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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. GRB990217, WFC position
  2. GRB990123, Optical Observation
  3. GRB 990123: Discovery of the Probable Host Galaxy
  4. GRB 990123: Reduced HST Images
  5. For Immediate Posting to GCN - HST Data GRB 990123 Available
  6. GRB19990123 observations
  7. GRB 990123: BVRI standards in the field
  8. GRB 990123: Updated Keck Spectroscopy Results
  9. GRB981220, field photometry
  10. GRB 990123 NOT Spectrum Update
  11. GRB990123, Optical observation
  12. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  13. GRB 990123: Publicly available reduced HST images
  14. GRB990123, Upcoming HST Service Observations
  15. GRB990123, 15-GHz limits
  16. GRB 990123: New Constraints on Possible Foreground Galaxies
  17. GRB990123 Optical Observations
  18. GRB990123, Probability of gravitational lensing
  19. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  20. GRB 990123: Continued Radio Observations
  21. GRB990123, Preliminary Lens Search Results
  22. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  23. On the Lensing Interpretation of GRB 990123
  24. Search for Potential Images of GRB 990123
  25. Search for Potential Images of GRB 990123
  26. GRB990123, Optical BVRI Observations
  27. GRB 990123: near-infrared observations.
  28. GRB990123, OSSE observations
  29. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  30. GRB990123: NIR Observation
  31. GRB990123, ASCA X-ray observation of afterglow
  32. "GRB 990123: New BV Observations"
  33. GRB 990123 Optical Follow-Up
  34. GRB 990123; Addendum to GCN 223
  35. GRB 990123: BATSE Observations
  36. GRB 990123 Keck Spectrum update
  37. GRB990123 IPN annulus
  38. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  39. GRB990123 Optical Observations
  40. GRB 990123 Spectroscopic Redshifts
  41. GRB 990123: New Optical Observations, Decay Measure
  42. GRB 990123 Optical Follow-Up
  43. GRB 990123: Possible Gravitationally Lensed Burst?
  44. GRB990123, optical observation
  45. GRB 990123 optical observations
  46. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  47. GRB 990123 radio observations
  48. GRB 990123, new radio source
  49. GRB990123 optical observations
  50. GRB990123, Optical observation
  51. GRB 990123: Optical Decay Slope
  52. GRB 990123 r-band photometry
  53. GRB 990123 Optical Follow-up
  54. GRB990123, early optical counterpart detection
  55. GRB990123 Optical Observation
  56. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  57. GRB990123, refined SAX-WFC position
  58. GRB 990123: Bright New Source, Possible Optical Transient
  59. GRB 990123, Radio observations
  60. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  61. SN 1999E & GRB 980919
  62. Possible identification of SN1999E with GRB980910
  63. Optical Observations of GRB 981220
  64. GRB 981226: radio variable
  65. GRB981220
  66. GRB981220, Correction to GCN 179
  67. GRB981220, Optical Observations
  68. GRB 981220 Optical observations
  69. GRB 981226 Optical Observations
  70. GRB 980613: Spectroscopy of the host galaxy
  71. GRB981226, sub-millimeter observations
  72. GRB981220, sub-millimeter observations
  73. GRB 981220 and GRB 981226, optical observations
  74. GRB981226 Optical Observations
  75. GRB981226 BeppoSAX follow up
  76. GRB 981226 radio observations
  77. GRB 981226
  78. GRB 981226 optical observations
  79. radio observations of GRB 981226
  80. GRB981220 B, R and I band observations
  81. GRB981226, BeppoSAX-NFI follow-up
  82. Optical Observations of GRB981226
  83. GRB 981220:Optical Observations
  84. GRB 981220 optical R and I observations
  85. GRB981226, BeppoSAX Christmas GRB
  86. GRB 981226 - Infrared Observations
  87. GRB 981226 optical observations
  88. GRB 981220
  89. GRB 981220, radio observations
  90. GRB981226 Optical Observation
  91. GRB 981220, radio observations
  92. GRB 981220: BeppoSAX/GRBM results
  93. GRB981220 I-band Observations
  94. GRB981220 Optical Observations
  95. GRB 981220
  96. GRB 981220 Optical Observations
  97. GRB 981220, optical observations
  98. GRB 980326/Host Galaxy
  99. GRB981220 IPN error box
  100. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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