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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"

32541 results found.

  1. GRB001204: Optical observations
  2. Confirmation of IPN position for GRB001204
  3. GRB001204, Radio observations
  4. GRB 001105, further optical observations
  5. GRB001120: Gunn-i observations
  6. GRB001109, optical observations
  7. WSRT 4.8 GHz observations of GRB001109
  8. Optical/NIR observations of GRB001109
  9. GRB 001109: deep JHK upper limits
  10. GRB 001109 X-ray afterglow with BeppoSAX
  11. CORRECTION to XMM-Newton observation of GRB001025
  12. GRB001109: Optical observations
  13. GRB001109, R-band optical observations
  14. GRB001109, Radio observations
  15. GRB001105 BVRI field photometry correction
  16. GRB001105, BVRI field photometry
  17. GRB 001105, R-band observation
  18. GRB 991208: HST Imaging of the Host Galaxy
  19. GRB000926: R-image of the host galaxy
  20. GRB 001025B, I-band observations
  21. XMM-Newton observation of GRB001025
  22. GRB001025B, Radio observations
  23. GRB 001025 Optical Observations
  24. GRB 001025A, optical observation
  25. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  26. IPN triangulation of GRB001025
  27. GRB001007: Optical observations
  28. GRB001007, Radio observations
  29. GRB 001018, Possible Radio Afterglow
  30. CORRECTION TO PEAK FLUX OF GRB001018
  31. GRB 000926: Improved Absorber Redshift
  32. V,R,I band observations of GRB000926
  33. The Likely Optical/Infrared Afterglow of GRB 001011
  34. HETE positions added to GCN
  35. GRB 001007, BVR-band observations
  36. GRB001007: Optical observations
  37. CONCAM null result on GRB001005
  38. GRB 000926 : the host galaxy
  39. GRB 000926 Chandra Observation
  40. Public availability of BeppoSAX data of GRB000926
  41. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  42. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  43. GRB000926 - Optical observations
  44. GRB000926 - Optical observations
  45. GRB 000926, Optical Decay
  46. GRB000911: VLT infrared observation
  47. GRB000926 - Optical observations
  48. GRB000926 - Optical observations
  49. GRB 000926: optical observations
  50. GRB 000926, Optical Observations
  51. GRB000926 - Optical observations
  52. GRB000911: optical VLT observations
  53. GRB000926 : increasing optical decay slope
  54. GRB000926 optical observations
  55. GRB000926 - Optical observations
  56. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  57. J and K band observations of GRB 000926
  58. GRB000911 Optical Observations
  59. GRB 000926: Lightcurve Update and Predictions
  60. GRB 000926, optical observation by Oksanen (vsnet-grb)
  61. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  62. GRB000926: Optical observations
  63. GRB 000926: Preliminary R-band Lightcurve
  64. GRB 000926 HST/Chandra TOO Status
  65. Spectroscopic Redshift of GRB 000926
  66. GRB 000926, Optical Observation
  67. GRB000926, radio observations
  68. GRB 000926: Optical candidate
  69. Optical candidate for GRB000926
  70. IPN triangulation of GRB000926
  71. GRB 000911, BVRI field photometry
  72. GRB000911: Corrected coordinates
  73. GRB000911: Sub-millimeter observations
  74. GRB000911: Optical Transient
  75. GRB000911, Radio and Optical observations
  76. GRB000911, Radio observations
  77. GRB000911: Optical observations
  78. False GRB alarm from RXTE/ASM on 8 Sept 2000
  79. GRB 000830: Optical observations
  80. GRB000830: Optical observations
  81. GRB000830, TNG B-band observations
  82. GRB000830: Optical observations
  83. GRB000210, Optical observations
  84. Chandra Position of GRB000210
  85. GRB000830: Optical observations
  86. HST/STIS observations of the host galaxy of GRB 980329
  87. HST/STIS observations of the chaotic environment of GRB 980613
  88. GRB000812, TNG R-band observations
  89. GRB000801 & GRB000730, Gamma Ray Observations
  90. GRB000812, Radio observations
  91. GRB000801, VLT-Antu R-band observations
  92. GRB000301C, UBVI optical observations
  93. GRB000801, Radio Observations
  94. GRB 991208 Host Galaxy Imaging
  95. Updated IPN coordinates for GRB000801
  96. IPN localization of GRB000801
  97. IPN localization of GRB000730B
  98. GRB 990510: Possible detection of a host galaxy
  99. GRB 990510 Host Galaxy Discovery
  100. GRB 000727, optical observations

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