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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"

24873 results found.

  1. IPN TRIANGULATION OF GRB010115
  2. IPN TRIANGULATION OF GRB010109
  3. IPN TRIANGULATION OF GRB010109
  4. IPN triangulation of GRB010104
  5. IPN triangulation of GRB010103
  6. H band observation of GRB 001212
  7. IPN triangulation of GRB001219
  8. GRB 001212 Optical Observation
  9. GRB 001212 Optical Observation
  10. GRB 001212 possible OA in 2MASS
  11. IPN triangulation of GRB001212
  12. Confirmation of IPN position for GRB001204
  13. IPN triangulation of GRB001204 (short/hard)
  14. GRB001120, optical observations
  15. WSRT 4.8 GHz observations of GRB001109
  16. IPN triangulation of GRB001120
  17. GRB 001109: deep JHK upper limits
  18. GRB 001109 X-ray afterglow with BeppoSAX
  19. CORRECTION to XMM-Newton observation of GRB001025
  20. GRB001109, Radio observations
  21. GRB001105 BVRI field photometry correction
  22. GRB001105, BVRI field photometry
  23. IPN TRIANGULATION OF GRB001105
  24. GRB 001025B, Optical obervations
  25. GRB 991208: HST Imaging of the Host Galaxy
  26. GRB 001025B, I-band observations
  27. XMM-Newton observation of GRB001025
  28. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  29. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  30. GRB001007: Optical observations
  31. ASM Localization of GRB 001025
  32. GRB001007, Radio observations
  33. GRB 001018, Possible Radio Afterglow
  34. GRB001018, Gamma Ray Observations
  35. IPN TRIANGULATION OF GRB001019
  36. IPN TRIANGULATION OF GRB001018
  37. IPN TRIANGULATION OF GRB 001017
  38. V,R,I band observations of GRB000926
  39. HETE positions added to GCN
  40. GRB000926 - Amateur Optical Observations
  41. CONCAM null result on GRB001005
  42. IPN triangulation of GRB001005
  43. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  44. GRB000926 - Optical observations
  45. GRB000926 - Optical observations
  46. GRB 000926, Optical Decay
  47. GRB000911: VLT infrared observation
  48. GRB 000926, Optical Observations
  49. GRB000926 K'-band Observation
  50. J and K band observations of GRB 000926
  51. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  52. CONCAM crude optical limits before and after GRB000926
  53. GRB 000926: Preliminary R-band Lightcurve
  54. Spectroscopic Redshift of GRB 000926
  55. GRB 000926: Optical candidate
  56. Optical candidate for GRB000926
  57. GRB 000911, BVRI field photometry
  58. GRB000911, Radio and Optical observations
  59. GRB000911: Optical observations
  60. GRB000830, BVRI field photometry
  61. GRB000210, Optical observations
  62. "Snapshot" afterglow IDs and GRB 000830
  63. GRB000730, Gamma Ray Observations
  64. GRB000812, Radio observations
  65. GRB000801, Gamma Ray Observations
  66. GRB000801, VLT-Antu R-band observations
  67. GRB 991208 Host Galaxy Imaging
  68. IPN localization of GRB000730B
  69. GRB 990510: Possible detection of a host galaxy
  70. GRB 990510 Host Galaxy Discovery
  71. IPN localization of GRB000727
  72. GRB 990712: Late time HST/STIS Observations
  73. GRB 991216, HST/STIS observations
  74. GRB000620, Radio Observations
  75. GRB000630, optical observations
  76. GRB000630, Revised BVRI Field Photometry
  77. GRB000630, Optical Observations
  78. GRB000630, optical observations
  79. GRB000630, optical observations
  80. GRB000630, BVRI Field Photometry
  81. GRB000630, optical observations
  82. GRB000630: Optical observations
  83. GRB000630, Radio Observations
  84. possible optical counterpart of GRB 000630
  85. GRB 000620, optical observations
  86. GRB000418, HST/STIS Observations
  87. GRB990123: Late-time HST/STIS observations of the host
  88. GRB000620, optical observations
  89. GRB000615: H-band observations
  90. GRB990308, HST/STIS observations of the host galaxy
  91. GRB000620 - Optical observations
  92. GRB000620 Optical observations
  93. GRB000620: BeppoSAX WFC and GRBM detection
  94. GRB000607, optical observations
  95. GRB 000615: NIR further observations
  96. GRB990123, HST/STIS observations of the host galaxy
  97. GRB000616 optical observations
  98. GRB 000615, near-infrared observations
  99. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  100. GRB000615, further R-band photometry

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