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

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