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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"

27784 results found.

  1. radio observations of X-ray/GRB transient field
  2. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  3. Optical report on X-ray/GRB transient
  4. radio detection of X-ray/GRB transient
  5. BeppoSAX: A new fast X-ray transient
  6. GRB 990510: optical observations
  7. GRB 990510: optical linear polarization
  8. GRB 990510: optical observations
  9. GRB990510: X-ray afterglow
  10. GRB 990510: Broad Band Break
  11. GRB 990510: BATSE Observations
  12. GRB 990510: BeppoSAX/GRBM observations
  13. GRB990510 optical observations
  14. GRB 990510 optical observations
  15. GRB 990506 Radio Observations
  16. GRB 990123, optical monitoring
  17. GRB 990506: BATSE Observations
  18. GRB 990506, optical observations
  19. GRB 990506, Optical Observations
  20. GRB 990506 optical observations
  21. GRB 990506, optical observations
  22. GRB 990506, armchair astronomy
  23. GRB 990506, optical observations from +1 to +3 hours
  24. GRB 990506, optical observations
  25. GRB990506 observation plan
  26. IPN localization for GRB990506
  27. GRB990323 PRECISE IPN POSITION
  28. GRB 990316 Optical Observations
  29. GRB 990316 optical observations
  30. GRB990316: simultaneous optical observation
  31. GRB990316 - Optical null results
  32. GRB990308 not a new SGR
  33. GRB 990308a and GRB 990308b
  34. GRB990308, Possible new SGR~0209+70
  35. GRB 990123, Field Photometry
  36. GRB 990217 Optical Observations
  37. BATSE Flight Anomaly
  38. GRB990217: BeppoSAX/GRBM data
  39. GRB990123 observations
  40. GRB990217 Optical observation
  41. GRB990123, Optical Observation
  42. GRB 990123: Discovery of the Probable Host Galaxy
  43. GRB 990123: Reduced HST Images
  44. GRB19990123 observations
  45. GRB 990123: BVRI standards in the field
  46. GRB981220, field photometry
  47. GRB990123, Optical observation
  48. GRB990123, 15-GHz limits
  49. GRB 990123: New Constraints on Possible Foreground Galaxies
  50. GRB990123 Optical Observations
  51. GRB990123, Probability of gravitational lensing
  52. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  53. GRB990123, Preliminary Lens Search Results
  54. On the Lensing Interpretation of GRB 990123
  55. Search for Potential Images of GRB 990123
  56. Search for Potential Images of GRB 990123
  57. GRB990123, Optical BVRI Observations
  58. GRB 990123: near-infrared observations.
  59. GRB990123, OSSE observations
  60. GRB990123: NIR Observation
  61. GRB990123, ASCA X-ray observation of afterglow
  62. "GRB 990123: New BV Observations"
  63. GRB 990123 Optical Follow-Up
  64. GRB 990123: BATSE Observations
  65. GRB990123 Optical Observations
  66. GRB 990123: New Optical Observations, Decay Measure
  67. GRB 990123 Optical Follow-Up
  68. GRB 990123: Possible Gravitationally Lensed Burst?
  69. GRB990123, optical observation
  70. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  71. GRB990123, Optical observation
  72. GRB 990123: Optical Decay Slope
  73. GRB 990123 r-band photometry
  74. GRB 990123 Optical Follow-up
  75. GRB990123, early optical counterpart detection
  76. GRB990123 Optical Observation
  77. Possible identification of SN1999E with GRB980910
  78. Optical Observations of GRB 981220
  79. GRB 981226: radio variable
  80. GRB981220
  81. GRB981220, Correction to GCN 179
  82. GRB 981220 Optical observations
  83. GRB 981226 Optical Observations
  84. GRB 981220 and GRB 981226, optical observations
  85. GRB981226 Optical Observations
  86. GRB981226 BeppoSAX follow up
  87. GRB 981226
  88. GRB 981226 optical observations
  89. GRB981220 B, R and I band observations
  90. Optical Observations of GRB981226
  91. GRB 981220:Optical Observations
  92. GRB 981226 optical observations
  93. GRB 981220
  94. GRB 981220, radio observations
  95. GRB981220 I-band Observations
  96. GRB 981220
  97. GRB 980326/Host Galaxy
  98. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  99. BeppoSAX NFI Observation of GRB980425
  100. GRB980329 R,I flux calibration and R,I,K upper limits

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