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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"

36681 results found.

  1. IPN triangulation of GRB001025
  2. ASM Localization of GRB 001025
  3. GRB001007, Radio observations
  4. IPN TRIANGULATION OF GRB001020
  5. GRB001019, Optical Observations
  6. GRB 001018, Possible Radio Afterglow
  7. GRB001018, Gamma Ray Observations
  8. IPN TRIANGULATION OF GRB001019
  9. IPN TRIANGULATION OF GRB001018
  10. IPN TRIANGULATION OF GRB 001017
  11. GRB 000926: Improved Absorber Redshift
  12. V,R,I band observations of GRB000926
  13. The Likely Optical/Infrared Afterglow of GRB 001011
  14. HETE positions added to GCN
  15. BeppoSAX ALERT: GRB001011
  16. GRB 001007, BVR-band observations
  17. GRB000926 - Amateur Optical Observations
  18. CONCAM null result on GRB001005
  19. IPN triangulation of GRB001007
  20. GRB 000926 : the host galaxy
  21. IPN triangulation of GRB001005
  22. GRB 000926 Chandra Observation
  23. IPN triangulation of GRB 001004
  24. Public availability of BeppoSAX data of GRB000926
  25. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  26. GRB 000926, Optical Decay
  27. GRB000926 - Optical observations
  28. GRB000926 - Optical observations
  29. GRB 000926: optical observations
  30. GRB 000926, Optical Observations
  31. GRB000926 K'-band Observation
  32. GRB000926 : increasing optical decay slope
  33. GRB000926 optical observations
  34. GRB000926 - Optical observations
  35. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  36. J and K band observations of GRB 000926
  37. GRB 000926: Lightcurve Update and Predictions
  38. GRB 000926, optical observation by Oksanen (vsnet-grb)
  39. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  40. CONCAM crude optical limits before and after GRB000926
  41. GRB 000926: Preliminary R-band Lightcurve
  42. GRB 000926 HST/Chandra TOO Status
  43. Spectroscopic Redshift of GRB 000926
  44. GRB 000926, Optical Observation
  45. GRB 000926: Optical candidate
  46. Optical candidate for GRB000926
  47. IPN triangulation of GRB000926
  48. GRB 000911, BVRI field photometry
  49. GRB000911: Sub-millimeter observations
  50. IPN triangulation of GRB000925
  51. IPN triangulation of GRB000911
  52. IPN triangulation of GRB000910
  53. False GRB alarm from RXTE/ASM on 8 Sept 2000
  54. GRB 000830: Optical observations
  55. GRB000830: Optical observations
  56. GRB000830, TNG B-band observations
  57. GRB000830, BVRI field photometry
  58. GRB000830: Optical observations
  59. GRB000210, Optical observations
  60. Chandra Position of GRB000210
  61. "Snapshot" afterglow IDs and GRB 000830
  62. IPN triangulation of GRB000830
  63. HST/STIS observations of the host galaxy of GRB 980329
  64. HST/STIS observations of the chaotic environment of GRB 980613
  65. IPN localization of GRB000820
  66. GRB000801 & GRB000730, Gamma Ray Observations
  67. GRB000730, Gamma Ray Observations
  68. GRB000812, Radio observations
  69. IPN localization of GRB000812
  70. IPN localization of GRB000811
  71. GRB000801, Gamma Ray Observations
  72. GRB000801, VLT-Antu R-band observations
  73. GRB 991208 Host Galaxy Imaging
  74. Updated IPN coordinates for GRB000801
  75. IPN localization of GRB000801
  76. IPN localization of GRB000730B
  77. IPN localization of GRB000730B
  78. IPN localization of GRB000730
  79. GRB 990510: Possible detection of a host galaxy
  80. GRB 990510 Host Galaxy Discovery
  81. GRB 000727, optical observations
  82. IPN localization of GRB000727
  83. GRB 990705, HST/STIS observations of the host galaxy
  84. GRB 990712: Late time HST/STIS Observations
  85. GRB 991216, HST/STIS observations
  86. GRB981226, HST/STIS observations of the host galaxy
  87. GRB 000630: Detection of the Optical Afterglow
  88. GRB000630, Revised BVRI Field Photometry
  89. GRB000630, Optical Observations
  90. GRB000630, optical observations
  91. GRB000630, BVRI Field Photometry
  92. GRB000630, optical observations
  93. GRB000630: Optical observations
  94. possible optical counterpart of GRB 000630
  95. IPN triangulation of GRB000630
  96. GRB 000623, optical observations
  97. GRB 000620, optical observations
  98. GRB000418, HST/STIS Observations
  99. GRB990123: Late-time HST/STIS observations of the host
  100. GRB 990506, HST/STIS Observations of the Host Galaxy

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