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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"

24805 results found.

  1. BeppoSAX NFI Observation of GRB990705
  2. GRB 990705, R-band observations
  3. Infrared and Optical Observations of GRB990705
  4. GRB990704: SAX-NFI results summary
  5. GRB990704 radio and optical observations
  6. GRB990704
  7. GRB990704, optical observations
  8. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  9. Optical Observations of GRB990627
  10. BeppoSAX: GRB990625
  11. Late-time HST/STIS Observation of GRB 990123
  12. Optical Observations of GRB 990506
  13. GRB990527 Optical Observations
  14. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  15. Late Afterglows of GRBs 990510, 990123
  16. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  17. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  18. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  19. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  20. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  21. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  22. radio observations of X-ray/GRB transient field
  23. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  24. Optical report on X-ray/GRB transient
  25. radio detection of X-ray/GRB transient
  26. BeppoSAX: A new fast X-ray transient
  27. GRB 990510: optical observations
  28. GRB 990510: optical linear polarization
  29. GRB 990510: optical observations
  30. GRB990510: X-ray afterglow
  31. GRB 990510: Broad Band Break
  32. GRB 990510: BATSE Observations
  33. GRB 990510: BeppoSAX/GRBM observations
  34. GRB990510 optical observations
  35. GRB 990510 optical observations
  36. GRB 990506 Radio Observations
  37. GRB 990123, optical monitoring
  38. GRB 990506: BATSE Observations
  39. GRB 990506, optical observations
  40. GRB 990506, Optical Observations
  41. GRB 990506 optical observations
  42. GRB 990506, optical observations
  43. GRB 990506, armchair astronomy
  44. GRB 990506, optical observations from +1 to +3 hours
  45. GRB 990506, optical observations
  46. GRB990506 observation plan
  47. IPN localization for GRB990506
  48. GRB990323 PRECISE IPN POSITION
  49. GRB 990316 Optical Observations
  50. GRB 990316 optical observations
  51. GRB990316: simultaneous optical observation
  52. GRB990316 - Optical null results
  53. GRB990308 not a new SGR
  54. GRB 990308a and GRB 990308b
  55. GRB990308, Possible new SGR~0209+70
  56. GRB 990123, Field Photometry
  57. GRB 990217 Optical Observations
  58. BATSE Flight Anomaly
  59. GRB990217: BeppoSAX/GRBM data
  60. GRB990123 observations
  61. GRB990217 Optical observation
  62. GRB990123, Optical Observation
  63. GRB 990123: Discovery of the Probable Host Galaxy
  64. GRB 990123: Reduced HST Images
  65. GRB19990123 observations
  66. GRB 990123: BVRI standards in the field
  67. GRB981220, field photometry
  68. GRB990123, Optical observation
  69. GRB990123, 15-GHz limits
  70. GRB 990123: New Constraints on Possible Foreground Galaxies
  71. GRB990123 Optical Observations
  72. GRB990123, Probability of gravitational lensing
  73. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  74. GRB990123, Preliminary Lens Search Results
  75. On the Lensing Interpretation of GRB 990123
  76. Search for Potential Images of GRB 990123
  77. Search for Potential Images of GRB 990123
  78. GRB990123, Optical BVRI Observations
  79. GRB 990123: near-infrared observations.
  80. GRB990123, OSSE observations
  81. GRB990123: NIR Observation
  82. GRB990123, ASCA X-ray observation of afterglow
  83. "GRB 990123: New BV Observations"
  84. GRB 990123 Optical Follow-Up
  85. GRB 990123: BATSE Observations
  86. GRB990123 Optical Observations
  87. GRB 990123: New Optical Observations, Decay Measure
  88. GRB 990123 Optical Follow-Up
  89. GRB 990123: Possible Gravitationally Lensed Burst?
  90. GRB990123, optical observation
  91. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  92. GRB990123, Optical observation
  93. GRB 990123: Optical Decay Slope
  94. GRB 990123 r-band photometry
  95. GRB 990123 Optical Follow-up
  96. GRB990123, early optical counterpart detection
  97. GRB990123 Optical Observation
  98. Possible identification of SN1999E with GRB980910
  99. Optical Observations of GRB 981220
  100. GRB 981226: radio variable

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