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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"

32506 results found.

  1. GRB 990506: Limits on the possible optical transient
  2. GRB 990506, armchair astronomy
  3. GRB 990506, optical observations from +1 to +3 hours
  4. GRB 990506, optical observations
  5. GRB990506 observation plan
  6. New IPN/RXTE error box for GRB990506
  7. IPN localization for GRB990506
  8. GRB 970228: Redshift and properties of the host galaxy
  9. GRB981220 VLBA observations
  10. GRB990321 REFINED IPN ANNULUS
  11. GRB990323 PRECISE IPN POSITION
  12. GRB 990316 Optical Observations
  13. GRB 990316, Radio observations
  14. GRB 990316, Optical observations
  15. GRB990316, Optical observations
  16. GRB 990316 optical observations
  17. GRB990316: simultaneous optical observation
  18. GRB990308 not a new SGR
  19. GRB 990308a and GRB 990308b
  20. GRB990308 (Trig. 7457), optical observations
  21. GRB981220, IPN localization
  22. GRB 981220, radio observations
  23. GRB 990123, Field Photometry
  24. GRB 990217, radio observations
  25. BATSE Resumes Normal Operations
  26. BATSE Flight Anomaly
  27. GRB990123: Caltech STIS Photometry and Images
  28. GRB990123 observations
  29. GRB990123, Optical Observation
  30. GRB 990123: Discovery of the Probable Host Galaxy
  31. GRB 990123: Reduced HST Images
  32. For Immediate Posting to GCN - HST Data GRB 990123 Available
  33. GRB19990123 observations
  34. GRB 990123: Updated Keck Spectroscopy Results
  35. GRB 990123 NOT Spectrum Update
  36. GRB990123, Optical observation
  37. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  38. GRB 990123: Publicly available reduced HST images
  39. GRB 990123: New Constraints on Possible Foreground Galaxies
  40. GRB990123 Optical Observations
  41. GRB990123, Probability of gravitational lensing
  42. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  43. GRB 990123: Continued Radio Observations
  44. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  45. On the Lensing Interpretation of GRB 990123
  46. Search for Potential Images of GRB 990123
  47. Search for Potential Images of GRB 990123
  48. GRB990123, Optical BVRI Observations
  49. GRB 990123: near-infrared observations.
  50. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  51. GRB990123: NIR Observation
  52. "GRB 990123: New BV Observations"
  53. GRB 990123 Optical Follow-Up
  54. GRB 990123; Addendum to GCN 223
  55. GRB 990123: BATSE Observations
  56. GRB 990123 Keck Spectrum update
  57. GRB990123 IPN annulus
  58. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  59. GRB990123 Optical Observations
  60. GRB 990123 Spectroscopic Redshifts
  61. GRB 990123: New Optical Observations, Decay Measure
  62. GRB 990123 Optical Follow-Up
  63. GRB 990123: Possible Gravitationally Lensed Burst?
  64. GRB990123, optical observation
  65. GRB 990123 optical observations
  66. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  67. GRB 990123 radio observations
  68. GRB 990123, new radio source
  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. GRB 990123: Bright New Source, Possible Optical Transient
  76. GRB 990123, Radio observations
  77. SN 1999E & GRB 980919
  78. Optical Observations of GRB 981220
  79. GRB 981226: radio variable
  80. GRB981220
  81. GRB981220, Correction to GCN 179
  82. GRB981220, Optical Observations
  83. GRB 981220 Optical observations
  84. GRB 981226 Optical Observations
  85. GRB 980613: Spectroscopy of the host galaxy
  86. GRB981226, sub-millimeter observations
  87. GRB981220, sub-millimeter observations
  88. GRB 981220 and GRB 981226, optical observations
  89. GRB981226 Optical Observations
  90. GRB 981226 radio observations
  91. GRB 981226
  92. radio observations of GRB 981226
  93. GRB981220 B, R and I band observations
  94. Optical Observations of GRB981226
  95. GRB 981220:Optical Observations
  96. GRB 981220 optical R and I observations
  97. GRB981226, BeppoSAX Christmas GRB
  98. GRB 981226 - Infrared Observations
  99. GRB 981220
  100. GRB 981220, radio observations

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