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

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