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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. GRB 970228: Redshift and properties of the host galaxy
  2. IPN localization of GRB990427
  3. GRB981220 VLBA observations
  4. GRB980425 Optical observations of exponential decline at late time
  5. GRB990321 REFINED IPN ANNULUS
  6. GRB990323 PRECISE IPN POSITION
  7. GRB990321 IPN TRIANGULATION
  8. GRB 990316 Optical Observations
  9. GRB 990316, Radio observations
  10. GRB 990316, Optical observations
  11. GRB990316, Optical observations
  12. GRB 990316 optical observations
  13. GRB990316: simultaneous optical observation
  14. GRB990316 - Optical null results
  15. ASM/IPN error box for GRB 990308 (BATSE #7457)
  16. GRB990308 not a new SGR
  17. GRB 990308a and GRB 990308b
  18. GRB990308 (Trig. 7457), optical observations
  19. GRB990308, Possible new SGR~0209+70
  20. GRB981220, IPN localization
  21. GRB 981220, radio observations
  22. GRB 990123, Field Photometry
  23. GRB 990217 Optical Observations
  24. GRB 990217, radio observations
  25. BATSE Resumes Normal Operations
  26. BATSE Flight Anomaly
  27. GRB990217: BeppoSAX/GRBM data
  28. Optical Observations of GRB990217
  29. GRB990123: Caltech STIS Photometry and Images
  30. GRB990123 observations
  31. GRB990217 Optical observation
  32. GRB990217, WFC position
  33. GRB990123, Optical Observation
  34. GRB 990123: Discovery of the Probable Host Galaxy
  35. GRB 990123: Reduced HST Images
  36. For Immediate Posting to GCN - HST Data GRB 990123 Available
  37. GRB19990123 observations
  38. GRB 990123: BVRI standards in the field
  39. GRB 990123: Updated Keck Spectroscopy Results
  40. GRB981220, field photometry
  41. GRB 990123 NOT Spectrum Update
  42. GRB990123, Optical observation
  43. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  44. GRB 990123: Publicly available reduced HST images
  45. GRB990123, Upcoming HST Service Observations
  46. GRB990123, 15-GHz limits
  47. GRB 990123: New Constraints on Possible Foreground Galaxies
  48. GRB990123 Optical Observations
  49. GRB990123, Probability of gravitational lensing
  50. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  51. GRB 990123: Continued Radio Observations
  52. GRB990123, Preliminary Lens Search Results
  53. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  54. On the Lensing Interpretation of GRB 990123
  55. Search for Potential Images of GRB 990123
  56. Search for Potential Images of GRB 990123
  57. GRB990123, Optical BVRI Observations
  58. GRB 990123: near-infrared observations.
  59. GRB990123, OSSE observations
  60. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  61. GRB990123: NIR Observation
  62. GRB990123, ASCA X-ray observation of afterglow
  63. "GRB 990123: New BV Observations"
  64. GRB 990123 Optical Follow-Up
  65. GRB 990123; Addendum to GCN 223
  66. GRB 990123: BATSE Observations
  67. GRB 990123 Keck Spectrum update
  68. GRB990123 IPN annulus
  69. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  70. GRB990123 Optical Observations
  71. GRB 990123 Spectroscopic Redshifts
  72. GRB 990123: New Optical Observations, Decay Measure
  73. GRB 990123 Optical Follow-Up
  74. GRB 990123: Possible Gravitationally Lensed Burst?
  75. GRB990123, optical observation
  76. GRB 990123 optical observations
  77. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  78. GRB 990123 radio observations
  79. GRB 990123, new radio source
  80. GRB990123 optical observations
  81. GRB990123, Optical observation
  82. GRB 990123: Optical Decay Slope
  83. GRB 990123 r-band photometry
  84. GRB 990123 Optical Follow-up
  85. GRB990123, early optical counterpart detection
  86. GRB990123 Optical Observation
  87. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  88. GRB990123, refined SAX-WFC position
  89. GRB 990123: Bright New Source, Possible Optical Transient
  90. GRB 990123, Radio observations
  91. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  92. SN 1999E & GRB 980919
  93. Possible identification of SN1999E with GRB980910
  94. Optical Observations of GRB 981220
  95. GRB 981226: radio variable
  96. GRB981220
  97. GRB981220, Correction to GCN 179
  98. GRB981220, Optical Observations
  99. GRB 981220 Optical observations
  100. GRB 981226 Optical Observations

Advanced

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