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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"

28044 results found.

  1. GRB001007: Optical observations
  2. ASM Localization of GRB 001025
  3. GRB001007, Radio observations
  4. GRB 001018, Possible Radio Afterglow
  5. GRB001018, Gamma Ray Observations
  6. IPN TRIANGULATION OF GRB001019
  7. IPN TRIANGULATION OF GRB001018
  8. IPN TRIANGULATION OF GRB 001017
  9. V,R,I band observations of GRB000926
  10. HETE positions added to GCN
  11. GRB000926 - Amateur Optical Observations
  12. CONCAM null result on GRB001005
  13. IPN triangulation of GRB001005
  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. GRB 000926, Optical Observations
  20. GRB000926 K'-band Observation
  21. J and K band observations of GRB 000926
  22. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  23. CONCAM crude optical limits before and after GRB000926
  24. GRB 000926: Preliminary R-band Lightcurve
  25. Spectroscopic Redshift of GRB 000926
  26. GRB 000926: Optical candidate
  27. Optical candidate for GRB000926
  28. GRB 000911, BVRI field photometry
  29. GRB000911, Radio and Optical observations
  30. GRB000911: Optical observations
  31. GRB000830, BVRI field photometry
  32. GRB000210, Optical observations
  33. "Snapshot" afterglow IDs and GRB 000830
  34. GRB000730, Gamma Ray Observations
  35. GRB000812, Radio observations
  36. GRB000801, Gamma Ray Observations
  37. GRB000801, VLT-Antu R-band observations
  38. GRB 991208 Host Galaxy Imaging
  39. IPN localization of GRB000730B
  40. GRB 990510: Possible detection of a host galaxy
  41. GRB 990510 Host Galaxy Discovery
  42. IPN localization of GRB000727
  43. GRB 990712: Late time HST/STIS Observations
  44. GRB 991216, HST/STIS observations
  45. GRB000620, Radio Observations
  46. GRB000630, optical observations
  47. GRB000630, Revised BVRI Field Photometry
  48. GRB000630, Optical Observations
  49. GRB000630, optical observations
  50. GRB000630, optical observations
  51. GRB000630, BVRI Field Photometry
  52. GRB000630, optical observations
  53. GRB000630: Optical observations
  54. GRB000630, Radio Observations
  55. possible optical counterpart of GRB 000630
  56. GRB 000620, optical observations
  57. GRB000418, HST/STIS Observations
  58. GRB990123: Late-time HST/STIS observations of the host
  59. GRB000620, optical observations
  60. GRB000615: H-band observations
  61. GRB990308, HST/STIS observations of the host galaxy
  62. GRB000620 - Optical observations
  63. GRB000620 Optical observations
  64. GRB000620: BeppoSAX WFC and GRBM detection
  65. GRB000607, optical observations
  66. GRB 000615: NIR further observations
  67. GRB990123, HST/STIS observations of the host galaxy
  68. GRB000616 optical observations
  69. GRB 000615, near-infrared observations
  70. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  71. GRB000615, further R-band photometry
  72. GRB 000615: NIR observations
  73. GRB000615: BeppoSAX NFI follow-up preliminary analysis
  74. GRB000615, R-band photometry
  75. The Hosts of GRB 980703 and GRB 971214
  76. GRB 000301C: Further Late-Time HST/STIS observations
  77. GRB000528: follow-up X-ray measurements and update of IPN annulus
  78. GRB980519, HST/STIS observations of the host galaxy
  79. GRB000604 optical non-detection
  80. GRB000604 - Optical observations
  81. GRB000604, optical observations
  82. GRB000528, optical observations at ESO
  83. GRB 000604 optical observations
  84. GRB 000418: Detection of the Host Galaxy
  85. GRB000604, optical observations, comparison with DPOSS
  86. GRB000528, Radio Observations
  87. X-ray Afterglow of GRB 000529
  88. GRB000529: BeppoSAX NFI follow-up preliminary analysis
  89. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  90. GRB 000528 - WFC measurements
  91. GRB000519, BVRI field photometry
  92. IPN triangulation of GRB000519
  93. GRB000508B, optical photometry
  94. GRB000508B, BVR field photometry
  95. Possible GRB-related phenomenon
  96. RXTE/ASM and IPN localization of GRB 000508B
  97. GRB000424, UBVRI field photometry
  98. GRB000418, UBVRI field photometry update
  99. GRB000424, optical observations
  100. GRB 000429, optical observation

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Download all Circulars as a .tar.gz archive (updated once a day):
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