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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"

37503 results found.

  1. GRB001109, optical observations
  2. GRB001120, optical observations
  3. IPN triangulation of GRB001120
  4. Optical/NIR observations of GRB001109
  5. GRB 001109: deep JHK upper limits
  6. GRB 001109 X-ray afterglow with BeppoSAX
  7. GRB001109: Optical observations
  8. GRB001109: BeppoSAX/NFI Observations
  9. GRB001109, R-band optical observations
  10. GRB001109, Radio observations
  11. BeppoSAX ALERT: GRB001109
  12. GRB001105 BVRI field photometry correction
  13. GRB001105, BVRI field photometry
  14. GRB 001105, R-band observation
  15. IPN TRIANGULATION OF GRB001105
  16. GRB 001025B, Optical obervations
  17. GRB 991208: HST Imaging of the Host Galaxy
  18. GRB000926: R-image of the host galaxy
  19. GRB 001025B, I-band observations
  20. GRB 001025 Optical Observations
  21. GRB 001025A, optical observation
  22. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  23. IPN triangulation of GRB001025
  24. ASM Localization of GRB 001025
  25. GRB001007, Radio observations
  26. IPN TRIANGULATION OF GRB001020
  27. GRB001019, Optical Observations
  28. GRB 001018, Possible Radio Afterglow
  29. GRB001018, Gamma Ray Observations
  30. IPN TRIANGULATION OF GRB001019
  31. IPN TRIANGULATION OF GRB001018
  32. IPN TRIANGULATION OF GRB 001017
  33. GRB 000926: Improved Absorber Redshift
  34. V,R,I band observations of GRB000926
  35. The Likely Optical/Infrared Afterglow of GRB 001011
  36. HETE positions added to GCN
  37. BeppoSAX ALERT: GRB001011
  38. GRB 001007, BVR-band observations
  39. GRB000926 - Amateur Optical Observations
  40. CONCAM null result on GRB001005
  41. IPN triangulation of GRB001007
  42. GRB 000926 : the host galaxy
  43. IPN triangulation of GRB001005
  44. GRB 000926 Chandra Observation
  45. IPN triangulation of GRB 001004
  46. Public availability of BeppoSAX data of GRB000926
  47. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  48. GRB 000926, Optical Decay
  49. GRB000926 - Optical observations
  50. GRB000926 - Optical observations
  51. GRB 000926: optical observations
  52. GRB 000926, Optical Observations
  53. GRB000926 K'-band Observation
  54. GRB000926 : increasing optical decay slope
  55. GRB000926 optical observations
  56. GRB000926 - Optical observations
  57. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  58. J and K band observations of GRB 000926
  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. CONCAM crude optical limits before and after GRB000926
  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. GRB 000926: Optical candidate
  68. Optical candidate for GRB000926
  69. IPN triangulation of GRB000926
  70. GRB 000911, BVRI field photometry
  71. GRB000911: Sub-millimeter observations
  72. IPN triangulation of GRB000925
  73. IPN triangulation of GRB000911
  74. IPN triangulation of GRB000910
  75. False GRB alarm from RXTE/ASM on 8 Sept 2000
  76. GRB 000830: Optical observations
  77. GRB000830: Optical observations
  78. GRB000830, TNG B-band observations
  79. GRB000830, BVRI field photometry
  80. GRB000830: Optical observations
  81. GRB000210, Optical observations
  82. Chandra Position of GRB000210
  83. "Snapshot" afterglow IDs and GRB 000830
  84. IPN triangulation of GRB000830
  85. HST/STIS observations of the host galaxy of GRB 980329
  86. HST/STIS observations of the chaotic environment of GRB 980613
  87. IPN localization of GRB000820
  88. GRB000801 & GRB000730, Gamma Ray Observations
  89. GRB000730, Gamma Ray Observations
  90. GRB000812, Radio observations
  91. IPN localization of GRB000812
  92. IPN localization of GRB000811
  93. GRB000801, Gamma Ray Observations
  94. GRB000801, VLT-Antu R-band observations
  95. GRB 991208 Host Galaxy Imaging
  96. Updated IPN coordinates for GRB000801
  97. IPN localization of GRB000801
  98. IPN localization of GRB000730B
  99. IPN localization of GRB000730B
  100. IPN localization of GRB000730

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