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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. GRB990323 PRECISE IPN POSITION
  2. GRB990321 IPN TRIANGULATION
  3. GRB 990316 Optical Observations
  4. GRB 990316, Radio observations
  5. GRB 990316, Optical observations
  6. GRB990316, Optical observations
  7. GRB 990316 optical observations
  8. GRB990316: simultaneous optical observation
  9. GRB990316 - Optical null results
  10. ASM/IPN error box for GRB 990308 (BATSE #7457)
  11. GRB990308 not a new SGR
  12. GRB 990308a and GRB 990308b
  13. GRB990308 (Trig. 7457), optical observations
  14. GRB990308, Possible new SGR~0209+70
  15. GRB981220, IPN localization
  16. GRB 981220, radio observations
  17. GRB 990123, Field Photometry
  18. GRB 990217 Optical Observations
  19. GRB 990217, radio observations
  20. BATSE Resumes Normal Operations
  21. BATSE Flight Anomaly
  22. GRB990217: BeppoSAX/GRBM data
  23. Optical Observations of GRB990217
  24. GRB990123: Caltech STIS Photometry and Images
  25. GRB990123 observations
  26. GRB990217 Optical observation
  27. GRB990217, WFC position
  28. GRB990123, Optical Observation
  29. GRB 990123: Discovery of the Probable Host Galaxy
  30. GRB 990123: Reduced HST Images
  31. For Immediate Posting to GCN - HST Data GRB 990123 Available
  32. GRB19990123 observations
  33. GRB 990123: BVRI standards in the field
  34. GRB 990123: Updated Keck Spectroscopy Results
  35. GRB981220, field photometry
  36. GRB 990123 NOT Spectrum Update
  37. GRB990123, Optical observation
  38. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  39. GRB 990123: Publicly available reduced HST images
  40. GRB990123, Upcoming HST Service Observations
  41. GRB990123, 15-GHz limits
  42. GRB 990123: New Constraints on Possible Foreground Galaxies
  43. GRB990123 Optical Observations
  44. GRB990123, Probability of gravitational lensing
  45. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  46. GRB 990123: Continued Radio Observations
  47. GRB990123, Preliminary Lens Search Results
  48. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  49. On the Lensing Interpretation of GRB 990123
  50. Search for Potential Images of GRB 990123
  51. Search for Potential Images of GRB 990123
  52. GRB990123, Optical BVRI Observations
  53. GRB 990123: near-infrared observations.
  54. GRB990123, OSSE observations
  55. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  56. GRB990123: NIR Observation
  57. GRB990123, ASCA X-ray observation of afterglow
  58. "GRB 990123: New BV Observations"
  59. GRB 990123 Optical Follow-Up
  60. GRB 990123; Addendum to GCN 223
  61. GRB 990123: BATSE Observations
  62. GRB 990123 Keck Spectrum update
  63. GRB990123 IPN annulus
  64. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  65. GRB990123 Optical Observations
  66. GRB 990123 Spectroscopic Redshifts
  67. GRB 990123: New Optical Observations, Decay Measure
  68. GRB 990123 Optical Follow-Up
  69. GRB 990123: Possible Gravitationally Lensed Burst?
  70. GRB990123, optical observation
  71. GRB 990123 optical observations
  72. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  73. GRB 990123 radio observations
  74. GRB 990123, new radio source
  75. GRB990123 optical observations
  76. GRB990123, Optical observation
  77. GRB 990123: Optical Decay Slope
  78. GRB 990123 r-band photometry
  79. GRB 990123 Optical Follow-up
  80. GRB990123, early optical counterpart detection
  81. GRB990123 Optical Observation
  82. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  83. GRB990123, refined SAX-WFC position
  84. GRB 990123: Bright New Source, Possible Optical Transient
  85. GRB 990123, Radio observations
  86. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  87. SN 1999E & GRB 980919
  88. Possible identification of SN1999E with GRB980910
  89. Optical Observations of GRB 981220
  90. GRB 981226: radio variable
  91. GRB981220
  92. GRB981220, Correction to GCN 179
  93. GRB981220, Optical Observations
  94. GRB 981220 Optical observations
  95. GRB 981226 Optical Observations
  96. GRB 980613: Spectroscopy of the host galaxy
  97. GRB981226, sub-millimeter observations
  98. GRB981220, sub-millimeter observations
  99. GRB 981220 and GRB 981226, optical observations
  100. GRB981226 Optical Observations

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