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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"

22912 results found.

  1. GRB000830: Optical observations
  2. IPN triangulation of GRB000830
  3. IPN localization of GRB000820
  4. GRB000812, TNG R-band observations
  5. IPN localization of GRB000812
  6. IPN localization of GRB000811
  7. GRB000801, VLT-Antu R-band observations
  8. GRB 991208 Host Galaxy Imaging
  9. IPN localization of GRB000801
  10. IPN localization of GRB000730B
  11. IPN localization of GRB000730B
  12. IPN localization of GRB000730
  13. GRB 990510: Possible detection of a host galaxy
  14. GRB 990510 Host Galaxy Discovery
  15. IPN localization of GRB000727
  16. GRB 990712: Late time HST/STIS Observations
  17. GRB 991216, HST/STIS observations
  18. GRB000630, optical observations
  19. GRB000630, Revised BVRI Field Photometry
  20. GRB000630, Optical Observations
  21. GRB000630, optical observations
  22. GRB000630, optical observations
  23. GRB000630, BVRI Field Photometry
  24. GRB000630, optical observations
  25. GRB000630: Optical observations
  26. possible optical counterpart of GRB 000630
  27. IPN triangulation of GRB000630
  28. GRB 000620, optical observations
  29. GRB000418, HST/STIS Observations
  30. GRB990123: Late-time HST/STIS observations of the host
  31. GRB000623
  32. GRB000620, optical observations
  33. GRB000615: H-band observations
  34. GRB000620 - Optical observations
  35. GRB000620 Optical observations
  36. IPN annulus for GRB000620
  37. GRB000620: BeppoSAX WFC and GRBM detection
  38. GRB000607, optical observations
  39. GRB 000615: NIR further observations
  40. GRB990123, HST/STIS observations of the host galaxy
  41. GRB000616 optical observations
  42. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  43. GRB000616 [IPN Position]
  44. GRB000615B [IPN Position]
  45. GRB000615, further R-band photometry
  46. GRB 000615: NIR observations
  47. GRB000615: BeppoSAX NFI follow-up preliminary analysis
  48. GRB000615, R-band photometry
  49. GRB 000301C: Further Late-Time HST/STIS observations
  50. GRB000528: follow-up X-ray measurements and update of IPN annulus
  51. Optical Follow-up of GRB000529 Error Box
  52. GRB000604 optical non-detection
  53. GRB000604 - Optical observations
  54. GRB000607, A SHORT, HARD BURST
  55. GRB000604, optical observations
  56. GRB000528, optical observations at ESO
  57. GRB 000604 optical observations
  58. GRB 000418: Detection of the Host Galaxy
  59. GRB000604, optical observations, comparison with DPOSS
  60. GRB000604 [IPN Position]
  61. GRB000528, Radio Observations
  62. X-ray Afterglow of GRB 000529
  63. GRB000529: BeppoSAX NFI follow-up preliminary analysis
  64. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  65. GRB000529: Optical Observations
  66. IPN localization and time history of GRB000528
  67. IPN localization of GRB000529
  68. GRB 000528 - WFC measurements
  69. GRB000519, BVRI field photometry
  70. IPN triangulation of GRB000519
  71. IPN triangulation of GRB000516
  72. Re: GRB000508B : Optical observations
  73. GRB000508B, optical photometry
  74. GRB000508B, BVR field photometry
  75. Possible GRB-related phenomenon
  76. RXTE/ASM and IPN localization of GRB 000508B
  77. GRB000424, UBVRI field photometry
  78. GRB 000424 Optical Observations
  79. GRB000418, UBVRI field photometry update
  80. GRB000424, optical observations
  81. GRB 000429, optical observation
  82. GRB 000429, UBVRI field photometry
  83. IPN localization of GRB000429
  84. GRB 000418, UBVRI field photometry
  85. GRB 000418, optical observation
  86. GRB000424, optical observations
  87. GRB 000418, Optical Observation
  88. IPN error box for GRB000418
  89. GRB000419 [IPN Position]
  90. GRB000416 Optical Observations
  91. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  92. Budget cuts in BeppoSAX operations: impact on GRB observations
  93. GRB 000408, optical observations
  94. GRB 991208, UBVRI field photometry
  95. GRB000408, lotis optical observations
  96. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  97. GRB000301C - Addendum to GCN 623
  98. GRB 000326: Optical Observations
  99. GRB000326, Radio observations
  100. GRB 000307 optical observations

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