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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"

24871 results found.

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

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