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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"

37512 results found.

  1. GRB 001212 optical observation
  2. GRB 001212 possible OA in 2MASS
  3. GRB 001212 possible OA
  4. IPN triangulation of GRB001212
  5. Confirmation of IPN position for GRB001204
  6. IPN triangulation of GRB001204 (short/hard)
  7. GRB 001105, further optical observations
  8. GRB001120: Gunn-i observations
  9. GRB001120: Optical observations
  10. GRB001109, optical observations
  11. GRB001120, optical observations
  12. IPN triangulation of GRB001120
  13. Optical/NIR observations of GRB001109
  14. GRB 001109: deep JHK upper limits
  15. GRB 001109 X-ray afterglow with BeppoSAX
  16. GRB001109: Optical observations
  17. GRB001109: BeppoSAX/NFI Observations
  18. GRB001109, R-band optical observations
  19. GRB001109, Radio observations
  20. BeppoSAX ALERT: GRB001109
  21. GRB001105 BVRI field photometry correction
  22. GRB001105, BVRI field photometry
  23. GRB 001105, R-band observation
  24. IPN TRIANGULATION OF GRB001105
  25. GRB 001025B, Optical obervations
  26. GRB 991208: HST Imaging of the Host Galaxy
  27. GRB000926: R-image of the host galaxy
  28. GRB 001025B, I-band observations
  29. GRB 001025 Optical Observations
  30. GRB 001025A, optical observation
  31. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  32. IPN triangulation of GRB001025
  33. ASM Localization of GRB 001025
  34. GRB001007, Radio observations
  35. IPN TRIANGULATION OF GRB001020
  36. GRB001019, Optical Observations
  37. GRB 001018, Possible Radio Afterglow
  38. GRB001018, Gamma Ray Observations
  39. IPN TRIANGULATION OF GRB001019
  40. IPN TRIANGULATION OF GRB001018
  41. IPN TRIANGULATION OF GRB 001017
  42. GRB 000926: Improved Absorber Redshift
  43. V,R,I band observations of GRB000926
  44. The Likely Optical/Infrared Afterglow of GRB 001011
  45. HETE positions added to GCN
  46. BeppoSAX ALERT: GRB001011
  47. GRB 001007, BVR-band observations
  48. GRB000926 - Amateur Optical Observations
  49. CONCAM null result on GRB001005
  50. IPN triangulation of GRB001007
  51. GRB 000926 : the host galaxy
  52. IPN triangulation of GRB001005
  53. GRB 000926 Chandra Observation
  54. IPN triangulation of GRB 001004
  55. Public availability of BeppoSAX data of GRB000926
  56. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  57. GRB 000926, Optical Decay
  58. GRB000926 - Optical observations
  59. GRB000926 - Optical observations
  60. GRB 000926: optical observations
  61. GRB 000926, Optical Observations
  62. GRB000926 K'-band Observation
  63. GRB000926 : increasing optical decay slope
  64. GRB000926 optical observations
  65. GRB000926 - Optical observations
  66. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  67. J and K band observations of GRB 000926
  68. GRB 000926: Lightcurve Update and Predictions
  69. GRB 000926, optical observation by Oksanen (vsnet-grb)
  70. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  71. CONCAM crude optical limits before and after GRB000926
  72. GRB 000926: Preliminary R-band Lightcurve
  73. GRB 000926 HST/Chandra TOO Status
  74. Spectroscopic Redshift of GRB 000926
  75. GRB 000926, Optical Observation
  76. GRB 000926: Optical candidate
  77. Optical candidate for GRB000926
  78. IPN triangulation of GRB000926
  79. GRB 000911, BVRI field photometry
  80. GRB000911: Sub-millimeter observations
  81. IPN triangulation of GRB000925
  82. IPN triangulation of GRB000911
  83. IPN triangulation of GRB000910
  84. False GRB alarm from RXTE/ASM on 8 Sept 2000
  85. GRB 000830: Optical observations
  86. GRB000830: Optical observations
  87. GRB000830, TNG B-band observations
  88. GRB000830, BVRI field photometry
  89. GRB000830: Optical observations
  90. GRB000210, Optical observations
  91. Chandra Position of GRB000210
  92. "Snapshot" afterglow IDs and GRB 000830
  93. IPN triangulation of GRB000830
  94. HST/STIS observations of the host galaxy of GRB 980329
  95. HST/STIS observations of the chaotic environment of GRB 980613
  96. IPN localization of GRB000820
  97. GRB000801 & GRB000730, Gamma Ray Observations
  98. GRB000730, Gamma Ray Observations
  99. GRB000812, Radio observations
  100. IPN localization of GRB000812

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