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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"

23630 results found.

  1. BeppoSAX NFI Observation of GRB990705
  2. BeppoSAX NFI Observation of GRB990705
  3. Updated IPN localization of GRB990705
  4. IPN localization of GRB990704
  5. IPN localization of GRB990705
  6. GRB 990705, radio observations
  7. BeppoSAX GRB990705: possible X-ray afterglow
  8. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  9. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  10. Optical Observations of GRB990627
  11. GRB 990627, radio observations
  12. BeppoSAX: GRB990625
  13. Late-time HST/STIS Observation of GRB 990123
  14. GRB 990506 Radio Transient
  15. GRB990527 Optical Observations
  16. Late Afterglows of GRBs 990510, 990123
  17. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  18. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  19. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  20. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  21. BeppoSAX: A new fast X-ray transient
  22. GRB990510: photometric and spectroscopic observations with the VLT
  23. GRB 990506 R band observations
  24. GRB990510: X-ray afterglow
  25. GRB 990510: optical observation
  26. GRB 990510: Broad Band Break
  27. GRB990510 optical observations
  28. IPN localization of GRB990510
  29. GRB 990506 Radio Observations
  30. GRB 990506: BATSE Observations
  31. GRB 990506 optical observations
  32. GRB 990506, optical observations
  33. Refined IPN error box for GRB990506
  34. GRB 990506, optical observations
  35. IPN localization for GRB990506
  36. IPN localization of GRB990427
  37. GRB981220 VLBA observations
  38. GRB980425 Optical observations of exponential decline at late time
  39. GRB990321 IPN TRIANGULATION
  40. GRB990316: simultaneous optical observation
  41. ASM/IPN error box for GRB 990308 (BATSE #7457)
  42. GRB 990308a and GRB 990308b
  43. GRB990308 (Trig. 7457), optical observations
  44. GRB990308, Possible new SGR~0209+70
  45. GRB981220, IPN localization
  46. GRB 990217, radio observations
  47. BATSE Resumes Normal Operations
  48. GRB990123 observations
  49. GRB990217 Optical observation
  50. GRB990123, Optical observation
  51. GRB 990123: Publicly available reduced HST images
  52. GRB990123, Upcoming HST Service Observations
  53. GRB990123 Optical Observations
  54. GRB990123, Probability of gravitational lensing
  55. GRB 990123: Continued Radio Observations
  56. GRB990123, Preliminary Lens Search Results
  57. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  58. On the Lensing Interpretation of GRB 990123
  59. Search for Potential Images of GRB 990123
  60. GRB990123, Optical BVRI Observations
  61. GRB 990123: near-infrared observations.
  62. GRB990123, OSSE observations
  63. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  64. GRB 990123 Spectroscopic Redshifts
  65. GRB 990123 optical observations
  66. GRB990123 optical observations
  67. GRB990123, Optical observation
  68. GRB 990123: Optical Decay Slope
  69. GRB990123, early optical counterpart detection
  70. GRB990123 Optical Observation
  71. GRB 990123: Bright New Source, Possible Optical Transient
  72. Possible identification of SN1999E with GRB980910
  73. Optical Observations of GRB 981220
  74. GRB981220
  75. GRB981220, Correction to GCN 179
  76. GRB 981220 Optical observations
  77. GRB 981226
  78. GRB 981220
  79. GRB 981220, radio observations
  80. GRB981226 Optical Observation
  81. GRB 981220: BeppoSAX/GRBM results
  82. GRB981220 I-band Observations
  83. GRB981220 Optical Observations
  84. GRB 981220
  85. GRB 980326/Host Galaxy
  86. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  87. GRB 980923 BATSE Observations
  88. GRB970508 optical observations
  89. Optical Observations of the Host Galaxy of GRB 980519
  90. GRB980519, Optical Observations
  91. GRB980703 H-band Observations
  92. GRB980703: LOTIS observation at early times
  93. GRB 980703: ASM Position & Intensity
  94. GRB980519 observation report
  95. GRB980703 optical followup
  96. GRB980613, optical observations
  97. GRB 980613: BATSE Observations
  98. Discovery of a new SGR source, SGR1627-41
  99. GRB 980519 Optical Observations
  100. GRB 980519 Optical Observations

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