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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. For Immediate Posting to GCN - HST Data GRB 990123 Available
  2. GRB19990123 observations
  3. GRB 990123: BVRI standards in the field
  4. GRB 990123: Updated Keck Spectroscopy Results
  5. GRB981220, field photometry
  6. GRB 990123 NOT Spectrum Update
  7. GRB990123, Optical observation
  8. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  9. GRB 990123: Publicly available reduced HST images
  10. GRB990123, Upcoming HST Service Observations
  11. GRB990123, 15-GHz limits
  12. GRB 990123: New Constraints on Possible Foreground Galaxies
  13. GRB990123 Optical Observations
  14. GRB990123, Probability of gravitational lensing
  15. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  16. GRB 990123: Continued Radio Observations
  17. GRB990123, Preliminary Lens Search Results
  18. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  19. On the Lensing Interpretation of GRB 990123
  20. Search for Potential Images of GRB 990123
  21. Search for Potential Images of GRB 990123
  22. GRB990123, Optical BVRI Observations
  23. GRB 990123: near-infrared observations.
  24. GRB990123, OSSE observations
  25. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  26. GRB990123: NIR Observation
  27. GRB990123, ASCA X-ray observation of afterglow
  28. "GRB 990123: New BV Observations"
  29. GRB 990123 Optical Follow-Up
  30. GRB 990123; Addendum to GCN 223
  31. GRB 990123: BATSE Observations
  32. GRB 990123 Keck Spectrum update
  33. GRB990123 IPN annulus
  34. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  35. GRB990123 Optical Observations
  36. GRB 990123 Spectroscopic Redshifts
  37. GRB 990123: New Optical Observations, Decay Measure
  38. GRB 990123 Optical Follow-Up
  39. GRB 990123: Possible Gravitationally Lensed Burst?
  40. GRB990123, optical observation
  41. GRB 990123 optical observations
  42. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  43. GRB 990123 radio observations
  44. GRB 990123, new radio source
  45. GRB990123 optical observations
  46. GRB990123, Optical observation
  47. GRB 990123: Optical Decay Slope
  48. GRB 990123 r-band photometry
  49. GRB 990123 Optical Follow-up
  50. GRB990123, early optical counterpart detection
  51. GRB990123 Optical Observation
  52. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  53. GRB990123, refined SAX-WFC position
  54. GRB 990123: Bright New Source, Possible Optical Transient
  55. GRB 990123, Radio observations
  56. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  57. SN 1999E & GRB 980919
  58. Possible identification of SN1999E with GRB980910
  59. Optical Observations of GRB 981220
  60. GRB 981226: radio variable
  61. GRB981220
  62. GRB981220, Correction to GCN 179
  63. GRB981220, Optical Observations
  64. GRB 981220 Optical observations
  65. GRB 981226 Optical Observations
  66. GRB 980613: Spectroscopy of the host galaxy
  67. GRB981226, sub-millimeter observations
  68. GRB981220, sub-millimeter observations
  69. GRB 981220 and GRB 981226, optical observations
  70. GRB981226 Optical Observations
  71. GRB981226 BeppoSAX follow up
  72. GRB 981226 radio observations
  73. GRB 981226
  74. GRB 981226 optical observations
  75. radio observations of GRB 981226
  76. GRB981220 B, R and I band observations
  77. GRB981226, BeppoSAX-NFI follow-up
  78. Optical Observations of GRB981226
  79. GRB 981220:Optical Observations
  80. GRB 981220 optical R and I observations
  81. GRB981226, BeppoSAX Christmas GRB
  82. GRB 981226 - Infrared Observations
  83. GRB 981226 optical observations
  84. GRB 981220
  85. GRB 981220, radio observations
  86. GRB981226 Optical Observation
  87. GRB 981220, radio observations
  88. GRB 981220: BeppoSAX/GRBM results
  89. GRB981220 I-band Observations
  90. GRB981220 Optical Observations
  91. GRB 981220
  92. GRB 981220 Optical Observations
  93. GRB 981220, optical observations
  94. GRB 980326/Host Galaxy
  95. GRB981220 IPN error box
  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. GRB980425: X-ray revised positions

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