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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"

35433 results found.

  1. GRB981220 VLBA observations
  2. GRB990321 REFINED IPN ANNULUS
  3. GRB990323 PRECISE IPN POSITION
  4. GRB990321 IPN TRIANGULATION
  5. GRB 990316 Optical Observations
  6. GRB 990316, Radio observations
  7. GRB 990316, Optical observations
  8. GRB990316, Optical observations
  9. GRB 990316 optical observations
  10. GRB990316: simultaneous optical observation
  11. ASM/IPN error box for GRB 990308 (BATSE #7457)
  12. GRB990308 not a new SGR
  13. GRB 990308a and GRB 990308b
  14. GRB990308 (Trig. 7457), optical observations
  15. GRB981220, IPN localization
  16. GRB 981220, radio observations
  17. GRB 990123, Field Photometry
  18. GRB 990217 Optical Observations
  19. GRB 990217, radio observations
  20. Optical Observations of GRB990217
  21. GRB990123: Caltech STIS Photometry and Images
  22. GRB990123 observations
  23. GRB990123, Optical Observation
  24. GRB 990123: Discovery of the Probable Host Galaxy
  25. GRB 990123: Reduced HST Images
  26. For Immediate Posting to GCN - HST Data GRB 990123 Available
  27. GRB19990123 observations
  28. GRB 990123: BVRI standards in the field
  29. GRB 990123: Updated Keck Spectroscopy Results
  30. GRB981220, field photometry
  31. GRB 990123 NOT Spectrum Update
  32. GRB990123, Optical observation
  33. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  34. GRB 990123: Publicly available reduced HST images
  35. GRB990123, Upcoming HST Service Observations
  36. GRB 990123: New Constraints on Possible Foreground Galaxies
  37. GRB990123 Optical Observations
  38. GRB990123, Probability of gravitational lensing
  39. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  40. GRB 990123: Continued Radio Observations
  41. GRB990123, Preliminary Lens Search Results
  42. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  43. On the Lensing Interpretation of GRB 990123
  44. Search for Potential Images of GRB 990123
  45. Search for Potential Images of GRB 990123
  46. GRB990123, Optical BVRI Observations
  47. GRB 990123: near-infrared observations.
  48. GRB990123, OSSE observations
  49. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  50. "GRB 990123: New BV Observations"
  51. GRB 990123 Optical Follow-Up
  52. GRB 990123; Addendum to GCN 223
  53. GRB 990123: BATSE Observations
  54. GRB 990123 Keck Spectrum update
  55. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  56. GRB990123 Optical Observations
  57. GRB 990123 Spectroscopic Redshifts
  58. GRB 990123: New Optical Observations, Decay Measure
  59. GRB 990123 Optical Follow-Up
  60. GRB 990123: Possible Gravitationally Lensed Burst?
  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 observation
  66. GRB 990123: Optical Decay Slope
  67. GRB 990123 r-band photometry
  68. GRB 990123 Optical Follow-up
  69. GRB990123, early optical counterpart detection
  70. GRB990123 Optical Observation
  71. GRB 990123: Bright New Source, Possible Optical Transient
  72. GRB 990123, Radio observations
  73. SN 1999E & GRB 980919
  74. Possible identification of SN1999E with GRB980910
  75. Optical Observations of GRB 981220
  76. GRB 981226: radio variable
  77. GRB981220
  78. GRB981220, Optical Observations
  79. GRB 981220 Optical observations
  80. GRB 981226 Optical Observations
  81. GRB 980613: Spectroscopy of the host galaxy
  82. GRB981226, sub-millimeter observations
  83. GRB981220, sub-millimeter observations
  84. GRB 981220 and GRB 981226, optical observations
  85. GRB 981226 radio observations
  86. GRB 981226
  87. GRB 981226 optical observations
  88. radio observations of GRB 981226
  89. GRB981220 B, R and I band observations
  90. GRB 981220:Optical Observations
  91. GRB 981220 optical R and I observations
  92. GRB981226, BeppoSAX Christmas GRB
  93. GRB 981226 - Infrared Observations
  94. GRB 981226 optical observations
  95. GRB 981220
  96. GRB 981220, radio observations
  97. GRB981226 Optical Observation
  98. GRB 981220, radio observations
  99. GRB 981220: BeppoSAX/GRBM results
  100. GRB981220 I-band Observations

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