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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"

32495 results found.

  1. GRB 990316 Optical Observations
  2. GRB 990316, Radio observations
  3. GRB 990316, Optical observations
  4. GRB990316, Optical observations
  5. GRB 990316 optical observations
  6. GRB990316: simultaneous optical observation
  7. GRB990308 not a new SGR
  8. GRB 990308a and GRB 990308b
  9. GRB990308 (Trig. 7457), optical observations
  10. GRB981220, IPN localization
  11. GRB 981220, radio observations
  12. GRB 990123, Field Photometry
  13. GRB 990217, radio observations
  14. BATSE Resumes Normal Operations
  15. BATSE Flight Anomaly
  16. GRB990123: Caltech STIS Photometry and Images
  17. GRB990123 observations
  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: Updated Keck Spectroscopy Results
  24. GRB 990123 NOT Spectrum Update
  25. GRB990123, Optical observation
  26. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  27. GRB 990123: Publicly available reduced HST images
  28. GRB 990123: New Constraints on Possible Foreground Galaxies
  29. GRB990123 Optical Observations
  30. GRB990123, Probability of gravitational lensing
  31. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  32. GRB 990123: Continued Radio Observations
  33. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  34. On the Lensing Interpretation of GRB 990123
  35. Search for Potential Images of GRB 990123
  36. Search for Potential Images of GRB 990123
  37. GRB990123, Optical BVRI Observations
  38. GRB 990123: near-infrared observations.
  39. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  40. GRB990123: NIR Observation
  41. "GRB 990123: New BV Observations"
  42. GRB 990123 Optical Follow-Up
  43. GRB 990123; Addendum to GCN 223
  44. GRB 990123: BATSE Observations
  45. GRB 990123 Keck Spectrum update
  46. GRB990123 IPN annulus
  47. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  48. GRB990123 Optical Observations
  49. GRB 990123 Spectroscopic Redshifts
  50. GRB 990123: New Optical Observations, Decay Measure
  51. GRB 990123 Optical Follow-Up
  52. GRB 990123: Possible Gravitationally Lensed Burst?
  53. GRB990123, optical observation
  54. GRB 990123 optical observations
  55. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  56. GRB 990123 radio observations
  57. GRB 990123, new radio source
  58. GRB990123, Optical observation
  59. GRB 990123: Optical Decay Slope
  60. GRB 990123 r-band photometry
  61. GRB 990123 Optical Follow-up
  62. GRB990123, early optical counterpart detection
  63. GRB990123 Optical Observation
  64. GRB 990123: Bright New Source, Possible Optical Transient
  65. GRB 990123, Radio observations
  66. SN 1999E & GRB 980919
  67. Optical Observations of GRB 981220
  68. GRB 981226: radio variable
  69. GRB981220
  70. GRB981220, Correction to GCN 179
  71. GRB981220, Optical Observations
  72. GRB 981220 Optical observations
  73. GRB 981226 Optical Observations
  74. GRB 980613: Spectroscopy of the host galaxy
  75. GRB981226, sub-millimeter observations
  76. GRB981220, sub-millimeter observations
  77. GRB 981220 and GRB 981226, optical observations
  78. GRB981226 Optical Observations
  79. GRB 981226 radio observations
  80. GRB 981226
  81. radio observations of GRB 981226
  82. GRB981220 B, R and I band observations
  83. Optical Observations of GRB981226
  84. GRB 981220:Optical Observations
  85. GRB 981220 optical R and I observations
  86. GRB981226, BeppoSAX Christmas GRB
  87. GRB 981226 - Infrared Observations
  88. GRB 981220
  89. GRB 981220, radio observations
  90. GRB 981220, radio observations
  91. GRB 981220: BeppoSAX/GRBM results
  92. GRB981220 I-band Observations
  93. GRB 981220
  94. GRB 981220 Optical Observations
  95. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  96. BeppoSAX NFI Observation of GRB980425
  97. GRB980425 Optical Follow-up
  98. GRB980425: X-ray revised positions
  99. GRB980703 Very Long Baseline Interferometry
  100. GRB970508 optical observations

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