTE/ASM on 8 Sept 2000
  51. GRB 000830: Optical observations
  52. GRB000830: Optical observations
  53. GRB000830, TNG B-band observations
  54. GRB000830: Optical observations
  55. GRB000210, Optical observations
  56. Chandra Position of GRB000210
  57. GRB000830: Optical observations
  58. HST/STIS observations of the host galaxy of GRB 980329
  59. HST/STIS observations of the chaotic environment of GRB 980613
  60. GRB000812, TNG R-band observations
  61. GRB000801 & GRB000730, Gamma Ray Observations
  62. GRB000812, Radio observations
  63. GRB000801, VLT-Antu R-band observations
  64. GRB000301C, UBVI optical observations
  65. GRB000801, Radio Observations
  66. GRB 991208 Host Galaxy Imaging
  67. Updated IPN coordinates for GRB000801
  68. IPN localization of GRB000801
  69. IPN localization of GRB000730B
  70. GRB 990510: Possible detection of a host galaxy
  71. GRB 990510 Host Galaxy Discovery
  72. GRB 000727, optical observations
  73. GRB 990705, HST/STIS observations of the host galaxy
  74. GRB 990712: Late time HST/STIS Observations
  75. GRB 991216, HST/STIS observations
  76. GRB000620, Radio Observations
  77. GRB981226, HST/STIS observations of the host galaxy
  78. GRB000630, optical observations
  79. GRB 000630: Detection of the Optical Afterglow
  80. GRB000630, Revised BVRI Field Photometry
  81. GRB000630, Optical Observations
  82. GRB000630, optical observations
  83. GRB000630, optical observations
  84. GRB000630, optical observations
  85. GRB000630, optical observations
  86. GRB000630: Optical observations
  87. GRB000630, Radio Observations
  88. possible optical counterpart of GRB 000630
  89. GRB 000623, optical observations
  90. GRB 000620, optical observations
  91. GRB000418, HST/STIS Observations
  92. GRB990123: Late-time HST/STIS observations of the host
  93. GRB 990506, HST/STIS Observations of the Host Galaxy
  94. GRB 000620: J-band observations
  95. GRB000620, optical observations
  96. GRB000615: H-band observations
  97. GRB990308, HST/STIS observations of the host galaxy
  98. GRB000620 - Optical observations
  99. GRB000620 Optical observations
  100. IPN annulus for GRB000620

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