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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"

18330 results found.

  1. GRB 001109 X-ray afterglow with BeppoSAX
  2. CORRECTION to XMM-Newton observation of GRB001025
  3. GRB001109: Optical observations
  4. GRB001109, Radio observations
  5. GRB001105 BVRI field photometry correction
  6. GRB001105, BVRI field photometry
  7. GRB 001025B, Optical obervations
  8. GRB 991208: HST Imaging of the Host Galaxy
  9. GRB 001025B, I-band observations
  10. GRB001007: Optical observations
  11. GRB001007, Radio observations
  12. IPN TRIANGULATION OF GRB 001017
  13. V,R,I band observations of GRB000926
  14. GRB000926 - Amateur Optical Observations
  15. CONCAM null result on GRB001005
  16. HETE-2 Launches Successfully
  17. HETE-2 48 hour Launch Delay
  18. GRB000926 - Optical observations
  19. GRB000926 - Optical observations
  20. GRB 000926, Optical Observations
  21. GRB000926 K'-band Observation
  22. J and K band observations of GRB 000926
  23. GRB 000926, optical observation by Oksanen (vsnet-grb)
  24. CONCAM crude optical limits before and after GRB000926
  25. GRB 000926 HST/Chandra TOO Status
  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. IPN triangulation of GRB000911
  32. GRB000830, BVRI field photometry
  33. IPN triangulation of GRB000830
  34. IPN localization of GRB000812
  35. GRB000801, VLT-Antu R-band observations
  36. GRB 991208 Host Galaxy Imaging
  37. Updated IPN coordinates for GRB000801
  38. IPN localization of GRB000801
  39. GRB 990510: Possible detection of a host galaxy
  40. GRB 990510 Host Galaxy Discovery
  41. GRB 990712: Late time HST/STIS Observations
  42. GRB 991216, HST/STIS observations
  43. GRB000630, optical observations
  44. GRB000630, Revised BVRI Field Photometry
  45. GRB000630, Optical Observations
  46. GRB000630, optical observations
  47. GRB000630, optical observations
  48. GRB000630, BVRI Field Photometry
  49. GRB000630, optical observations
  50. GRB000630: Optical observations
  51. possible optical counterpart of GRB 000630
  52. GRB 000620, optical observations
  53. GRB000418, HST/STIS Observations
  54. GRB990123: Late-time HST/STIS observations of the host
  55. GRB000620, optical observations
  56. GRB000620 - Optical observations
  57. GRB000620 Optical observations
  58. GRB000620: BeppoSAX WFC and GRBM detection
  59. GRB000607, optical observations
  60. GRB 000615: NIR further observations
  61. GRB000616 optical observations
  62. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  63. GRB000615, further R-band photometry
  64. GRB 000615: NIR observations
  65. GRB000615: BeppoSAX NFI follow-up preliminary analysis
  66. GRB000615, R-band photometry
  67. GRB 000301C: Further Late-Time HST/STIS observations
  68. GRB000528: follow-up X-ray measurements and update of IPN annulus
  69. BeppoSAX X-ray transient/possible GRB000608
  70. GRB000604 - Optical observations
  71. GRB000604, optical observations
  72. GRB000528, optical observations at ESO
  73. GRB 000418: Detection of the Host Galaxy
  74. GRB000604, optical observations, comparison with DPOSS
  75. GRB000528, Radio Observations
  76. X-ray Afterglow of GRB 000529
  77. GRB000529: BeppoSAX NFI follow-up preliminary analysis
  78. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  79. GRB 000528 - WFC measurements
  80. GRB000519, BVRI field photometry
  81. GRB000508B, optical photometry
  82. GRB000508B, BVR field photometry
  83. Possible GRB-related phenomenon
  84. RXTE/ASM and IPN localization of GRB 000508B
  85. GRB000424, UBVRI field photometry
  86. GRB000418, UBVRI field photometry update
  87. GRB000424, optical observations
  88. GRB 000429, optical observation
  89. GRB 000429, UBVRI field photometry
  90. GRB 000418, UBVRI field photometry
  91. GRB 000418, optical observation
  92. GRB 000418, Optical Observation
  93. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  94. GRB 000408, optical observations
  95. Refined IPN error box for GRB000408
  96. GRB 991208, UBVRI field photometry
  97. GRB000408: Optical CCD Observations from MIRO
  98. GRB000408, lotis optical observations
  99. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  100. GRB000408 [IPN Position]

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