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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"

24664 results found.

  1. GRB 001212 possible OA in 2MASS
  2. IPN triangulation of GRB001212
  3. Confirmation of IPN position for GRB001204
  4. IPN triangulation of GRB001204 (short/hard)
  5. GRB001120, optical observations
  6. WSRT 4.8 GHz observations of GRB001109
  7. IPN triangulation of GRB001120
  8. GRB 001109: deep JHK upper limits
  9. GRB 001109 X-ray afterglow with BeppoSAX
  10. CORRECTION to XMM-Newton observation of GRB001025
  11. GRB001109, Radio observations
  12. GRB001105 BVRI field photometry correction
  13. GRB001105, BVRI field photometry
  14. IPN TRIANGULATION OF GRB001105
  15. GRB 001025B, Optical obervations
  16. GRB 991208: HST Imaging of the Host Galaxy
  17. GRB 001025B, I-band observations
  18. XMM-Newton observation of GRB001025
  19. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  20. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  21. GRB001007: Optical observations
  22. ASM Localization of GRB 001025
  23. GRB001007, Radio observations
  24. GRB 001018, Possible Radio Afterglow
  25. GRB001018, Gamma Ray Observations
  26. IPN TRIANGULATION OF GRB001019
  27. IPN TRIANGULATION OF GRB001018
  28. IPN TRIANGULATION OF GRB 001017
  29. V,R,I band observations of GRB000926
  30. HETE positions added to GCN
  31. GRB000926 - Amateur Optical Observations
  32. CONCAM null result on GRB001005
  33. IPN triangulation of GRB001005
  34. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  35. GRB000926 - Optical observations
  36. GRB000926 - Optical observations
  37. GRB 000926, Optical Decay
  38. GRB000911: VLT infrared observation
  39. GRB 000926, Optical Observations
  40. GRB000926 K'-band Observation
  41. J and K band observations of GRB 000926
  42. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  43. CONCAM crude optical limits before and after GRB000926
  44. GRB 000926: Preliminary R-band Lightcurve
  45. Spectroscopic Redshift of GRB 000926
  46. GRB 000926: Optical candidate
  47. Optical candidate for GRB000926
  48. GRB 000911, BVRI field photometry
  49. GRB000911, Radio and Optical observations
  50. GRB000911: Optical observations
  51. GRB000830, BVRI field photometry
  52. GRB000210, Optical observations
  53. "Snapshot" afterglow IDs and GRB 000830
  54. GRB000730, Gamma Ray Observations
  55. GRB000812, Radio observations
  56. GRB000801, Gamma Ray Observations
  57. GRB000801, VLT-Antu R-band observations
  58. GRB 991208 Host Galaxy Imaging
  59. IPN localization of GRB000730B
  60. GRB 990510: Possible detection of a host galaxy
  61. GRB 990510 Host Galaxy Discovery
  62. IPN localization of GRB000727
  63. GRB 990712: Late time HST/STIS Observations
  64. GRB 991216, HST/STIS observations
  65. GRB000620, Radio Observations
  66. GRB000630, optical observations
  67. GRB000630, Revised BVRI Field Photometry
  68. GRB000630, Optical Observations
  69. GRB000630, optical observations
  70. GRB000630, optical observations
  71. GRB000630, BVRI Field Photometry
  72. GRB000630, optical observations
  73. GRB000630: Optical observations
  74. GRB000630, Radio Observations
  75. possible optical counterpart of GRB 000630
  76. GRB 000620, optical observations
  77. GRB000418, HST/STIS Observations
  78. GRB990123: Late-time HST/STIS observations of the host
  79. GRB000620, optical observations
  80. GRB000615: H-band observations
  81. GRB990308, HST/STIS observations of the host galaxy
  82. GRB000620 - Optical observations
  83. GRB000620 Optical observations
  84. GRB000620: BeppoSAX WFC and GRBM detection
  85. GRB000607, optical observations
  86. GRB 000615: NIR further observations
  87. GRB990123, HST/STIS observations of the host galaxy
  88. GRB000616 optical observations
  89. GRB 000615, near-infrared observations
  90. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  91. GRB000615, further R-band photometry
  92. GRB 000615: NIR observations
  93. GRB000615: BeppoSAX NFI follow-up preliminary analysis
  94. GRB000615, R-band photometry
  95. The Hosts of GRB 980703 and GRB 971214
  96. GRB 000301C: Further Late-Time HST/STIS observations
  97. GRB000528: follow-up X-ray measurements and update of IPN annulus
  98. GRB980519, HST/STIS observations of the host galaxy
  99. GRB000604 optical non-detection
  100. GRB000604 - Optical observations

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