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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"

35332 results found.

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

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