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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"

28068 results found.

  1. Correction to Chandra Position of GRB000210 afterglow
  2. Optical observations of the Chandra X-ray source for GRB000210
  3. Chandra Observations of GRB000210 X-ray Afterglow
  4. GRB000210: possible afterglow detection with BeppoSAX NFI
  5. GRB000210: BeppoSAX GRBM and WFC Detection
  6. GRB 000131 Optical Observations
  7. GRB 991208, radio observations
  8. GRB000126, optical observations
  9. GRB 000115 Optical observations
  10. BATSE Observations of GRB000115
  11. Second RXTE Observation of GRB 000115
  12. GRB991216 late optical observation
  13. GRB 991216 VLBA Observations
  14. GRB 991216: J band spectrophotometry
  15. GRB 991216: Detection of the Host and/or Absorber Galaxy
  16. GRB 991216 RXTE ASM Observations
  17. Chandra observation of the X-ray afterglow of GRB991216
  18. GRB 991216 Optical spectroscopy/imaging
  19. GRB991216 Optical and IR observations
  20. GRB991216 radio observations
  21. GRB991216 Optical and infrared observations of Beethoven Burst
  22. GRB 991216 Radio Observations
  23. GRB 991208 Infrared Detection
  24. GRB 991216--Summary of RXTE Observations
  25. GRB 991216, Optical Afterglow
  26. GRB991216 Optical Observations
  27. R-band Observations of GRB991208 at TNG
  28. GRB 991208 Keck Spectroscopy
  29. GRB991208 - millimeter detection
  30. GRB 991208, Optical Observation
  31. GRB991208, optical observations
  32. GRB 991208 - OVRO detection
  33. GRB 991208 Optical Decay
  34. GRB 991208 optical observations
  35. GRB 991208 optical observations
  36. GRB 991208: Radio Observations
  37. GRB991106: BeppoSAX/BATSE results
  38. GRB 991106, optical observations
  39. GRB991106: the first BeppoSAX short GRB detection?
  40. GRB991105: SAX-GRBM/-WFC detection
  41. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  42. GRB 991014 - BeppoSAX NFI observations
  43. GRB 991014, Optical Observations
  44. GRB 990915 optical observations
  45. GRB990907: BeppoSAX follow up and X-ray afterglow
  46. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  47. GRB 990712 Late Optical Decay and Host Galaxy
  48. GRB 990712, Optical Observation
  49. GRB990806 BeppoSAX follow up
  50. GRB 990806 Optical observations
  51. GRB990806: possible X-ray afterglow, BeppoSAX
  52. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  53. BeppoSAX NFI Observation of GRB990705
  54. BeppoSAX NFI Observation of GRB990705
  55. Updated Astrometry for the IR Counterpart of GRB990705
  56. Infrared and Optical Observations of GRB990705
  57. GRB 990705, radio observations
  58. GRB990704: SAX-NFI results summary
  59. BeppoSAX GRB990705: possible X-ray afterglow
  60. GRB990704, optical observations
  61. GRB990704: possible X-ray afterglow
  62. GRB990704: BeppoSAX detection
  63. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  64. GRB 990627, radio observations
  65. GRB 990506 - clarification to GCN 352
  66. GRB 990506 Radio Transient
  67. Late Afterglows of GRBs 990510, 990123
  68. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  69. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  70. radio detection of X-ray/GRB transient
  71. GRB 990506 R band observations
  72. GRB990510: X-ray afterglow
  73. GRB 990510: Broad Band Break
  74. GRB990510: NFI X-ray source
  75. GRB 990506: BATSE Observations
  76. GRB 990506, optical observations
  77. GRB 990506, optical observations from +1 to +3 hours
  78. IPN localization for GRB990506
  79. GRB981220 VLBA observations
  80. GRB990321 IPN TRIANGULATION
  81. GRB 990316 Optical Observations
  82. GRB990316: simultaneous optical observation
  83. ASM/IPN error box for GRB 990308 (BATSE #7457)
  84. GRB 981220, radio observations
  85. GRB990123, Optical Observation
  86. GRB 990123: Discovery of the Probable Host Galaxy
  87. GRB19990123 observations
  88. GRB 990123 NOT Spectrum Update
  89. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  90. GRB990123, 15-GHz limits
  91. GRB 990123: New Constraints on Possible Foreground Galaxies
  92. GRB990123 Optical Observations
  93. GRB990123, Probability of gravitational lensing
  94. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  95. GRB 990123: Continued Radio Observations
  96. GRB990123, Preliminary Lens Search Results
  97. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  98. GRB990123, ASCA X-ray observation of afterglow
  99. GRB 990123 Optical Follow-Up
  100. GRB 990123; Addendum to GCN 223

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