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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"

32498 results found.

  1. GRB981220 VLBA observations
  2. GRB990321 REFINED IPN ANNULUS
  3. GRB990323 PRECISE IPN POSITION
  4. GRB 990316 Optical Observations
  5. GRB 990316, Radio observations
  6. GRB 990316, Optical observations
  7. GRB990316, Optical observations
  8. GRB 990316 optical observations
  9. GRB990316: simultaneous optical observation
  10. GRB990308 not a new SGR
  11. GRB 990308a and GRB 990308b
  12. GRB990308 (Trig. 7457), optical observations
  13. GRB981220, IPN localization
  14. GRB 981220, radio observations
  15. GRB 990123, Field Photometry
  16. GRB 990217, radio observations
  17. BATSE Resumes Normal Operations
  18. BATSE Flight Anomaly
  19. GRB990123: Caltech STIS Photometry and Images
  20. GRB990123 observations
  21. GRB990123, Optical Observation
  22. GRB 990123: Discovery of the Probable Host Galaxy
  23. GRB 990123: Reduced HST Images
  24. For Immediate Posting to GCN - HST Data GRB 990123 Available
  25. GRB19990123 observations
  26. GRB 990123: Updated Keck Spectroscopy Results
  27. GRB 990123 NOT Spectrum Update
  28. GRB990123, Optical observation
  29. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  30. GRB 990123: Publicly available reduced HST images
  31. GRB 990123: New Constraints on Possible Foreground Galaxies
  32. GRB990123 Optical Observations
  33. GRB990123, Probability of gravitational lensing
  34. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  35. GRB 990123: Continued Radio Observations
  36. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  37. On the Lensing Interpretation of GRB 990123
  38. Search for Potential Images of GRB 990123
  39. Search for Potential Images of GRB 990123
  40. GRB990123, Optical BVRI Observations
  41. GRB 990123: near-infrared observations.
  42. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  43. GRB990123: NIR Observation
  44. "GRB 990123: New BV Observations"
  45. GRB 990123 Optical Follow-Up
  46. GRB 990123; Addendum to GCN 223
  47. GRB 990123: BATSE Observations
  48. GRB 990123 Keck Spectrum update
  49. GRB990123 IPN annulus
  50. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  51. GRB990123 Optical Observations
  52. GRB 990123 Spectroscopic Redshifts
  53. GRB 990123: New Optical Observations, Decay Measure
  54. GRB 990123 Optical Follow-Up
  55. GRB 990123: Possible Gravitationally Lensed Burst?
  56. GRB990123, optical observation
  57. GRB 990123 optical observations
  58. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  59. GRB 990123 radio observations
  60. GRB 990123, new radio source
  61. GRB990123, Optical observation
  62. GRB 990123: Optical Decay Slope
  63. GRB 990123 r-band photometry
  64. GRB 990123 Optical Follow-up
  65. GRB990123, early optical counterpart detection
  66. GRB990123 Optical Observation
  67. GRB 990123: Bright New Source, Possible Optical Transient
  68. GRB 990123, Radio observations
  69. SN 1999E & GRB 980919
  70. Optical Observations of GRB 981220
  71. GRB 981226: radio variable
  72. GRB981220
  73. GRB981220, Correction to GCN 179
  74. GRB981220, Optical Observations
  75. GRB 981220 Optical observations
  76. GRB 981226 Optical Observations
  77. GRB 980613: Spectroscopy of the host galaxy
  78. GRB981226, sub-millimeter observations
  79. GRB981220, sub-millimeter observations
  80. GRB 981220 and GRB 981226, optical observations
  81. GRB981226 Optical Observations
  82. GRB 981226 radio observations
  83. GRB 981226
  84. radio observations of GRB 981226
  85. GRB981220 B, R and I band observations
  86. Optical Observations of GRB981226
  87. GRB 981220:Optical Observations
  88. GRB 981220 optical R and I observations
  89. GRB981226, BeppoSAX Christmas GRB
  90. GRB 981226 - Infrared Observations
  91. GRB 981220
  92. GRB 981220, radio observations
  93. GRB 981220, radio observations
  94. GRB 981220: BeppoSAX/GRBM results
  95. GRB981220 I-band Observations
  96. GRB 981220
  97. GRB 981220 Optical Observations
  98. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  99. BeppoSAX NFI Observation of GRB980425
  100. GRB980425 Optical Follow-up

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