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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"

28065 results found.

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

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