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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"

35324 results found.

  1. GRB990316: simultaneous optical observation
  2. ASM/IPN error box for GRB 990308 (BATSE #7457)
  3. GRB990308 not a new SGR
  4. GRB 990308a and GRB 990308b
  5. GRB990308 (Trig. 7457), optical observations
  6. GRB981220, IPN localization
  7. GRB 981220, radio observations
  8. GRB 990123, Field Photometry
  9. GRB 990217 Optical Observations
  10. GRB 990217, radio observations
  11. Optical Observations of GRB990217
  12. GRB990123: Caltech STIS Photometry and Images
  13. GRB990123 observations
  14. GRB990123, Optical Observation
  15. GRB 990123: Discovery of the Probable Host Galaxy
  16. GRB 990123: Reduced HST Images
  17. For Immediate Posting to GCN - HST Data GRB 990123 Available
  18. GRB19990123 observations
  19. GRB 990123: BVRI standards in the field
  20. GRB 990123: Updated Keck Spectroscopy Results
  21. GRB981220, field photometry
  22. GRB 990123 NOT Spectrum Update
  23. GRB990123, Optical observation
  24. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  25. GRB 990123: Publicly available reduced HST images
  26. GRB990123, Upcoming HST Service Observations
  27. GRB 990123: New Constraints on Possible Foreground Galaxies
  28. GRB990123 Optical Observations
  29. GRB990123, Probability of gravitational lensing
  30. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  31. GRB 990123: Continued Radio Observations
  32. GRB990123, Preliminary Lens Search Results
  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. GRB990123, OSSE observations
  40. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  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. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  47. GRB990123 Optical Observations
  48. GRB 990123 Spectroscopic Redshifts
  49. GRB 990123: New Optical Observations, Decay Measure
  50. GRB 990123 Optical Follow-Up
  51. GRB 990123: Possible Gravitationally Lensed Burst?
  52. GRB 990123 optical observations
  53. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  54. GRB 990123 radio observations
  55. GRB 990123, new radio source
  56. GRB990123, Optical observation
  57. GRB 990123: Optical Decay Slope
  58. GRB 990123 r-band photometry
  59. GRB 990123 Optical Follow-up
  60. GRB990123, early optical counterpart detection
  61. GRB990123 Optical Observation
  62. GRB 990123: Bright New Source, Possible Optical Transient
  63. GRB 990123, Radio observations
  64. SN 1999E & GRB 980919
  65. Possible identification of SN1999E with GRB980910
  66. Optical Observations of GRB 981220
  67. GRB 981226: radio variable
  68. GRB981220
  69. GRB981220, Optical Observations
  70. GRB 981220 Optical observations
  71. GRB 981226 Optical Observations
  72. GRB 980613: Spectroscopy of the host galaxy
  73. GRB981226, sub-millimeter observations
  74. GRB981220, sub-millimeter observations
  75. GRB 981220 and GRB 981226, optical observations
  76. GRB 981226 radio observations
  77. GRB 981226
  78. GRB 981226 optical observations
  79. radio observations of GRB 981226
  80. GRB981220 B, R and I band observations
  81. GRB 981220:Optical Observations
  82. GRB 981220 optical R and I observations
  83. GRB981226, BeppoSAX Christmas GRB
  84. GRB 981226 - Infrared Observations
  85. GRB 981226 optical observations
  86. GRB 981220
  87. GRB 981220, radio observations
  88. GRB981226 Optical Observation
  89. GRB 981220, radio observations
  90. GRB 981220: BeppoSAX/GRBM results
  91. GRB981220 I-band Observations
  92. GRB 981220
  93. GRB 981220 Optical Observations
  94. GRB 981220, optical observations
  95. GRB 980326/Host Galaxy
  96. GRB981220 IPN error box
  97. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  98. GRB980329 R,I flux calibration and R,I,K upper limits
  99. GRB980425: X-ray revised positions
  100. GRB 980923 BATSE Observations

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