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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').
  1. GRB 990217 Optical Observations
  2. GRB 990217, radio observations
  3. BATSE Resumes Normal Operations
  4. BATSE Flight Anomaly
  5. GRB990217: BeppoSAX/GRBM data
  6. Optical Observations of GRB990217
  7. GRB990123: Caltech STIS Photometry and Images
  8. GRB990123 observations
  9. GRB990217 Optical observation
  10. GRB990217, WFC position
  11. GRB990123, Optical Observation
  12. GRB 990123: Discovery of the Probable Host Galaxy
  13. GRB 990123: Reduced HST Images
  14. For Immediate Posting to GCN - HST Data GRB 990123 Available
  15. GRB19990123 observations
  16. GRB 990123: BVRI standards in the field
  17. GRB 990123: Updated Keck Spectroscopy Results
  18. GRB981220, field photometry
  19. GRB 990123 NOT Spectrum Update
  20. GRB990123, Optical observation
  21. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  22. GRB 990123: Publicly available reduced HST images
  23. GRB990123, Upcoming HST Service Observations
  24. GRB990123, 15-GHz limits
  25. GRB 990123: New Constraints on Possible Foreground Galaxies
  26. GRB990123 Optical Observations
  27. GRB990123, Probability of gravitational lensing
  28. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  29. GRB 990123: Continued Radio Observations
  30. GRB990123, Preliminary Lens Search Results
  31. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  32. On the Lensing Interpretation of GRB 990123
  33. Search for Potential Images of GRB 990123
  34. Search for Potential Images of GRB 990123
  35. GRB990123, Optical BVRI Observations
  36. GRB 990123: near-infrared observations.
  37. GRB990123, OSSE observations
  38. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  39. GRB990123: NIR Observation
  40. GRB990123, ASCA X-ray observation of afterglow
  41. "GRB 990123: New BV Observations"
  42. GRB 990123 Optical Follow-Up
  43. GRB 990123; Addendum to GCN 223
  44. GRB 990123: BATSE Observations
  45. GRB 990123 Keck Spectrum update
  46. GRB990123 IPN annulus
  47. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  48. GRB990123 Optical Observations
  49. GRB 990123 Spectroscopic Redshifts
  50. GRB 990123: New Optical Observations, Decay Measure
  51. GRB 990123 Optical Follow-Up
  52. GRB 990123: Possible Gravitationally Lensed Burst?
  53. GRB990123, optical observation
  54. GRB 990123 optical observations
  55. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  56. GRB 990123 radio observations
  57. GRB 990123, new radio source
  58. GRB990123 optical observations
  59. GRB990123, Optical observation
  60. GRB 990123: Optical Decay Slope
  61. GRB 990123 r-band photometry
  62. GRB 990123 Optical Follow-up
  63. GRB990123, early optical counterpart detection
  64. GRB990123 Optical Observation
  65. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  66. GRB990123, refined SAX-WFC position
  67. GRB 990123: Bright New Source, Possible Optical Transient
  68. GRB 990123, Radio observations
  69. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  70. SN 1999E & GRB 980919
  71. Possible identification of SN1999E with GRB980910
  72. Optical Observations of GRB 981220
  73. GRB 981226: radio variable
  74. GRB981220
  75. GRB981220, Correction to GCN 179
  76. GRB981220, Optical Observations
  77. GRB 981220 Optical observations
  78. GRB 981226 Optical Observations
  79. GRB 980613: Spectroscopy of the host galaxy
  80. GRB981226, sub-millimeter observations
  81. GRB981220, sub-millimeter observations
  82. GRB 981220 and GRB 981226, optical observations
  83. GRB981226 Optical Observations
  84. GRB981226 BeppoSAX follow up
  85. GRB 981226 radio observations
  86. GRB 981226
  87. GRB 981226 optical observations
  88. radio observations of GRB 981226
  89. GRB981220 B, R and I band observations
  90. GRB981226, BeppoSAX-NFI follow-up
  91. Optical Observations of GRB981226
  92. GRB 981220:Optical Observations
  93. GRB 981220 optical R and I observations
  94. GRB981226, BeppoSAX Christmas GRB
  95. GRB 981226 - Infrared Observations
  96. GRB 981226 optical observations
  97. GRB 981220
  98. GRB 981220, radio observations
  99. GRB981226 Optical Observation
  100. GRB 981220, radio observations

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