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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"

28082 results found.

  1. Optical report on X-ray/GRB transient
  2. radio detection of X-ray/GRB transient
  3. BeppoSAX: A new fast X-ray transient
  4. GRB 990510: optical observations
  5. GRB 990510: optical linear polarization
  6. GRB 990510: optical observations
  7. GRB990510: X-ray afterglow
  8. GRB 990510: Broad Band Break
  9. GRB 990510: BATSE Observations
  10. GRB 990510: BeppoSAX/GRBM observations
  11. GRB990510 optical observations
  12. GRB 990510 optical observations
  13. GRB 990506 Radio Observations
  14. GRB 990123, optical monitoring
  15. GRB 990506: BATSE Observations
  16. GRB 990506, optical observations
  17. GRB 990506, Optical Observations
  18. GRB 990506 optical observations
  19. GRB 990506, optical observations
  20. GRB 990506, armchair astronomy
  21. GRB 990506, optical observations from +1 to +3 hours
  22. GRB 990506, optical observations
  23. GRB990506 observation plan
  24. IPN localization for GRB990506
  25. GRB990323 PRECISE IPN POSITION
  26. GRB 990316 Optical Observations
  27. GRB 990316 optical observations
  28. GRB990316: simultaneous optical observation
  29. GRB990316 - Optical null results
  30. GRB990308 not a new SGR
  31. GRB 990308a and GRB 990308b
  32. GRB990308, Possible new SGR~0209+70
  33. GRB 990123, Field Photometry
  34. GRB 990217 Optical Observations
  35. BATSE Flight Anomaly
  36. GRB990217: BeppoSAX/GRBM data
  37. GRB990123 observations
  38. GRB990217 Optical observation
  39. GRB990123, Optical Observation
  40. GRB 990123: Discovery of the Probable Host Galaxy
  41. GRB 990123: Reduced HST Images
  42. GRB19990123 observations
  43. GRB 990123: BVRI standards in the field
  44. GRB981220, field photometry
  45. GRB990123, Optical observation
  46. GRB990123, 15-GHz limits
  47. GRB 990123: New Constraints on Possible Foreground Galaxies
  48. GRB990123 Optical Observations
  49. GRB990123, Probability of gravitational lensing
  50. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  51. GRB990123, Preliminary Lens Search Results
  52. On the Lensing Interpretation of GRB 990123
  53. Search for Potential Images of GRB 990123
  54. Search for Potential Images of GRB 990123
  55. GRB990123, Optical BVRI Observations
  56. GRB 990123: near-infrared observations.
  57. GRB990123, OSSE observations
  58. GRB990123: NIR Observation
  59. GRB990123, ASCA X-ray observation of afterglow
  60. "GRB 990123: New BV Observations"
  61. GRB 990123 Optical Follow-Up
  62. GRB 990123: BATSE Observations
  63. GRB990123 Optical Observations
  64. GRB 990123: New Optical Observations, Decay Measure
  65. GRB 990123 Optical Follow-Up
  66. GRB 990123: Possible Gravitationally Lensed Burst?
  67. GRB990123, optical observation
  68. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  69. GRB990123, Optical observation
  70. GRB 990123: Optical Decay Slope
  71. GRB 990123 r-band photometry
  72. GRB 990123 Optical Follow-up
  73. GRB990123, early optical counterpart detection
  74. GRB990123 Optical Observation
  75. Possible identification of SN1999E with GRB980910
  76. Optical Observations of GRB 981220
  77. GRB 981226: radio variable
  78. GRB981220
  79. GRB981220, Correction to GCN 179
  80. GRB 981220 Optical observations
  81. GRB 981226 Optical Observations
  82. GRB 981220 and GRB 981226, optical observations
  83. GRB981226 Optical Observations
  84. GRB981226 BeppoSAX follow up
  85. GRB 981226
  86. GRB 981226 optical observations
  87. GRB981220 B, R and I band observations
  88. Optical Observations of GRB981226
  89. GRB 981220:Optical Observations
  90. GRB 981226 optical observations
  91. GRB 981220
  92. GRB 981220, radio observations
  93. GRB981220 I-band Observations
  94. GRB 981220
  95. GRB 980326/Host Galaxy
  96. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  97. BeppoSAX NFI Observation of GRB980425
  98. GRB980329 R,I flux calibration and R,I,K upper limits
  99. GRB980425 Optical Follow-up
  100. GRB 980923 BATSE Observations

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Download all Circulars as a .tar.gz archive (updated once a day):
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